Re: [Emc-users] Homebuilt encoder

[Leonardo Marsaglia]

>
> hit me from your PM address and I'll send it back. Steal what you can
> use. I'm at gheskett AT shentel DOT net
>

Done :)

El sáb, 2 abr 2022 a las 19:28, gene heskett ()
escribió:

> On Saturday, 2 April 2022 17:14:35 EDT Leonardo Marsaglia wrote:
> > But it is one possble solution to Leonardo's problem. If Leonardo, you
> >
> > > want to look at my .hal, & borrow some of it, pm me your email
> > > address
> > > and I'll attatch it to a reply.
> >
> > Did you mean Andrew? :)
> >
>
> No, you.
>
> > Anyway, I was curious about your setup because I read several times
> > about the gearbox and how you managed to solve all the ratio issues in
> > HAL but I think I never saw the detailed explanation. Really nice on
> > how you managed to get the ratios accurately. If I just could have
> > more time at work (most of the time I'm involved in the manufacturing
> > of the camshafts) I surely could play a lot with HAL and it's infinite
> > possibilities.
>
> I agree, hal, if you can imagine it, can do it. Its a quite large amount
> of thhe magic in LinuxCNC.
>
> > By the way, I'm always curious but I always forget to ask. Could it be
> > that the HAL implementation was entirely done by John Kasunich?
>
> Can't answer that, but a read of the src should give a clue.
>
> hit me from your PM address and I'll send it back. Steal what you can
> use. I'm at gheskett AT shentel DOT net
>
> Cheers, Gene Heskett.
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
>
>
>
>
>
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>

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Re: [Emc-users] Homebuilt encoder

[gene heskett]

On Saturday, 2 April 2022 17:14:35 EDT Leonardo Marsaglia wrote:
> But it is one possble solution to Leonardo's problem. If Leonardo, you
> 
> > want to look at my .hal, & borrow some of it, pm me your email
> > address
> > and I'll attatch it to a reply.
> 
> Did you mean Andrew? :)
> 

No, you.

> Anyway, I was curious about your setup because I read several times
> about the gearbox and how you managed to solve all the ratio issues in
> HAL but I think I never saw the detailed explanation. Really nice on
> how you managed to get the ratios accurately. If I just could have
> more time at work (most of the time I'm involved in the manufacturing
> of the camshafts) I surely could play a lot with HAL and it's infinite
> possibilities.

I agree, hal, if you can imagine it, can do it. Its a quite large amount 
of thhe magic in LinuxCNC.
 
> By the way, I'm always curious but I always forget to ask. Could it be
> that the HAL implementation was entirely done by John Kasunich?

Can't answer that, but a read of the src should give a clue.

hit me from your PM address and I'll send it back. Steal what you can 
use. I'm at gheskett AT shentel DOT net

Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis





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Re: [Emc-users] Homebuilt encoder

[Leonardo Marsaglia]

But it is one possble solution to Leonardo's problem. If Leonardo, you
> want to look at my .hal, & borrow some of it, pm me your email address
> and I'll attatch it to a reply.


Did you mean Andrew? :)

Anyway, I was curious about your setup because I read several times about
the gearbox and how you managed to solve all the ratio issues in HAL but I
think I never saw the detailed explanation. Really nice on how you managed
to get the ratios accurately. If I just could have more time at work (most
of the time I'm involved in the manufacturing of the camshafts) I surely
could play a lot with HAL and it's infinite possibilities.

By the way, I'm always curious but I always forget to ask. Could it be that
the HAL implementation was entirely done by John Kasunich?

El sáb, 2 abr 2022 a las 13:30, gene heskett ()
escribió:

> On Saturday, 2 April 2022 10:04:58 EDT ken.stra...@gmail.com wrote:
> > Agreed about making an encoder and I have an Omron unit with A/B/Z
> > outputs "in the mail" from China.
> >
> > The drawbar for my R8 spindle extends out the top of the spindle. It is
> > a hollow shaft encoder with an 8mm through hole but that is
> > insufficient to accommodate a drawbar. I suppose that I could couple
> > it to the top of the drawbar with some sort of slip coupling but that
> > has potential issues with alignment and coupling backlash. Perhaps I'm
> > not looking at things the correctly but it seems that the simplest
> > approach is using a pulley and belt to offset things. Also, the
> > encoder is rated for a maximum of 1 rpm and that is my max spindle
> > speed; I could reduce with a 2:1 pulley + belt.
>
> reduction will muck with the index, so stick with 1/1 pulleys.
> R8 spindles with the draw bolt sticking out of the top, are a dangerous
> place to put an encoder. I tried to make en optical bolted to the top of
> the drwabar cap but the room available and the tooling to cut slots so
> small, I was not able to make a disk accurately enough to work well, and
> for some reason, the 2-56 screws holding it to the drawbar cap kept
> coming loose which allowed the disk to saw blade thru the optics.
>
> So I bought an omron, and made an extension shaft for the rear of the
> motor shaft, drilling into the center dimple of the shaft and tapping it,
> and drive the encoder from there, but its about 7x faster than the
> spindle. I also put a piece of cut off steel screw rtv'd to the side of
> the drawbar cap and rigged an ats-667 hall effect sensor to use its as
> the index as the gearing between the motorshaft and the spindle made the
> encoders index into a random position signal. I fixed the gear ratio by
> adding switches to the gearshift knob and a bit of math in the hal file
> switches with the gears, so a tkinter tach dial remains dead accurate.
>
> Not knowing the gear ratio, I added some more hal modules to follow the
> encoder for 100 turns of the spindle according to the index pulses, and
> I'm lazy so I automated that so it displays the encoders count difference
> after 100 turns. Divide by 100, and put that into the SCALE for the
> spindles ini settings. Did that for both gears. Obtained the ratio and
> switched that in and out with the knob tallys in the hal file.
>
> With the better encoder, and its reduced quantization noise, I was able
> to use about 20x as much Pgain and more of both Igain and Dgain. My only
> problem is the non-simetry of the ats-667, its polarity changes with the
> direction and stays there until the next time the screw is approaching
> which resets it, then the actual, on time pulse is the second edge it
> outputs, but the edge direction is up for one direction, and down for the
> other. So it changes about 15 degrees depending on the direction, and
> that, in my thinking is a cause of the sloppy threads I get when rigid
> tapping. And it isn't helped by my g0704's column being a tad off
> vertical, so there is a slight sideways motion as it descends, tending to
> push the tap sideways as it descends even if very accuratly trammed.
>
> That I can fix, I just have not gotten a round tuit, with an offset
> module, maybe 2 driven by a scaled way down Z position. I *have* acquired
> the circular square to verify the correction.
>
> Its what you get when you buy the cheapest chinese mill almost big enough
> to be usefull. Putting ball screws and motors on the Grizzly G0704, was
> $1100 when I bought it. But ball screws does NOT make a silk purse out of
> the infamous sows ear.
>
> But it is one possble solution to Leonardo's problem. If Leonardo, you
> want to look at my .hal, & borrow some of it, pm me your email address
> and I'll attatch it to a reply.
>
> Take care and stay well.
>
> Cheers, Gene Heskett.
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
>
>
>
>
>

Re: [Emc-users] Homebuilt encoder

[John Dammeyer]

When I changed over from a 2HP 220VAC motor to an AC Servo for the spindle 
motor I knew it was also time to look at spindle encoding.  Cost of the AC 
Servo was just under half of a 2-phase 2HP + VFD.

If I was running toothed belts it would be a no brainer to use the AC Servo 
drive encoder outputs (which can also be divided to create a slower pulse 
train).  But for the moment that wasn't possible.

I've probably posted some of these photos but here's the AC Servo mounted with 
a new dual step pulley (and no intermediate pulley).  
http://www.autoartisans.com/mill/SpindleMotorPulley-5.jpg 
Notice the 4 step pulley on the spindle.  There's no room for any sort of 
pulley to encoder on the spindle.  This pulley is driven by a tapered cone so 
it's also not an easy fix.

I didn't want to damage the original pulley so I made a new one that was 2 step 
instead of 4 with a thick mounting plate on the bottom for the encoder.
http://www.autoartisans.com/mill/NewPulleys-1.jpg

Here's the encoder disk mounted to the pulley with LCNC for the machining 
including using the 4mm cutter for a G-Code program that expected a 3mm cutter. 
 8-(
http://www.autoartisans.com/mill/ShavedEncoderDisk.jpg

My 3D printer to the rescue (plus lathe for creating custom bolts to hold the 
bracket).
http://www.autoartisans.com/mill/SensorTrialFit.jpg

And the final brackets and interface board before it's all packaged into a box 
and the wires neatly routed.  
http://www.autoartisans.com/mill/SensorTestSetup.jpg

The biggest mistake was that the two pulleys aren't exactly 1:1 where a toothed 
one would have been.  (We won't talk about casting the taper backwards so the 
pulley is really upside down from what I wanted).  

Anyway I've found that my HAL file stuff and pulley speed reporting is still a 
bit flakey in order to scale the spindle speed to the true speed of the spindle 
motor which is controlled with step/dir rather than 0-10V.  The V belts aren't 
perfectly smooth so they also contribute jitter.

Until I switch to toothed belts and pulleys I'm not going to worry about that.
John


> -Original Message-
> From: ken.stra...@gmail.com [mailto:ken.stra...@gmail.com]
> Sent: April-02-22 7:05 AM
> To: 'Enhanced Machine Controller (EMC)'
> Subject: Re: [Emc-users] Homebuilt encoder
> 
> Agreed about making an encoder and I have an Omron unit with A/B/Z outputs
> "in the mail" from China.
> 
> The drawbar for my R8 spindle extends out the top of the spindle. It is a
> hollow shaft encoder with an 8mm through hole but that is insufficient to
> accommodate a drawbar. I suppose that I could couple it to the top of the
> drawbar with some sort of slip coupling but that has potential issues with
> alignment and coupling backlash. Perhaps I'm not looking at things the
> correctly but it seems that the simplest approach is using a pulley and belt
> to offset things. Also, the encoder is rated for a maximum of 1 rpm and
> that is my max spindle speed; I could reduce with a 2:1 pulley + belt.
> 
> Other suggestions are welcomed!
> 
> -Original Message-
> From: Chris Albertson 
> Sent: April 1, 2022 11:37 PM
> To: Enhanced Machine Controller (EMC) 
> Subject: Re: [Emc-users] Homebuilt encoder
> 
> It is hard to beat GT2.  It is the current state of the art in belt-tooth
> profile. (except for the identical G3)
> 
> But if you are using a belt, then just buy a $30 Omron encoder.  No need to
> build one as it would be hard to make a better encoder.  I doubt you could
> make an encoder as small and accurate as the Omron using normal CNC
> equipment.
> 
> But if you could fit a pulley to the spindle, why can't you fit an encoder
> disk?
> 
> 
> 
> On Fri, Apr 1, 2022 at 7:28 PM  wrote:
> 
> > There has been some good info on how to build an encoder on this thread.
> > My concern is how to couple an encoder to my mill spindle. Due to the
> > mill design it doesn't seem feasible to attach the encoder directly to
> > the spindle so I will need to use a belt drive. The spindle runs at up
> > to 10500 rpm. GT2 belts are readily available and the SDP-SI website
> > says that they can be used at up to 7500 feet per minute. I believe
> > that a 2-inch pulley spinning at 1 rpm would move the belt at
> > about 5,200 fpm so somewhat below the maximum. Is there a better belt
> choice?
> >
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
> 
> 
> --
> 
> Chris Albertson
> Redondo Beach, California
> 
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge

Re: [Emc-users] Homebuilt encoder

[gene heskett]

On Saturday, 2 April 2022 10:04:58 EDT ken.stra...@gmail.com wrote:
> Agreed about making an encoder and I have an Omron unit with A/B/Z
> outputs "in the mail" from China.
> 
> The drawbar for my R8 spindle extends out the top of the spindle. It is
> a hollow shaft encoder with an 8mm through hole but that is
> insufficient to accommodate a drawbar. I suppose that I could couple
> it to the top of the drawbar with some sort of slip coupling but that
> has potential issues with alignment and coupling backlash. Perhaps I'm
> not looking at things the correctly but it seems that the simplest
> approach is using a pulley and belt to offset things. Also, the
> encoder is rated for a maximum of 1 rpm and that is my max spindle
> speed; I could reduce with a 2:1 pulley + belt.

reduction will muck with the index, so stick with 1/1 pulleys.
R8 spindles with the draw bolt sticking out of the top, are a dangerous 
place to put an encoder. I tried to make en optical bolted to the top of 
the drwabar cap but the room available and the tooling to cut slots so 
small, I was not able to make a disk accurately enough to work well, and 
for some reason, the 2-56 screws holding it to the drawbar cap kept 
coming loose which allowed the disk to saw blade thru the optics.

So I bought an omron, and made an extension shaft for the rear of the 
motor shaft, drilling into the center dimple of the shaft and tapping it, 
and drive the encoder from there, but its about 7x faster than the 
spindle. I also put a piece of cut off steel screw rtv'd to the side of 
the drawbar cap and rigged an ats-667 hall effect sensor to use its as 
the index as the gearing between the motorshaft and the spindle made the 
encoders index into a random position signal. I fixed the gear ratio by 
adding switches to the gearshift knob and a bit of math in the hal file 
switches with the gears, so a tkinter tach dial remains dead accurate.

Not knowing the gear ratio, I added some more hal modules to follow the 
encoder for 100 turns of the spindle according to the index pulses, and 
I'm lazy so I automated that so it displays the encoders count difference 
after 100 turns. Divide by 100, and put that into the SCALE for the 
spindles ini settings. Did that for both gears. Obtained the ratio and 
switched that in and out with the knob tallys in the hal file.

With the better encoder, and its reduced quantization noise, I was able 
to use about 20x as much Pgain and more of both Igain and Dgain. My only 
problem is the non-simetry of the ats-667, its polarity changes with the 
direction and stays there until the next time the screw is approaching 
which resets it, then the actual, on time pulse is the second edge it 
outputs, but the edge direction is up for one direction, and down for the 
other. So it changes about 15 degrees depending on the direction, and 
that, in my thinking is a cause of the sloppy threads I get when rigid 
tapping. And it isn't helped by my g0704's column being a tad off 
vertical, so there is a slight sideways motion as it descends, tending to 
push the tap sideways as it descends even if very accuratly trammed.

That I can fix, I just have not gotten a round tuit, with an offset 
module, maybe 2 driven by a scaled way down Z position. I *have* acquired 
the circular square to verify the correction.

Its what you get when you buy the cheapest chinese mill almost big enough 
to be usefull. Putting ball screws and motors on the Grizzly G0704, was 
$1100 when I bought it. But ball screws does NOT make a silk purse out of 
the infamous sows ear.

But it is one possble solution to Leonardo's problem. If Leonardo, you 
want to look at my .hal, & borrow some of it, pm me your email address 
and I'll attatch it to a reply.

Take care and stay well.

Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis





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Re: [Emc-users] Homebuilt encoder

[ken.strauss]

Agreed about making an encoder and I have an Omron unit with A/B/Z outputs
"in the mail" from China. 

The drawbar for my R8 spindle extends out the top of the spindle. It is a
hollow shaft encoder with an 8mm through hole but that is insufficient to
accommodate a drawbar. I suppose that I could couple it to the top of the
drawbar with some sort of slip coupling but that has potential issues with
alignment and coupling backlash. Perhaps I'm not looking at things the
correctly but it seems that the simplest approach is using a pulley and belt
to offset things. Also, the encoder is rated for a maximum of 1 rpm and
that is my max spindle speed; I could reduce with a 2:1 pulley + belt. 

Other suggestions are welcomed!

-Original Message-
From: Chris Albertson  
Sent: April 1, 2022 11:37 PM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Homebuilt encoder

It is hard to beat GT2.  It is the current state of the art in belt-tooth
profile. (except for the identical G3)

But if you are using a belt, then just buy a $30 Omron encoder.  No need to
build one as it would be hard to make a better encoder.  I doubt you could
make an encoder as small and accurate as the Omron using normal CNC
equipment.

But if you could fit a pulley to the spindle, why can't you fit an encoder
disk?



On Fri, Apr 1, 2022 at 7:28 PM  wrote:

> There has been some good info on how to build an encoder on this thread.
> My concern is how to couple an encoder to my mill spindle. Due to the 
> mill design it doesn't seem feasible to attach the encoder directly to 
> the spindle so I will need to use a belt drive. The spindle runs at up 
> to 10500 rpm. GT2 belts are readily available and the SDP-SI website 
> says that they can be used at up to 7500 feet per minute. I believe 
> that a 2-inch pulley spinning at 1 rpm would move the belt at 
> about 5,200 fpm so somewhat below the maximum. Is there a better belt
choice?
>
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>


-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] Homebuilt encoder

[Chris Albertson]

It is hard to beat GT2.  It is the current state of the art in belt-tooth
profile. (except for the identical G3)

But if you are using a belt, then just buy a $30 Omron encoder.  No need to
build one as it would be hard to make a better encoder.  I doubt you could
make an encoder as small and accurate as the Omron using normal CNC
equipment.

But if you could fit a pulley to the spindle, why can't you fit an encoder
disk?



On Fri, Apr 1, 2022 at 7:28 PM  wrote:

> There has been some good info on how to build an encoder on this thread.
> My concern is how to couple an encoder to my mill spindle. Due to the mill
> design it doesn't seem feasible to attach the encoder directly to the
> spindle so I will need to use a belt drive. The spindle runs at up to 10500
> rpm. GT2 belts are readily available and the SDP-SI website says that they
> can be used at up to 7500 feet per minute. I believe that a 2-inch pulley
> spinning at 1 rpm would move the belt at about 5,200 fpm so somewhat
> below the maximum. Is there a better belt choice?
>
>
>
> ___
> Emc-users mailing list
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> https://lists.sourceforge.net/lists/listinfo/emc-users
>


-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] Homebuilt encoder

[ken.strauss]

There has been some good info on how to build an encoder on this thread. My 
concern is how to couple an encoder to my mill spindle. Due to the mill design 
it doesn't seem feasible to attach the encoder directly to the spindle so I 
will need to use a belt drive. The spindle runs at up to 10500 rpm. GT2 belts 
are readily available and the SDP-SI website says that they can be used at up 
to 7500 feet per minute. I believe that a 2-inch pulley spinning at 1 rpm 
would move the belt at about 5,200 fpm so somewhat below the maximum. Is there 
a better belt choice?



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Re: [Emc-users] Homebuilt encoder

[John Dammeyer]

> From: andy pugh [mailto:bodge...@gmail.com]
> 
> On Fri, 1 Apr 2022 at 00:28, John Dammeyer  wrote:
> 
> > That's the way I'd do it.
> 
> Not sure what we are discussing here. That is the way that I did it. :-)

Sorry.  Didn't mean to offend.  It was a compliment as in:  I'd do it that way 
too.  Likely the best solution!

I don't think the approach works for hand turning the spindle and having the 
lead screw track though.  Full quadrature and a separate index is likely needed 
for that.

John
> 
> --
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> � George Fitch, Atlanta Constitution Newspaper, 1912
> 
> 
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Re: [Emc-users] Homebuilt encoder

[andy pugh]

On Fri, 1 Apr 2022 at 00:28, John Dammeyer  wrote:

> That's the way I'd do it.

Not sure what we are discussing here. That is the way that I did it. :-)

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Homebuilt encoder

[John Dammeyer]

> -Original Message-
> From: andy pugh [mailto:bodge...@gmail.com]
> Sent: March-31-22 4:17 PM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Homebuilt encoder
> 
> On Fri, 1 Apr 2022 at 00:08, John Dammeyer  wrote:
> 
> > Thank you.  I'll see if I can't write up a detailed explanation on how it 
> > works.  Perhaps with some flow diagrams etc.
> 
> it basically keeps a running time window of where you would expect to
> see the next pulse (based on where the last one was +/- 10%, and if
> there isn't one it pretends that there was  (to keep the velocity and
> counts tidy). Then when there is a pulse it checks if the gap was the
> right size, and resets index if it was.
> 

That's the way I'd do it.   I see it also uses a ping pong buffer to allow 
accumulations while the calculations are being done.  

Have a few other things to work on first...

> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> � George Fitch, Atlanta Constitution Newspaper, 1912
> 
> 
> ___
> Emc-users mailing list
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Re: [Emc-users] Homebuilt encoder

[andy pugh]

On Fri, 1 Apr 2022 at 00:08, John Dammeyer  wrote:

> Thank you.  I'll see if I can't write up a detailed explanation on how it 
> works.  Perhaps with some flow diagrams etc.

it basically keeps a running time window of where you would expect to
see the next pulse (based on where the last one was +/- 10%, and if
there isn't one it pretends that there was  (to keep the velocity and
counts tidy). Then when there is a pulse it checks if the gap was the
right size, and resets index if it was.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Homebuilt encoder

[John Dammeyer]

> From: andy pugh [mailto:bodge...@gmail.com]
> 
> On Thu, 31 Mar 2022 at 23:02, John Dammeyer  wrote:
> 
> > Any idea where the source code is for that encoder missing tooth tracking?  
> > Looks like it would be an interesting read.
> 
> 
> It's in here somewhere.
> https://github.com/LinuxCNC/linuxcnc/blob/master/src/hal/components/encoder.c#L493
> 
> Though looking at the diff might make it easier to see it all at once:
> https://github.com/LinuxCNC/linuxcnc/commit/c73b402ad5a26a5509f8ba16915bb200fbe5d109

Thank you.  I'll see if I can't write up a detailed explanation on how it 
works.  Perhaps with some flow diagrams etc.

John



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Re: [Emc-users] Homebuilt encoder

[andy pugh]

On Thu, 31 Mar 2022 at 23:02, John Dammeyer  wrote:

> Any idea where the source code is for that encoder missing tooth tracking?  
> Looks like it would be an interesting read.


It's in here somewhere.
https://github.com/LinuxCNC/linuxcnc/blob/master/src/hal/components/encoder.c#L493

Though looking at the diff might make it easier to see it all at once:
https://github.com/LinuxCNC/linuxcnc/commit/c73b402ad5a26a5509f8ba16915bb200fbe5d109

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Homebuilt encoder

[John Dammeyer]

> From: andy pugh [mailto:bodge...@gmail.com]
> 
> On Thu, 31 Mar 2022 at 18:14, Chris Albertson  
> wrote:
> 
> > A trick used in automotive sensors is to have one missing slot.  Then
> > software resets the counter when the expected pulse does not happen
> 
> LinuxCNC can use these target wheels and sensors. They are actually
> almost ideal for a lathe, having a nice big bore.
> https://youtu.be/t48TnJQtbCw
> 
Hi Andy,
Any idea where the source code is for that encoder missing tooth tracking?  
Looks like it would be an interesting read.
John



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Re: [Emc-users] Homebuilt encoder

[John Dammeyer]

Works fine from WIN-7/WIN-10/Samsung phone.

> -Original Message-
> From: Lawrence Glaister [mailto:ve...@shaw.ca]
> Sent: March-31-22 12:22 PM
> To: emc-users@lists.sourceforge.net
> Subject: Re: [Emc-users] Homebuilt encoder
> 
> very strange... working fine here. maybe try the http version...
> using firefox 98.0.2 (64-bit) here.
> 
> 
> http://ve7it.cowlug.org/spindle-encoder.html
> 
> I would like to track down the issue, so please let me know if you find
> its browser related or any other clues I will dive into the server
> logs and see if they give any clues. See if multiple refreshes work...
> maybe its related to server load???
> 
> cheers
> Lawrence
> 
> 
> On 2022-03-31 11:52, Martin Dobbins wrote:
> > Same here,
> >
> > Martin
> >
> > 
> > From: Mark Wendt
> >
> > Link no worky.  Returns an error "The Request Entity is too Large".
> >
> > Mark
> >
> 
> 
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Re: [Emc-users] Homebuilt encoder

[dave engvall]

Works fine here. If someone had not commented I'd wouldn't  of had a clue.

Dave

On 3/31/22 12:54 PM, Martin Dobbins wrote:

Perfect, thanks!

Martin


From: Lawrence Glaister

very strange... working fine here. maybe try the http version...
using firefox 98.0.2 (64-bit) here.


http://ve7it.cowlug.org/spindle-encoder.html

I would like to track down the issue, so please let me know if you find
its browser related or any other clues I will dive into the server
logs and see if they give any clues. See if multiple refreshes work...
maybe its related to server load???

cheers
Lawrence


On 2022-03-31 11:52, Martin Dobbins wrote:

Same here,

Martin


From: Mark Wendt

Link no worky.  Returns an error "The Request Entity is too Large".

Mark



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Re: [Emc-users] Homebuilt encoder

[Martin Dobbins]

Perfect, thanks!

Martin


From: Lawrence Glaister

very strange... working fine here. maybe try the http version...
using firefox 98.0.2 (64-bit) here.


http://ve7it.cowlug.org/spindle-encoder.html

I would like to track down the issue, so please let me know if you find
its browser related or any other clues I will dive into the server
logs and see if they give any clues. See if multiple refreshes work...
maybe its related to server load???

cheers
Lawrence


On 2022-03-31 11:52, Martin Dobbins wrote:
> Same here,
>
> Martin
>
> 
> From: Mark Wendt
>
> Link no worky.  Returns an error "The Request Entity is too Large".
>
> Mark
>


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Re: [Emc-users] Homebuilt encoder

[Mark Wendt]

That one works just dandy.

Thanks,
Mark

On Thu, Mar 31, 2022 at 3:25 PM Lawrence Glaister  wrote:

> very strange... working fine here. maybe try the http version...
> using firefox 98.0.2 (64-bit) here.
>
>
> http://ve7it.cowlug.org/spindle-encoder.html
>
> I would like to track down the issue, so please let me know if you find
> its browser related or any other clues I will dive into the server
> logs and see if they give any clues. See if multiple refreshes work...
> maybe its related to server load???
>
> cheers
> Lawrence
>
>
> On 2022-03-31 11:52, Martin Dobbins wrote:
> > Same here,
> >
> > Martin
> >
> > 
> > From: Mark Wendt
> >
> > Link no worky.  Returns an error "The Request Entity is too Large".
> >
> > Mark
> >
>
>
> ___
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> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] Homebuilt encoder

[andy pugh]

On Thu, 31 Mar 2022 at 18:14, Chris Albertson  wrote:

> A trick used in automotive sensors is to have one missing slot.  Then
> software resets the counter when the expected pulse does not happen

LinuxCNC can use these target wheels and sensors. They are actually
almost ideal for a lathe, having a nice big bore.
https://youtu.be/t48TnJQtbCw

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Homebuilt encoder

[Lawrence Glaister]

very strange... working fine here. maybe try the http version...
using firefox 98.0.2 (64-bit) here.


http://ve7it.cowlug.org/spindle-encoder.html

I would like to track down the issue, so please let me know if you find 
its browser related or any other clues I will dive into the server 
logs and see if they give any clues. See if multiple refreshes work... 
maybe its related to server load???


cheers
Lawrence


On 2022-03-31 11:52, Martin Dobbins wrote:

Same here,

Martin


From: Mark Wendt

Link no worky.  Returns an error "The Request Entity is too Large".

Mark




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Re: [Emc-users] Homebuilt encoder

[andrew beck]

Thanks guys

I will see how this goes.

And sounds like it should be easy as

Does anyone know how to wire sensors to mesa card encoder?  Are they pnp or
npn?


Or can I just wire them straight into encoder input?

Regards

Andrew

On Fri, 1 Apr 2022, 07:30 Lawrence Glaister,  wrote:

> Hi Andrew,
> It has been a few years since I added a spindle encoder to my lathe. I
> have a web page describing the gruesome details that might give you some
> ideas and some gcode to play with for cutting the disks. This encoder is
> still in operation with the data being fed into a parallel port on an
> older PIII 700Mhz Del box running ubuntu 10.4.
>
> https://ve7it.cowlug.org/spindle-encoder.html
>
> cheers
>
> Lawrence VE7IT
>
> On 2022-03-31 10:10, Chris Albertson wrote:
> > On Wed, Mar 30, 2022 at 11:18 PM andrew beck 
> > wrote:
> >
> >> Hey guys will this work OK?
> >>
> >> I think it's the same as the one from amazon
> >>
> >> https://www.trademe.co.nz/3531064367
> >>
> >>
> >> And I'm thinking I may need two discs.  One above the other so I can
> use a
> >> index sensor on the top layer.   Or maybe stick a proxy sensor on it.
> >>
> >> Looks like they have a 6mm gap between the slots in the sensor.   Do you
> >> think a 1mm wide gap gap would be ok maybe in a 2 mm thick sheet?
> >
> >
> >
> > The link does not work for me.
> >
> > Ideally the slots and the space between the slots is the same.   But this
> > only really matters if
> > 1) you intend to double the resolution by looking at leading and trailing
> > edges.
> > 2) and when the spindle reverses direction there is a small error if the
> > geometry is asymmetric.  Maybe the error is too small to break a tap, I
> > don't know.
> >
> > If the plate is thinck relative to the slot width all that means is the
> > alignment most be good, with the IR beam exactly 90 degrees to the disk.
> > The Omron senors, when you look inside use a very thin disk, like brass
> > shim stock. This minimizes any error caused by misalignment.   The very
> > high-end sensor use glass disks with vapor deposited aluminum to block
> the
> > light.
> >
> > Don't bother with two disks, because alignment can never be 100% perfect.
> >   Simply drill a hole for the index or make one slot deeper.
> >
> > A trick used in automotive sensors is to have one missing slot.  Then
> > software resets the counter when the expected pulse does not happen  This
> > saves the cost of the third sensor but that only matters if you build a
> > million cars.  IR sensors cost only about $1.
> >
> >>
> >>
> >>
> >> On Mon, 28 Mar 2022, 07:35 Chris Albertson, 
> >> wrote:
> >>
> >>> Forgot to include a link.  You can buy the bare sensor but also you can
> >> buy
> >>> them on PCBs with connectors attached and ready to go.
> >>> amazon.com/Measuring-Optocoupler-Interrupter
> >>> <
> >>>
> >>
> https://www.amazon.com/Measuring-Optocoupler-Interrupter-Detection-Arduino%EF%BC%885pcs%EF%BC%89/dp/B08977QFK5/ref=sr_1_17?keywords=c+optical+sensor=1648405019=8-17
> 
> >>>
> >>> Best to use a thin aluminum plate to make the interrupter disk.   Make
> >> the
> >>> slots 50% duty cycle,You need three sensors for quadrature with
> >> index.
> >>>   The above sensor should directly interface to Measa or a parallel
> port
> >> or
> >>> some microcontroler.
> >>>
> >>>
> >>> On Sun, Mar 27, 2022 at 10:02 AM Chris Albertson <
> >>> albertson.ch...@gmail.com>
> >>> wrote:
> >>>
>  THis goes to 10K RPM?   that is 167 revolutions per second.  400 slots
>  means 70 KHz signal.
> 
>  Can you design an inductive sensor that does 70KHz but is also
> >> sensitive
>  enough for near zero RPM?   Optical sensors can work up to 1MHz with
> no
>  problem as they don't have any inductanve.You can buy a "C" space
>  sensor for a few dollars
> 
>  In either case, optical of inductive, you want a 50% "slot" where
> there
> >>> is
>  as much metal left as cut away  Then the "edges" of the square wave
> are
> >>> the
>  same in either direction. The 50% duty cycle in effect doubles the
>  sensor resolution.
> 
>  Why?  Think about the signal when the direction changes. You have
> >> two
>  sensors in quadrature and lets say one is being blocked and one is
> not,
> >>> I
>  think you want the turnaround to take as long for each sensor.
> 
> 
>  On Sun, Mar 27, 2022 at 2:22 AM Andy Pugh  wrote:
> 
> >
> >
> >> On 27 Mar 2022, at 08:09, andrew beck 
> >>> wrote:
> >>
> >> And is bigger dia better for higher resolution?
> >
> > Probably not, as it will perhaps have more scope to oscillate at
> >> 10,000
> > rpm.
> >
> > Don’t neglect the purely mechanical design of this fast-spinning
> part.
> >
> > Have you considered optical sensors rather than inductive?
> >
> > What will be counting the pulses?
> >
> > LinuxCNC can lathe-thread with one sensor.
> > But rigid-tapping is 

Re: [Emc-users] Homebuilt encoder

[Martin Dobbins]

Same here,

Martin


From: Mark Wendt

Link no worky.  Returns an error "The Request Entity is too Large".

Mark

On Thu, Mar 31, 2022 at 2:30 PM Lawrence Glaister  wrote:

> Hi Andrew,
> It has been a few years since I added a spindle encoder to my lathe. I
> have a web page describing the gruesome details that might give you some
> ideas and some gcode to play with for cutting the disks. This encoder is
> still in operation with the data being fed into a parallel port on an
> older PIII 700Mhz Del box running ubuntu 10.4.
>
> https://ve7it.cowlug.org/spindle-encoder.html
>
> cheers
>
> Lawrence VE7IT
>
> On 2022-03-31 10:10, Chris Albertson wrote:
> > On Wed, Mar 30, 2022 at 11:18 PM andrew beck 
> > wrote:
> >
> >> Hey guys will this work OK?
> >>
> >> I think it's the same as the one from amazon
> >>
> >> https://www.trademe.co.nz/3531064367
> >>
> >>
> >> And I'm thinking I may need two discs.  One above the other so I can
> use a
> >> index sensor on the top layer.   Or maybe stick a proxy sensor on it.
> >>
> >> Looks like they have a 6mm gap between the slots in the sensor.   Do you
> >> think a 1mm wide gap gap would be ok maybe in a 2 mm thick sheet?
> >
> >
> >
> > The link does not work for me.
> >
> > Ideally the slots and the space between the slots is the same.   But this
> > only really matters if
> > 1) you intend to double the resolution by looking at leading and trailing
> > edges.
> > 2) and when the spindle reverses direction there is a small error if the
> > geometry is asymmetric.  Maybe the error is too small to break a tap, I
> > don't know.
> >
> > If the plate is thinck relative to the slot width all that means is the
> > alignment most be good, with the IR beam exactly 90 degrees to the disk.
> > The Omron senors, when you look inside use a very thin disk, like brass
> > shim stock. This minimizes any error caused by misalignment.   The very
> > high-end sensor use glass disks with vapor deposited aluminum to block
> the
> > light.
> >
> > Don't bother with two disks, because alignment can never be 100% perfect.
> >   Simply drill a hole for the index or make one slot deeper.
> >
> > A trick used in automotive sensors is to have one missing slot.  Then
> > software resets the counter when the expected pulse does not happen  This
> > saves the cost of the third sensor but that only matters if you build a
> > million cars.  IR sensors cost only about $1.
> >
> >>
> >>
> >>
> >> On Mon, 28 Mar 2022, 07:35 Chris Albertson, 
> >> wrote:
> >>
> >>> Forgot to include a link.  You can buy the bare sensor but also you can
> >> buy
> >>> them on PCBs with connectors attached and ready to go.
> >>> amazon.com/Measuring-Optocoupler-Interrupter
> >>> <
> >>>
> >>
> https://www.amazon.com/Measuring-Optocoupler-Interrupter-Detection-Arduino%EF%BC%885pcs%EF%BC%89/dp/B08977QFK5/ref=sr_1_17?keywords=c+optical+sensor=1648405019=8-17
> 
> >>>
> >>> Best to use a thin aluminum plate to make the interrupter disk.   Make
> >> the
> >>> slots 50% duty cycle,You need three sensors for quadrature with
> >> index.
> >>>   The above sensor should directly interface to Measa or a parallel
> port
> >> or
> >>> some microcontroler.
> >>>
> >>>
> >>> On Sun, Mar 27, 2022 at 10:02 AM Chris Albertson <
> >>> albertson.ch...@gmail.com>
> >>> wrote:
> >>>
>  THis goes to 10K RPM?   that is 167 revolutions per second.  400 slots
>  means 70 KHz signal.
> 
>  Can you design an inductive sensor that does 70KHz but is also
> >> sensitive
>  enough for near zero RPM?   Optical sensors can work up to 1MHz with
> no
>  problem as they don't have any inductanve.You can buy a "C" space
>  sensor for a few dollars
> 
>  In either case, optical of inductive, you want a 50% "slot" where
> there
> >>> is
>  as much metal left as cut away  Then the "edges" of the square wave
> are
> >>> the
>  same in either direction. The 50% duty cycle in effect doubles the
>  sensor resolution.
> 
>  Why?  Think about the signal when the direction changes. You have
> >> two
>  sensors in quadrature and lets say one is being blocked and one is
> not,
> >>> I
>  think you want the turnaround to take as long for each sensor.
> 
> 
>  On Sun, Mar 27, 2022 at 2:22 AM Andy Pugh  wrote:
> 
> >
> >
> >> On 27 Mar 2022, at 08:09, andrew beck 
> >>> wrote:
> >>
> >> And is bigger dia better for higher resolution?
> >
> > Probably not, as it will perhaps have more scope to oscillate at
> >> 10,000
> > rpm.
> >
> > Don’t neglect the purely mechanical design of this fast-spinning
> part.
> >
> > Have you considered optical sensors rather than inductive?
> >
> > What will be counting the pulses?
> >
> > LinuxCNC can lathe-thread with one sensor.
> > But rigid-tapping is different as it needs to accurately detect the
> > reversal point. So you need three 

Re: [Emc-users] Homebuilt encoder

[johnd]

Nicely done!Sent from my Samsung S10
 Original message From: Lawrence Glaister  Date: 
2022-03-31  11:30 a.m.  (GMT-08:00) To: emc-users@lists.sourceforge.net 
Subject: Re: [Emc-users] Homebuilt encoder Hi Andrew,It has been a few years 
since I added a spindle encoder to my lathe. I have a web page describing the 
gruesome details that might give you some ideas and some gcode to play with for 
cutting the disks. This encoder is still in operation with the data being fed 
into a parallel port on an older PIII 700Mhz Del box running ubuntu 
10.4.https://ve7it.cowlug.org/spindle-encoder.htmlcheersLawrence VE7ITOn 
2022-03-31 10:10, Chris Albertson wrote:> On Wed, Mar 30, 2022 at 11:18 PM 
andrew beck > wrote:> >> Hey guys will this work 
OK?>>>> I think it's the same as the one from amazon>>>> 
https://www.trademe.co.nz/3531064367>>>>>> And I'm thinking I may need two 
discs.  One above the other so I can use a>> index sensor on the top layer.   
Or maybe stick a proxy sensor on it.>>>> Looks like they have a 6mm gap between 
the slots in the sensor.   Do you>> think a 1mm wide gap gap would be ok maybe 
in a 2 mm thick sheet?> > > > The link does not work for me.> > Ideally the 
slots and the space between the slots is the same.   But this> only really 
matters if> 1) you intend to double the resolution by looking at leading and 
trailing> edges.> 2) and when the spindle reverses direction there is a small 
error if the> geometry is asymmetric.  Maybe the error is too small to break a 
tap, I> don't know.> > If the plate is thinck relative to the slot width all 
that means is the> alignment most be good, with the IR beam exactly 90 degrees 
to the disk.> The Omron senors, when you look inside use a very thin disk, like 
brass> shim stock. This minimizes any error caused by misalignment.   The very> 
high-end sensor use glass disks with vapor deposited aluminum to block the> 
light.> > Don't bother with two disks, because alignment can never be 100% 
perfect.>   Simply drill a hole for the index or make one slot deeper.> > A 
trick used in automotive sensors is to have one missing slot.  Then> software 
resets the counter when the expected pulse does not happen  This> saves the 
cost of the third sensor but that only matters if you build a> million cars.  
IR sensors cost only about $1.> >>>>>>>> On Mon, 28 Mar 2022, 07:35 Chris 
Albertson, >> wrote:>>>>> Forgot to include a link.  
You can buy the bare sensor but also you can>> buy>>> them on PCBs with 
connectors attached and ready to go.>>> 
amazon.com/Measuring-Optocoupler-Interrupter>>> <>>>>> 
https://www.amazon.com/Measuring-Optocoupler-Interrupter-Detection-Arduino%EF%BC%885pcs%EF%BC%89/dp/B08977QFK5/ref=sr_1_17?keywords=c+optical+sensor=1648405019=8-17>>>>>>>>>>
 Best to use a thin aluminum plate to make the interrupter disk.   Make>> 
the>>> slots 50% duty cycle,    You need three sensors for quadrature with>> 
index.>>>   The above sensor should directly interface to Measa or a parallel 
port>> or>>> some microcontroler.>>>>>>>>> On Sun, Mar 27, 2022 at 10:02 AM 
Chris Albertson <>>> albertson.ch...@gmail.com>>>> wrote:>>>>>>> THis goes to 
10K RPM?   that is 167 revolutions per second.  400 slots>>>> means 70 KHz 
signal.>>>>>>>> Can you design an inductive sensor that does 70KHz but is 
also>> sensitive>>>> enough for near zero RPM?   Optical sensors can work up to 
1MHz with no>>>> problem as they don't have any inductanve.    You can buy a 
"C" space>>>> sensor for a few dollars>>>>>>>> In either case, optical of 
inductive, you want a 50% "slot" where there>>> is>>>> as much metal left as 
cut away  Then the "edges" of the square wave are>>> the>>>> same in either 
direction. The 50% duty cycle in effect doubles the>>>> sensor 
resolution.>>>>>>>> Why?  Think about the signal when the direction changes.
 You have>> two>>>> sensors in quadrature and lets say one is being blocked and 
one is not,>>> I>>>> think you want the turnaround to take as long for each 
sensor.>>>>>>>>>>>> On Sun, Mar 27, 2022 at 2:22 AM Andy Pugh 
 wrote:>>>>>>>>>>>>>>>>>>>> On 27 Mar 2022, at 08:09, 
andrew beck >>> wrote:>>>>>>>>>>>> And is bigger dia 
better f

Re: [Emc-users] Homebuilt encoder

[Mark Wendt]

Link no worky.  Returns an error "The Request Entity is too Large".

Mark

On Thu, Mar 31, 2022 at 2:30 PM Lawrence Glaister  wrote:

> Hi Andrew,
> It has been a few years since I added a spindle encoder to my lathe. I
> have a web page describing the gruesome details that might give you some
> ideas and some gcode to play with for cutting the disks. This encoder is
> still in operation with the data being fed into a parallel port on an
> older PIII 700Mhz Del box running ubuntu 10.4.
>
> https://ve7it.cowlug.org/spindle-encoder.html
>
> cheers
>
> Lawrence VE7IT
>
> On 2022-03-31 10:10, Chris Albertson wrote:
> > On Wed, Mar 30, 2022 at 11:18 PM andrew beck 
> > wrote:
> >
> >> Hey guys will this work OK?
> >>
> >> I think it's the same as the one from amazon
> >>
> >> https://www.trademe.co.nz/3531064367
> >>
> >>
> >> And I'm thinking I may need two discs.  One above the other so I can
> use a
> >> index sensor on the top layer.   Or maybe stick a proxy sensor on it.
> >>
> >> Looks like they have a 6mm gap between the slots in the sensor.   Do you
> >> think a 1mm wide gap gap would be ok maybe in a 2 mm thick sheet?
> >
> >
> >
> > The link does not work for me.
> >
> > Ideally the slots and the space between the slots is the same.   But this
> > only really matters if
> > 1) you intend to double the resolution by looking at leading and trailing
> > edges.
> > 2) and when the spindle reverses direction there is a small error if the
> > geometry is asymmetric.  Maybe the error is too small to break a tap, I
> > don't know.
> >
> > If the plate is thinck relative to the slot width all that means is the
> > alignment most be good, with the IR beam exactly 90 degrees to the disk.
> > The Omron senors, when you look inside use a very thin disk, like brass
> > shim stock. This minimizes any error caused by misalignment.   The very
> > high-end sensor use glass disks with vapor deposited aluminum to block
> the
> > light.
> >
> > Don't bother with two disks, because alignment can never be 100% perfect.
> >   Simply drill a hole for the index or make one slot deeper.
> >
> > A trick used in automotive sensors is to have one missing slot.  Then
> > software resets the counter when the expected pulse does not happen  This
> > saves the cost of the third sensor but that only matters if you build a
> > million cars.  IR sensors cost only about $1.
> >
> >>
> >>
> >>
> >> On Mon, 28 Mar 2022, 07:35 Chris Albertson, 
> >> wrote:
> >>
> >>> Forgot to include a link.  You can buy the bare sensor but also you can
> >> buy
> >>> them on PCBs with connectors attached and ready to go.
> >>> amazon.com/Measuring-Optocoupler-Interrupter
> >>> <
> >>>
> >>
> https://www.amazon.com/Measuring-Optocoupler-Interrupter-Detection-Arduino%EF%BC%885pcs%EF%BC%89/dp/B08977QFK5/ref=sr_1_17?keywords=c+optical+sensor=1648405019=8-17
> 
> >>>
> >>> Best to use a thin aluminum plate to make the interrupter disk.   Make
> >> the
> >>> slots 50% duty cycle,You need three sensors for quadrature with
> >> index.
> >>>   The above sensor should directly interface to Measa or a parallel
> port
> >> or
> >>> some microcontroler.
> >>>
> >>>
> >>> On Sun, Mar 27, 2022 at 10:02 AM Chris Albertson <
> >>> albertson.ch...@gmail.com>
> >>> wrote:
> >>>
>  THis goes to 10K RPM?   that is 167 revolutions per second.  400 slots
>  means 70 KHz signal.
> 
>  Can you design an inductive sensor that does 70KHz but is also
> >> sensitive
>  enough for near zero RPM?   Optical sensors can work up to 1MHz with
> no
>  problem as they don't have any inductanve.You can buy a "C" space
>  sensor for a few dollars
> 
>  In either case, optical of inductive, you want a 50% "slot" where
> there
> >>> is
>  as much metal left as cut away  Then the "edges" of the square wave
> are
> >>> the
>  same in either direction. The 50% duty cycle in effect doubles the
>  sensor resolution.
> 
>  Why?  Think about the signal when the direction changes. You have
> >> two
>  sensors in quadrature and lets say one is being blocked and one is
> not,
> >>> I
>  think you want the turnaround to take as long for each sensor.
> 
> 
>  On Sun, Mar 27, 2022 at 2:22 AM Andy Pugh  wrote:
> 
> >
> >
> >> On 27 Mar 2022, at 08:09, andrew beck 
> >>> wrote:
> >>
> >> And is bigger dia better for higher resolution?
> >
> > Probably not, as it will perhaps have more scope to oscillate at
> >> 10,000
> > rpm.
> >
> > Don’t neglect the purely mechanical design of this fast-spinning
> part.
> >
> > Have you considered optical sensors rather than inductive?
> >
> > What will be counting the pulses?
> >
> > LinuxCNC can lathe-thread with one sensor.
> > But rigid-tapping is different as it needs to accurately detect the
> > reversal point. So you need three channels for index and full
> >>> quadrature.
> >
> > Work out 

Re: [Emc-users] Homebuilt encoder

[Lawrence Glaister]

Hi Andrew,
It has been a few years since I added a spindle encoder to my lathe. I 
have a web page describing the gruesome details that might give you some 
ideas and some gcode to play with for cutting the disks. This encoder is 
still in operation with the data being fed into a parallel port on an 
older PIII 700Mhz Del box running ubuntu 10.4.


https://ve7it.cowlug.org/spindle-encoder.html

cheers

Lawrence VE7IT

On 2022-03-31 10:10, Chris Albertson wrote:

On Wed, Mar 30, 2022 at 11:18 PM andrew beck 
wrote:


Hey guys will this work OK?

I think it's the same as the one from amazon

https://www.trademe.co.nz/3531064367


And I'm thinking I may need two discs.  One above the other so I can use a
index sensor on the top layer.   Or maybe stick a proxy sensor on it.

Looks like they have a 6mm gap between the slots in the sensor.   Do you
think a 1mm wide gap gap would be ok maybe in a 2 mm thick sheet?




The link does not work for me.

Ideally the slots and the space between the slots is the same.   But this
only really matters if
1) you intend to double the resolution by looking at leading and trailing
edges.
2) and when the spindle reverses direction there is a small error if the
geometry is asymmetric.  Maybe the error is too small to break a tap, I
don't know.

If the plate is thinck relative to the slot width all that means is the
alignment most be good, with the IR beam exactly 90 degrees to the disk.
The Omron senors, when you look inside use a very thin disk, like brass
shim stock. This minimizes any error caused by misalignment.   The very
high-end sensor use glass disks with vapor deposited aluminum to block the
light.

Don't bother with two disks, because alignment can never be 100% perfect.
  Simply drill a hole for the index or make one slot deeper.

A trick used in automotive sensors is to have one missing slot.  Then
software resets the counter when the expected pulse does not happen  This
saves the cost of the third sensor but that only matters if you build a
million cars.  IR sensors cost only about $1.





On Mon, 28 Mar 2022, 07:35 Chris Albertson, 
wrote:


Forgot to include a link.  You can buy the bare sensor but also you can

buy

them on PCBs with connectors attached and ready to go.
amazon.com/Measuring-Optocoupler-Interrupter
<


https://www.amazon.com/Measuring-Optocoupler-Interrupter-Detection-Arduino%EF%BC%885pcs%EF%BC%89/dp/B08977QFK5/ref=sr_1_17?keywords=c+optical+sensor=1648405019=8-17




Best to use a thin aluminum plate to make the interrupter disk.   Make

the

slots 50% duty cycle,You need three sensors for quadrature with

index.

  The above sensor should directly interface to Measa or a parallel port

or

some microcontroler.


On Sun, Mar 27, 2022 at 10:02 AM Chris Albertson <
albertson.ch...@gmail.com>
wrote:


THis goes to 10K RPM?   that is 167 revolutions per second.  400 slots
means 70 KHz signal.

Can you design an inductive sensor that does 70KHz but is also

sensitive

enough for near zero RPM?   Optical sensors can work up to 1MHz with no
problem as they don't have any inductanve.You can buy a "C" space
sensor for a few dollars

In either case, optical of inductive, you want a 50% "slot" where there

is

as much metal left as cut away  Then the "edges" of the square wave are

the

same in either direction. The 50% duty cycle in effect doubles the
sensor resolution.

Why?  Think about the signal when the direction changes. You have

two

sensors in quadrature and lets say one is being blocked and one is not,

I

think you want the turnaround to take as long for each sensor.


On Sun, Mar 27, 2022 at 2:22 AM Andy Pugh  wrote:





On 27 Mar 2022, at 08:09, andrew beck 

wrote:


And is bigger dia better for higher resolution?


Probably not, as it will perhaps have more scope to oscillate at

10,000

rpm.

Don’t neglect the purely mechanical design of this fast-spinning part.

Have you considered optical sensors rather than inductive?

What will be counting the pulses?

LinuxCNC can lathe-thread with one sensor.
But rigid-tapping is different as it needs to accurately detect the
reversal point. So you need three channels for index and full

quadrature.


Work out what error you can accept in the reversal point detection

(as a

fraction of thread pitch) and you can get a feel for how many slots

you

need.




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--

Chris Albertson
Redondo Beach, California




--

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] Homebuilt encoder

[Chris Albertson]

On Wed, Mar 30, 2022 at 11:18 PM andrew beck 
wrote:

> Hey guys will this work OK?
>
> I think it's the same as the one from amazon
>
> https://www.trademe.co.nz/3531064367
>
>
> And I'm thinking I may need two discs.  One above the other so I can use a
> index sensor on the top layer.   Or maybe stick a proxy sensor on it.
>
> Looks like they have a 6mm gap between the slots in the sensor.   Do you
> think a 1mm wide gap gap would be ok maybe in a 2 mm thick sheet?



The link does not work for me.

Ideally the slots and the space between the slots is the same.   But this
only really matters if
1) you intend to double the resolution by looking at leading and trailing
edges.
2) and when the spindle reverses direction there is a small error if the
geometry is asymmetric.  Maybe the error is too small to break a tap, I
don't know.

If the plate is thinck relative to the slot width all that means is the
alignment most be good, with the IR beam exactly 90 degrees to the disk.
The Omron senors, when you look inside use a very thin disk, like brass
shim stock. This minimizes any error caused by misalignment.   The very
high-end sensor use glass disks with vapor deposited aluminum to block the
light.

Don't bother with two disks, because alignment can never be 100% perfect.
 Simply drill a hole for the index or make one slot deeper.

A trick used in automotive sensors is to have one missing slot.  Then
software resets the counter when the expected pulse does not happen  This
saves the cost of the third sensor but that only matters if you build a
million cars.  IR sensors cost only about $1.

>
>
>
> On Mon, 28 Mar 2022, 07:35 Chris Albertson, 
> wrote:
>
> > Forgot to include a link.  You can buy the bare sensor but also you can
> buy
> > them on PCBs with connectors attached and ready to go.
> > amazon.com/Measuring-Optocoupler-Interrupter
> > <
> >
> https://www.amazon.com/Measuring-Optocoupler-Interrupter-Detection-Arduino%EF%BC%885pcs%EF%BC%89/dp/B08977QFK5/ref=sr_1_17?keywords=c+optical+sensor=1648405019=8-17
> > >
> >
> > Best to use a thin aluminum plate to make the interrupter disk.   Make
> the
> > slots 50% duty cycle,You need three sensors for quadrature with
> index.
> >  The above sensor should directly interface to Measa or a parallel port
> or
> > some microcontroler.
> >
> >
> > On Sun, Mar 27, 2022 at 10:02 AM Chris Albertson <
> > albertson.ch...@gmail.com>
> > wrote:
> >
> > > THis goes to 10K RPM?   that is 167 revolutions per second.  400 slots
> > > means 70 KHz signal.
> > >
> > > Can you design an inductive sensor that does 70KHz but is also
> sensitive
> > > enough for near zero RPM?   Optical sensors can work up to 1MHz with no
> > > problem as they don't have any inductanve.You can buy a "C" space
> > > sensor for a few dollars
> > >
> > > In either case, optical of inductive, you want a 50% "slot" where there
> > is
> > > as much metal left as cut away  Then the "edges" of the square wave are
> > the
> > > same in either direction. The 50% duty cycle in effect doubles the
> > > sensor resolution.
> > >
> > > Why?  Think about the signal when the direction changes. You have
> two
> > > sensors in quadrature and lets say one is being blocked and one is not,
> > I
> > > think you want the turnaround to take as long for each sensor.
> > >
> > >
> > > On Sun, Mar 27, 2022 at 2:22 AM Andy Pugh  wrote:
> > >
> > >>
> > >>
> > >> > On 27 Mar 2022, at 08:09, andrew beck 
> > wrote:
> > >> >
> > >> > And is bigger dia better for higher resolution?
> > >>
> > >> Probably not, as it will perhaps have more scope to oscillate at
> 10,000
> > >> rpm.
> > >>
> > >> Don’t neglect the purely mechanical design of this fast-spinning part.
> > >>
> > >> Have you considered optical sensors rather than inductive?
> > >>
> > >> What will be counting the pulses?
> > >>
> > >> LinuxCNC can lathe-thread with one sensor.
> > >> But rigid-tapping is different as it needs to accurately detect the
> > >> reversal point. So you need three channels for index and full
> > quadrature.
> > >>
> > >> Work out what error you can accept in the reversal point detection
> (as a
> > >> fraction of thread pitch) and you can get a feel for how many slots
> you
> > >> need.
> > >>
> > >>
> > >>
> > >>
> > >> ___
> > >> Emc-users mailing list
> > >> Emc-users@lists.sourceforge.net
> > >> https://lists.sourceforge.net/lists/listinfo/emc-users
> > >>
> > >
> > >
> > > --
> > >
> > > Chris Albertson
> > > Redondo Beach, California
> > >
> >
> >
> > --
> >
> > Chris Albertson
> > Redondo Beach, California
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>


-- 

Chris Albertson

Re: [Emc-users] Homebuilt encoder

[John Dammeyer]

Mine only has 60 teeth and they aren't symmetrical but I didn't find any 
problems with rigid tapping.
John


> -Original Message-
> From: Sam Sokolik [mailto:samco...@gmail.com]
> Sent: March-31-22 6:54 AM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Homebuilt encoder
> 
> I don't know - maybe over-thinking this a bit?  I have 2 machines using
> gear tooth sensors.  Both rigid tap perfectly without issues.
> 
> http://electronicsam.com/images/matsuura/sensors1.jpg
> 
> On Thu, Mar 31, 2022 at 8:32 AM gene heskett  wrote:
> 
> > On Thursday, 31 March 2022 07:57:53 EDT andrew beck wrote:
> > > For those interested I decided I really should start to use the forum
> > > so people can search later for stuff hopefully I help someone.
> > >
> > > I have started on the gear sensor style encoder.
> > >
> > >
> > > Hope it works.  Let me know your thoughts
> > >
> > > https://forum.linuxcnc.org/show-your-stuff/45498-linuxcnc-machine-shop->
> > fun-thread
> > >
> > > Regards
> > >
> > > Andrew
> > >
> > > On Sun, 27 Mar 2022, 22:21 Andy Pugh,  wrote:
> > > > > On 27 Mar 2022, at 08:09, andrew beck 
> > > > > wrote:
> > > > >
> > > > > And is bigger dia better for higher resolution?
> > > >
> > > > Probably not, as it will perhaps have more scope to oscillate at
> > > > 10,000 rpm.
> > > >
> > > > Don�t neglect the purely mechanical design of this fast-spinning
> > > > part.
> > > >
> > > > Have you considered optical sensors rather than inductive?
> > > >
> > > > What will be counting the pulses?
> > > >
> > > > LinuxCNC can lathe-thread with one sensor.
> > > > But rigid-tapping is different as it needs to accurately detect the
> > > > reversal point. So you need three channels for index and full
> > > > quadrature.
> >
> > And this is the problem with useing an ats-667 gear sensor. It switches
> > on the approach, so the switch point, in only watching one edge, will
> > have a different switch point depending on the direction. Some day, I've
> > got the fix that.  Needs a circuit from the quad detectors direction
> > output, to dynamically switch the polarity of its pulse depending on
> > which direction the quad detector says its turning. Thats active
> > circuitry and needs to be MUCH faster than a hal thread. Probably in pure
> > hardware. Ideally for that, an edge detector watching and firing on both
> > edges with the first one "cocking" a trigger, and the second pulse then
> > gated to the index circuit. That way the pulse seen as an index would be
> > the one generated as the center of the trigger tooth is passing over the
> > center of the ats-667. The ats-667 stays in that state until the next
> > trigger is aproaching. So turning in one direction, its on 96% of the
> > time, but in the other direction its off 96% of the time.
> >
> > > > Work out what error you can accept in the reversal point detection
> > > > (as a fraction of thread pitch) and you can get a feel for how many
> > > > slots you need.
> > > >
> > > >
> > > >
> > > >
> > > > ___
> > > > Emc-users mailing list
> > > > Emc-users@lists.sourceforge.net
> > > > https://lists.sourceforge.net/lists/listinfo/emc-users
> > >
> > > ___
> > > Emc-users mailing list
> > > Emc-users@lists.sourceforge.net
> > > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
> >
> > Cheers, Gene Heskett.
> > --
> > "There are four boxes to be used in defense of liberty:
> >  soap, ballot, jury, and ammo. Please use in that order."
> > -Ed Howdershelt (Author, 1940)
> > If we desire respect for the law, we must first make the law respectable.
> >  - Louis D. Brandeis
> >
> >
> >
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
> 
> ___
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Re: [Emc-users] Homebuilt encoder

[Sam Sokolik]

I don't know - maybe over-thinking this a bit?  I have 2 machines using
gear tooth sensors.  Both rigid tap perfectly without issues.

http://electronicsam.com/images/matsuura/sensors1.jpg

On Thu, Mar 31, 2022 at 8:32 AM gene heskett  wrote:

> On Thursday, 31 March 2022 07:57:53 EDT andrew beck wrote:
> > For those interested I decided I really should start to use the forum
> > so people can search later for stuff hopefully I help someone.
> >
> > I have started on the gear sensor style encoder.
> >
> >
> > Hope it works.  Let me know your thoughts
> >
> > https://forum.linuxcnc.org/show-your-stuff/45498-linuxcnc-machine-shop->
> fun-thread
> >
> > Regards
> >
> > Andrew
> >
> > On Sun, 27 Mar 2022, 22:21 Andy Pugh,  wrote:
> > > > On 27 Mar 2022, at 08:09, andrew beck 
> > > > wrote:
> > > >
> > > > And is bigger dia better for higher resolution?
> > >
> > > Probably not, as it will perhaps have more scope to oscillate at
> > > 10,000 rpm.
> > >
> > > Don’t neglect the purely mechanical design of this fast-spinning
> > > part.
> > >
> > > Have you considered optical sensors rather than inductive?
> > >
> > > What will be counting the pulses?
> > >
> > > LinuxCNC can lathe-thread with one sensor.
> > > But rigid-tapping is different as it needs to accurately detect the
> > > reversal point. So you need three channels for index and full
> > > quadrature.
>
> And this is the problem with useing an ats-667 gear sensor. It switches
> on the approach, so the switch point, in only watching one edge, will
> have a different switch point depending on the direction. Some day, I've
> got the fix that.  Needs a circuit from the quad detectors direction
> output, to dynamically switch the polarity of its pulse depending on
> which direction the quad detector says its turning. Thats active
> circuitry and needs to be MUCH faster than a hal thread. Probably in pure
> hardware. Ideally for that, an edge detector watching and firing on both
> edges with the first one "cocking" a trigger, and the second pulse then
> gated to the index circuit. That way the pulse seen as an index would be
> the one generated as the center of the trigger tooth is passing over the
> center of the ats-667. The ats-667 stays in that state until the next
> trigger is aproaching. So turning in one direction, its on 96% of the
> time, but in the other direction its off 96% of the time.
>
> > > Work out what error you can accept in the reversal point detection
> > > (as a fraction of thread pitch) and you can get a feel for how many
> > > slots you need.
> > >
> > >
> > >
> > >
> > > ___
> > > Emc-users mailing list
> > > Emc-users@lists.sourceforge.net
> > > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
>
> Cheers, Gene Heskett.
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
>
>
>
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] Homebuilt encoder

[Martin Dobbins]

I hope those are NZ $ and not US $ 


From: andrew beck

Hey guys will this work OK?

I think it's the same as the one from amazon

https://www.trademe.co.nz/3531064367


And I'm thinking I may need two discs.  One above the other so I can use a
index sensor on the top layer.   Or maybe stick a proxy sensor on it.

Looks like they have a 6mm gap between the slots in the sensor.   Do you
think a 1mm wide gap gap would be ok maybe in a 2 mm thick sheet?



On Mon, 28 Mar 2022, 07:35 Chris Albertson, 
wrote:

> Forgot to include a link.  You can buy the bare sensor but also you can buy
> them on PCBs with connectors attached and ready to go.
> amazon.com/Measuring-Optocoupler-Interrupter
> <
> https://www.amazon.com/Measuring-Optocoupler-Interrupter-Detection-Arduino%EF%BC%885pcs%EF%BC%89/dp/B08977QFK5/ref=sr_1_17?keywords=c+optical+sensor=1648405019=8-17
> >
>
> Best to use a thin aluminum plate to make the interrupter disk.   Make the
> slots 50% duty cycle,You need three sensors for quadrature with index.
>  The above sensor should directly interface to Measa or a parallel port or
> some microcontroler.
>
>
> On Sun, Mar 27, 2022 at 10:02 AM Chris Albertson <
> albertson.ch...@gmail.com>
> wrote:
>
> > THis goes to 10K RPM?   that is 167 revolutions per second.  400 slots
> > means 70 KHz signal.
> >
> > Can you design an inductive sensor that does 70KHz but is also sensitive
> > enough for near zero RPM?   Optical sensors can work up to 1MHz with no
> > problem as they don't have any inductanve.You can buy a "C" space
> > sensor for a few dollars
> >
> > In either case, optical of inductive, you want a 50% "slot" where there
> is
> > as much metal left as cut away  Then the "edges" of the square wave are
> the
> > same in either direction. The 50% duty cycle in effect doubles the
> > sensor resolution.
> >
> > Why?  Think about the signal when the direction changes. You have two
> > sensors in quadrature and lets say one is being blocked and one is not,
> I
> > think you want the turnaround to take as long for each sensor.
> >
> >
> > On Sun, Mar 27, 2022 at 2:22 AM Andy Pugh  wrote:
> >
> >>
> >>
> >> > On 27 Mar 2022, at 08:09, andrew beck 
> wrote:
> >> >
> >> > And is bigger dia better for higher resolution?
> >>
> >> Probably not, as it will perhaps have more scope to oscillate at 10,000
> >> rpm.
> >>
> >> Don’t neglect the purely mechanical design of this fast-spinning part.
> >>
> >> Have you considered optical sensors rather than inductive?
> >>
> >> What will be counting the pulses?
> >>
> >> LinuxCNC can lathe-thread with one sensor.
> >> But rigid-tapping is different as it needs to accurately detect the
> >> reversal point. So you need three channels for index and full
> quadrature.
> >>
> >> Work out what error you can accept in the reversal point detection (as a
> >> fraction of thread pitch) and you can get a feel for how many slots you
> >> need.
> >>
> >>
> >>
> >>
> >> ___
> >> Emc-users mailing list
> >> Emc-users@lists.sourceforge.net
> >> https://lists.sourceforge.net/lists/listinfo/emc-users
> >>
> >
> >
> > --
> >
> > Chris Albertson
> > Redondo Beach, California
> >
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
>
> ___
> Emc-users mailing list
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> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] Homebuilt encoder

[Martin Dobbins]

Splendid idea, it's easier to search for stuff over there that it is here.

Thanks for doing that,

Martin


From: andrew beck

For those interested I decided I really should start to use the forum so
people can search later for stuff hopefully I help someone.

I have started on the gear sensor style encoder.


Hope it works.  Let me know your thoughts

https://forum.linuxcnc.org/show-your-stuff/45498-linuxcnc-machine-shop-fun-thread

Regards

Andrew

On Sun, 27 Mar 2022, 22:21 Andy Pugh,  wrote:

>
>
> > On 27 Mar 2022, at 08:09, andrew beck  wrote:
> >
> > And is bigger dia better for higher resolution?
>
> Probably not, as it will perhaps have more scope to oscillate at 10,000
> rpm.
>
> Don’t neglect the purely mechanical design of this fast-spinning part.
>
> Have you considered optical sensors rather than inductive?
>
> What will be counting the pulses?
>
> LinuxCNC can lathe-thread with one sensor.
> But rigid-tapping is different as it needs to accurately detect the
> reversal point. So you need three channels for index and full quadrature.
>
> Work out what error you can accept in the reversal point detection (as a
> fraction of thread pitch) and you can get a feel for how many slots you
> need.
>
>
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] Homebuilt encoder

[gene heskett]

On Thursday, 31 March 2022 07:57:53 EDT andrew beck wrote:
> For those interested I decided I really should start to use the forum
> so people can search later for stuff hopefully I help someone.
> 
> I have started on the gear sensor style encoder.
> 
> 
> Hope it works.  Let me know your thoughts
> 
> https://forum.linuxcnc.org/show-your-stuff/45498-linuxcnc-machine-shop-> 
> fun-thread
> 
> Regards
> 
> Andrew
> 
> On Sun, 27 Mar 2022, 22:21 Andy Pugh,  wrote:
> > > On 27 Mar 2022, at 08:09, andrew beck 
> > > wrote:
> > > 
> > > And is bigger dia better for higher resolution?
> > 
> > Probably not, as it will perhaps have more scope to oscillate at
> > 10,000 rpm.
> > 
> > Don’t neglect the purely mechanical design of this fast-spinning
> > part.
> > 
> > Have you considered optical sensors rather than inductive?
> > 
> > What will be counting the pulses?
> > 
> > LinuxCNC can lathe-thread with one sensor.
> > But rigid-tapping is different as it needs to accurately detect the
> > reversal point. So you need three channels for index and full
> > quadrature.

And this is the problem with useing an ats-667 gear sensor. It switches 
on the approach, so the switch point, in only watching one edge, will 
have a different switch point depending on the direction. Some day, I've 
got the fix that.  Needs a circuit from the quad detectors direction 
output, to dynamically switch the polarity of its pulse depending on 
which direction the quad detector says its turning. Thats active 
circuitry and needs to be MUCH faster than a hal thread. Probably in pure 
hardware. Ideally for that, an edge detector watching and firing on both 
edges with the first one "cocking" a trigger, and the second pulse then 
gated to the index circuit. That way the pulse seen as an index would be 
the one generated as the center of the trigger tooth is passing over the 
center of the ats-667. The ats-667 stays in that state until the next 
trigger is aproaching. So turning in one direction, its on 96% of the 
time, but in the other direction its off 96% of the time.

> > Work out what error you can accept in the reversal point detection
> > (as a fraction of thread pitch) and you can get a feel for how many
> > slots you need.
> > 
> > 
> > 
> > 
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Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis





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Re: [Emc-users] Homebuilt encoder

[gene heskett]

On Thursday, 31 March 2022 03:41:01 EDT andy pugh wrote:
> On Thu, 31 Mar 2022 at 07:18, andrew beck  
wrote:
> > And I'm thinking I may need two discs.  One above the other so I can
> > use a index sensor on the top layer.
> 
> Generally one slot is made deeper, and a third sensor (possibly with a
> deeper fork) is used that can see the deeper section.

If 3, and they can be bent slightly, use the outside ones for quadrature, 
and the center one to read the long slot. I used honeywells for a couple 
years on my mill that way. Getting the mill to carve me a good disk in 
the size I had room for was the critical part.
> --
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> — George Fitch, Atlanta Constitution Newspaper, 1912
> 
> 
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Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis





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Re: [Emc-users] Homebuilt encoder

[andrew beck]

For those interested I decided I really should start to use the forum so
people can search later for stuff hopefully I help someone.

I have started on the gear sensor style encoder.


Hope it works.  Let me know your thoughts

https://forum.linuxcnc.org/show-your-stuff/45498-linuxcnc-machine-shop-fun-thread

Regards

Andrew

On Sun, 27 Mar 2022, 22:21 Andy Pugh,  wrote:

>
>
> > On 27 Mar 2022, at 08:09, andrew beck  wrote:
> >
> > And is bigger dia better for higher resolution?
>
> Probably not, as it will perhaps have more scope to oscillate at 10,000
> rpm.
>
> Don’t neglect the purely mechanical design of this fast-spinning part.
>
> Have you considered optical sensors rather than inductive?
>
> What will be counting the pulses?
>
> LinuxCNC can lathe-thread with one sensor.
> But rigid-tapping is different as it needs to accurately detect the
> reversal point. So you need three channels for index and full quadrature.
>
> Work out what error you can accept in the reversal point detection (as a
> fraction of thread pitch) and you can get a feel for how many slots you
> need.
>
>
>
>
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Re: [Emc-users] Homebuilt encoder

[andy pugh]

On Thu, 31 Mar 2022 at 07:18, andrew beck  wrote:

> And I'm thinking I may need two discs.  One above the other so I can use a
> index sensor on the top layer.

Generally one slot is made deeper, and a third sensor (possibly with a
deeper fork) is used that can see the deeper section.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Homebuilt encoder

[andrew beck]

Hey guys will this work OK?

I think it's the same as the one from amazon

https://www.trademe.co.nz/3531064367


And I'm thinking I may need two discs.  One above the other so I can use a
index sensor on the top layer.   Or maybe stick a proxy sensor on it.

Looks like they have a 6mm gap between the slots in the sensor.   Do you
think a 1mm wide gap gap would be ok maybe in a 2 mm thick sheet?



On Mon, 28 Mar 2022, 07:35 Chris Albertson, 
wrote:

> Forgot to include a link.  You can buy the bare sensor but also you can buy
> them on PCBs with connectors attached and ready to go.
> amazon.com/Measuring-Optocoupler-Interrupter
> <
> https://www.amazon.com/Measuring-Optocoupler-Interrupter-Detection-Arduino%EF%BC%885pcs%EF%BC%89/dp/B08977QFK5/ref=sr_1_17?keywords=c+optical+sensor=1648405019=8-17
> >
>
> Best to use a thin aluminum plate to make the interrupter disk.   Make the
> slots 50% duty cycle,You need three sensors for quadrature with index.
>  The above sensor should directly interface to Measa or a parallel port or
> some microcontroler.
>
>
> On Sun, Mar 27, 2022 at 10:02 AM Chris Albertson <
> albertson.ch...@gmail.com>
> wrote:
>
> > THis goes to 10K RPM?   that is 167 revolutions per second.  400 slots
> > means 70 KHz signal.
> >
> > Can you design an inductive sensor that does 70KHz but is also sensitive
> > enough for near zero RPM?   Optical sensors can work up to 1MHz with no
> > problem as they don't have any inductanve.You can buy a "C" space
> > sensor for a few dollars
> >
> > In either case, optical of inductive, you want a 50% "slot" where there
> is
> > as much metal left as cut away  Then the "edges" of the square wave are
> the
> > same in either direction. The 50% duty cycle in effect doubles the
> > sensor resolution.
> >
> > Why?  Think about the signal when the direction changes. You have two
> > sensors in quadrature and lets say one is being blocked and one is not,
> I
> > think you want the turnaround to take as long for each sensor.
> >
> >
> > On Sun, Mar 27, 2022 at 2:22 AM Andy Pugh  wrote:
> >
> >>
> >>
> >> > On 27 Mar 2022, at 08:09, andrew beck 
> wrote:
> >> >
> >> > And is bigger dia better for higher resolution?
> >>
> >> Probably not, as it will perhaps have more scope to oscillate at 10,000
> >> rpm.
> >>
> >> Don’t neglect the purely mechanical design of this fast-spinning part.
> >>
> >> Have you considered optical sensors rather than inductive?
> >>
> >> What will be counting the pulses?
> >>
> >> LinuxCNC can lathe-thread with one sensor.
> >> But rigid-tapping is different as it needs to accurately detect the
> >> reversal point. So you need three channels for index and full
> quadrature.
> >>
> >> Work out what error you can accept in the reversal point detection (as a
> >> fraction of thread pitch) and you can get a feel for how many slots you
> >> need.
> >>
> >>
> >>
> >>
> >> ___
> >> Emc-users mailing list
> >> Emc-users@lists.sourceforge.net
> >> https://lists.sourceforge.net/lists/listinfo/emc-users
> >>
> >
> >
> > --
> >
> > Chris Albertson
> > Redondo Beach, California
> >
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
>
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Re: [Emc-users] Homebuilt encoder

[ken.strauss]

Thanks but too late now. We'll see if I'm lucky.

-Original Message-
From: andy pugh  
Sent: March 28, 2022 8:42 AM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Homebuilt encoder

On Mon, 28 Mar 2022 at 03:14,  wrote:
>
> The Omron E6D-C series are rated at 12,000 rpm The Omron E6H-C series 
> are rated at 10,000 rpm
>
> I ordered an E6H from eBay with delivery promised in a month.

You need to be a little careful with those, some have no index. The advertisers 
don't appear to know the difference.
You can generally read the label in the photos to work it out.

--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is designed for 
the especial use of mechanical geniuses, daredevils and lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Homebuilt encoder

[andy pugh]

On Mon, 28 Mar 2022 at 03:14,  wrote:
>
> The Omron E6D-C series are rated at 12,000 rpm
> The Omron E6H-C series are rated at 10,000 rpm
>
> I ordered an E6H from eBay with delivery promised in a month.

You need to be a little careful with those, some have no index. The
advertisers don't appear to know the difference.
You can generally read the label in the photos to work it out.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Homebuilt encoder

[gene heskett]

On Sunday, 27 March 2022 19:25:42 EDT ken.stra...@gmail.com wrote:
> According to https://www.ia.omron.com/product/item/2463/ max RPM for
> that model (E6B2-CWZ6C-2000P) is 6000.
 
This I believe is the one, but I regularly spin it almost 3x faster than 
that.  Not for hours on end of course but it does get up there.

Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis





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Re: [Emc-users] Homebuilt encoder

[ken.strauss]

The Omron E6D-C series are rated at 12,000 rpm
The Omron E6H-C series are rated at 10,000 rpm

I ordered an E6H from eBay with delivery promised in a month. 
The vendor claims new and 20 available. See
https://www.ebay.ca/itm/183308776725


-Original Message-
From: Martin Dobbins  
Sent: March 27, 2022 9:09 PM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Homebuilt encoder

Yes, that's correct, it's also the same for 1000 ppr:

https://www.ia.omron.com/product/item/2450/

Martin

From: ken.stra...@gmail.com

According to https://www.ia.omron.com/product/item/2463/ max RPM for that
model (E6B2-CWZ6C-2000P) is 6000.

-Original Message-
From: Martin Dobbins 
Sent: March 27, 2022 6:44 PM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Homebuilt encoder

gene heskett 


>I'd just search ebay for Omron encoder, and get the 20 dollar or so
>1000 ppr differential version. I expect it would work.

Like this, maybe?

https://www.ebay.com/p/2159915706?iid=333709462343

oops that's a 2000 ppr

Martin




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Re: [Emc-users] Homebuilt encoder

[Martin Dobbins]

Yes, that's correct, it's also the same for 1000 ppr:

https://www.ia.omron.com/product/item/2450/

Martin

From: ken.stra...@gmail.com

According to https://www.ia.omron.com/product/item/2463/ max RPM for that
model (E6B2-CWZ6C-2000P) is 6000.

-Original Message-
From: Martin Dobbins 
Sent: March 27, 2022 6:44 PM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Homebuilt encoder

gene heskett 


>I'd just search ebay for Omron encoder, and get the 20 dollar or so
>1000 ppr differential version. I expect it would work.

Like this, maybe?

https://www.ebay.com/p/2159915706?iid=333709462343

oops that's a 2000 ppr

Martin




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Re: [Emc-users] Homebuilt encoder

[ken.strauss]

According to https://www.ia.omron.com/product/item/2463/ max RPM for that
model (E6B2-CWZ6C-2000P) is 6000.

-Original Message-
From: Martin Dobbins  
Sent: March 27, 2022 6:44 PM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Homebuilt encoder

gene heskett 


>I'd just search ebay for Omron encoder, and get the 20 dollar or so 
>1000 ppr differential version. I expect it would work.

Like this, maybe?

https://www.ebay.com/p/2159915706?iid=333709462343

oops that's a 2000 ppr

Martin




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Re: [Emc-users] Homebuilt encoder

[Martin Dobbins]

gene heskett 


>I'd just search ebay for Omron encoder, and get the 20 dollar or so 1000
>ppr differential version. I expect it would work.

Like this, maybe?

https://www.ebay.com/p/2159915706?iid=333709462343

oops that's a 2000 ppr

Martin




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Re: [Emc-users] Homebuilt encoder

[Dmitry Yurtaev]

i've made one with a TLE5012 chip. works for me up to 32krpm. i'm using SPI
interface, but the chip also has ABZ output
https://youtu.be/SIhoIOcmU-c

/dmitry

On Sun, Mar 27, 2022 at 10:09 AM andrew beck 
wrote:

> Hey guys
> I have a spindle encoder I want to set up for my 1rpm spindle on one of
> my cnc Mills
>
> I can laser cut a encoder disc and get some gear sensors.
>
> Max dia of the disc due to size constraints is 150 mm dia
>
> Questions are mainly design ones.
>
> What width of slots do I need in encoder disc?
>
> And is bigger dia better for higher resolution?
>
> Also what resolution do I need for good reliable rigid tapping?   I could
> probably laser cut a disc 140mm dia with 400 slots 1mm wide each if that
> would let the sensors work OK.
>
> But I don't really know what the sensors can pick up.
>
> Anyway if you guys have already done this I would appreciate the advice.
>
> Cheers
>
> Andrew
>
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Re: [Emc-users] Homebuilt encoder

[Sam Sokolik]

I am running a 48ish tooth gear with gear tooth sensors - it counts up to
10k with mesa.

http://electronicsam.com/images/greenmachine/20190401_150213.jpg
http://electronicsam.com/images/greenmachine/20190403_175734.jpg

sam



On Sun, Mar 27, 2022 at 4:27 PM dave engvall  wrote:

> At high rpm a resolver may make more sense ... and more $$. Depends. ??
>
> Dave
>
> On 3/27/22 2:03 PM, ken.stra...@gmail.com wrote:
> > Gene, do you have a part number for your high RPM Omron encoder? Maybe I
> can
> > snag one...
> >
> > -Original Message-
> > From: gene heskett 
> > Sent: March 27, 2022 4:49 PM
> > To: Enhanced Machine Controller (EMC) 
> > Subject: Re: [Emc-users] Homebuilt encoder
> >
> > On Sunday, 27 March 2022 15:45:48 EDT ken.stra...@gmail.com wrote:
> >> If you want spindle positioning (for more accurate probing of
> >> alignment for tool changes for examples) you'll need the encoder to
> >> follow the position at all speeds. Are there high RPM capable absolute
> >> encoders at a reasonable price?
> > The one I have on the rear end of that 1hp motor, an Omron 1000 ppr,
> cost me
> > $21 on fleabay 6 years ago. Its a differential model I'm converting to
> ttl
> > in a pair of rs485 to ttl interfaces that cost about $2 each, driving a
> 5i25
> > card. NO optics in that path. Absolute it is not, but if the encoder
> tracks,
> > who cares.
> >
> > Cheers, Gene Heskett.
> > --
> > "There are four boxes to be used in defense of liberty:
> >   soap, ballot, jury, and ammo. Please use in that order."
> > -Ed Howdershelt (Author, 1940)
> > If we desire respect for the law, we must first make the law respectable.
> >   - Louis D. Brandeis
> >
> >
> >
> >
> >
> > ___
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> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
> >
> >
> > ___
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>
>
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Re: [Emc-users] Homebuilt encoder

[gene heskett]

On Sunday, 27 March 2022 17:03:14 EDT ken.stra...@gmail.com wrote:
> Gene, do you have a part number for your high RPM Omron encoder? Maybe
> I can snag one...

I don't know as I do, and a spare I bought a couple years ago when the 
coupling broke is now buried in 2 or 3 years of detrious in the garage. I 
fixed the broken coupler by replacing it with some heat shrink that had 
the glue lining. The only thing special is that it was a differential 
output model but it was the same price as the TTL version. In fact I 
didn't realize I had bought the differential version till it arrived and 
I read the propaganda sheet that came with it.

A couple of the rs485<->TTL converters, programmed as send only, for 
about $2 a copy fixed that right up. Squeezed them into one of Hammonds 
smallest boxes in the middle of the cable, works fine. No room left for 
critters in that box though.

I'd just search ebay for Omron encoder, and get the 20 dollar or so 1000 
ppr differential version. I expect it would work.

Thanks Ken, take care and stay well.

Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis





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Re: [Emc-users] Homebuilt encoder

[dave engvall]

At high rpm a resolver may make more sense ... and more $$. Depends. ??

Dave

On 3/27/22 2:03 PM, ken.stra...@gmail.com wrote:

Gene, do you have a part number for your high RPM Omron encoder? Maybe I can
snag one...

-Original Message-
From: gene heskett 
Sent: March 27, 2022 4:49 PM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Homebuilt encoder

On Sunday, 27 March 2022 15:45:48 EDT ken.stra...@gmail.com wrote:

If you want spindle positioning (for more accurate probing of
alignment for tool changes for examples) you'll need the encoder to
follow the position at all speeds. Are there high RPM capable absolute
encoders at a reasonable price?

The one I have on the rear end of that 1hp motor, an Omron 1000 ppr, cost me
$21 on fleabay 6 years ago. Its a differential model I'm converting to ttl
in a pair of rs485 to ttl interfaces that cost about $2 each, driving a 5i25
card. NO optics in that path. Absolute it is not, but if the encoder tracks,
who cares.

Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
  soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
  - Louis D. Brandeis





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Re: [Emc-users] Homebuilt encoder

[ken.strauss]

Gene, do you have a part number for your high RPM Omron encoder? Maybe I can
snag one...

-Original Message-
From: gene heskett  
Sent: March 27, 2022 4:49 PM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Homebuilt encoder

On Sunday, 27 March 2022 15:45:48 EDT ken.stra...@gmail.com wrote:
> If you want spindle positioning (for more accurate probing of 
> alignment for tool changes for examples) you'll need the encoder to 
> follow the position at all speeds. Are there high RPM capable absolute 
> encoders at a reasonable price?

The one I have on the rear end of that 1hp motor, an Omron 1000 ppr, cost me
$21 on fleabay 6 years ago. Its a differential model I'm converting to ttl
in a pair of rs485 to ttl interfaces that cost about $2 each, driving a 5i25
card. NO optics in that path. Absolute it is not, but if the encoder tracks,
who cares.

Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis





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Re: [Emc-users] Homebuilt encoder

[gene heskett]

On Sunday, 27 March 2022 15:45:48 EDT ken.stra...@gmail.com wrote:
> If you want spindle positioning (for more accurate probing of alignment
> for tool changes for examples) you'll need the encoder to follow the
> position at all speeds. Are there high RPM capable absolute encoders
> at a reasonable price?

The one I have on the rear end of that 1hp motor, an Omron 1000 ppr, cost 
me $21 on fleabay 6 years ago. Its a differential model I'm converting to 
ttl in a pair of rs485 to ttl interfaces that cost about $2 each, driving 
a 5i25 card. NO optics in that path. Absolute it is not, but if the 
encoder tracks, who cares.

Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis





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Re: [Emc-users] Homebuilt encoder

[gene heskett]

On Sunday, 27 March 2022 15:31:15 EDT andrew beck wrote:
> I currently have a 1000 PPR encoder on it. And that rigid taps great.
> 
> Ideally I would like something similar
> 
> How fast can those sensors read?
> 
> 1000ppr at 10k rpm would be great
> 
> But just thinking about it.  I only actually need to be able to read
> encoder up to say 2000 rpm

Mine works to 3 grand. But that's multiplied by 7 due the head gearing at 
the motor shaft where that encoder lives. So my 1 hp rated motor at 90 
volts, is turning a hair over 21k revs, with a 125 volt power supply when 
wide open. And it hasn't even needed brushes in 7 years of that.
> 
> At high speed it doesn't matter

In most cases the spindle goes wide open when the encoder or the input 
stuff on your interface dies cuz its not fast enough. I've had to bypass 
slow opto's on $20 breakout cards quite a few times.

> On Sun, 27 Mar 2022, 22:21 Andy Pugh,  wrote:
> > > On 27 Mar 2022, at 08:09, andrew beck 
> > > wrote:
> > > 
> > > And is bigger dia better for higher resolution?
> > 
> > Probably not, as it will perhaps have more scope to oscillate at
> > 10,000 rpm.
> > 
> > Don’t neglect the purely mechanical design of this fast-spinning
> > part.
> > 
> > Have you considered optical sensors rather than inductive?
> > 
> > What will be counting the pulses?
> > 
> > LinuxCNC can lathe-thread with one sensor.
> > But rigid-tapping is different as it needs to accurately detect the
> > reversal point. So you need three channels for index and full
> > quadrature.
> > 
> > Work out what error you can accept in the reversal point detection
> > (as a fraction of thread pitch) and you can get a feel for how many
> > slots you need.
> > 
> > 
> > 
> > 
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> 
> ___
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> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis





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Re: [Emc-users] Homebuilt encoder

[gene heskett]

On Sunday, 27 March 2022 15:40:35 EDT andrew beck wrote:
> Chris just reading your email again and looks like the sensors you
> linked are good up to 1 mhz so I'm good to go.
> 
> How wide a slot do you think they need to read the light through?
> 
> If they could read 0.5mm that would be great
> 
> But I probably don't need that accuracy.
> 
> I just want it as good as I can get as I know I'll be tapping several
> thousand holes.
> 
> 400 PPR x4 is 1600 PPR.
> 
> M12 tap pitch is 1.75mm
> 
> 1.75/1600=0.001mm
> 
> Which is plenty lol.
> 
> Maybe I'll try this.
> 
> Can I use halscope to check the sensors are making good quadrature
> 

Yes and no. The halscope quantizes the time according to which thread it 
is being clocked with, and that can, except at quite low speeds, lie like 
a rug. Since those come into linuxcnc from hardware, you'd be much closer 
to seeing the truth with an external scope. Even with a 10mhz scope. This 
is a case of all the scope bandwidth the budget will buy.
 
> 
> On Mon, 28 Mar 2022, 06:06 Chris Albertson, 
> wrote:
> > THis goes to 10K RPM?   that is 167 revolutions per second.  400
> > slots
> > means 70 KHz signal.
> > 
> > Can you design an inductive sensor that does 70KHz but is also
> > sensitive enough for near zero RPM?   Optical sensors can work up to
> > 1MHz with no problem as they don't have any inductanve.You can
> > buy a "C" space sensor for a few dollars
> > 
> > In either case, optical of inductive, you want a 50% "slot" where
> > there is as much metal left as cut away  Then the "edges" of the
> > square wave are the same in either direction. The 50% duty cycle
> > in effect doubles the sensor resolution.
> > 
> > Why?  Think about the signal when the direction changes. You have
> > two sensors in quadrature and lets say one is being blocked and one
> > is not,  I think you want the turnaround to take as long for each
> > sensor.> 
> > On Sun, Mar 27, 2022 at 2:22 AM Andy Pugh  wrote:
> > > > On 27 Mar 2022, at 08:09, andrew beck 
> > 
> > wrote:
> > > > And is bigger dia better for higher resolution?
> > > 
> > > Probably not, as it will perhaps have more scope to oscillate at
> > > 10,000 rpm.
> > > 
> > > Don’t neglect the purely mechanical design of this fast-spinning
> > > part.
> > > 
> > > Have you considered optical sensors rather than inductive?
> > > 
> > > What will be counting the pulses?
> > > 
> > > LinuxCNC can lathe-thread with one sensor.
> > > But rigid-tapping is different as it needs to accurately detect the
> > > reversal point. So you need three channels for index and full
> > > quadrature.
> > > 
> > > Work out what error you can accept in the reversal point detection
> > > (as a fraction of thread pitch) and you can get a feel for how
> > > many slots you need.
> > > 
> > > 
> > > 
> > > 
> > > ___
> > > Emc-users mailing list
> > > Emc-users@lists.sourceforge.net
> > > https://lists.sourceforge.net/lists/listinfo/emc-users
> > 
> > --
> > 
> > Chris Albertson
> > Redondo Beach, California
> > 
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> 
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis





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Re: [Emc-users] Homebuilt encoder

[gene heskett]

On Sunday, 27 March 2022 14:31:16 EDT Chris Albertson wrote:
> Forgot to include a link.  You can buy the bare sensor but also you can
> buy them on PCBs with connectors attached and ready to go.
> amazon.com/Measuring-Optocoupler-Interrupter
>  uino%EF%BC%885pcs%EF%BC%89/dp/B08977QFK5/ref=sr_1_17?keywords=c+optical
> +sensor=1648405019=8-17>
> 
I didn't see anything there that was both fast enough and small enough.

I have no clue hor fast, but tearing down a gimpy mouse with get you 2 
that are small enough. @ near identical mice would get you 4 and you'd 
likely have a spare. Most mice die from broken solder joints where the 
finger switch meets the pcb.  And those mice interrupters are micro sized 
in comparison. Makiing the optical disk isn't that hard, I've done it 
several times. Getting the slot widths correct is the major problem.

> Best to use a thin aluminum plate to make the interrupter disk.

I've used .032 brass sheet, as it can be chemically blackened to 
discourge false triggers from the edges of well finished, shiny holes. So 
can the alu for that matter but its a flat black, and glossy is actually 
blacker. Black however is relative, you'd be far better to make sure its 
a flatter than a plate of pee before engraving it, and use an engraving 
bit so the edge reflections are well away from the receiver cell.  Far 
more effective to reflect the light away than to paint or chemically 
blacken it. Purposely dimming the ir led would also help.

> Make
> the slots 50% duty cycle,You need three sensors for quadrature
> with index. The above sensor should directly interface to Measa or a
> parallel port or some microcontroler.
> 
> 
> On Sun, Mar 27, 2022 at 10:02 AM Chris Albertson
> 
> wrote:
> > THis goes to 10K RPM?   that is 167 revolutions per second.  400
> > slots
> > means 70 KHz signal.
> > 
> > Can you design an inductive sensor that does 70KHz but is also
> > sensitive enough for near zero RPM?   Optical sensors can work up to
> > 1MHz with no problem as they don't have any inductanve.You can
> > buy a "C" space sensor for a few dollars
> > 
> > In either case, optical of inductive, you want a 50% "slot" where
> > there is as much metal left as cut away  Then the "edges" of the
> > square wave are the same in either direction. The 50% duty cycle
> > in effect doubles the sensor resolution.
> > 
> > Why?  Think about the signal when the direction changes. You have
> > two sensors in quadrature and lets say one is being blocked and one
> > is not,  I think you want the turnaround to take as long for each
> > sensor.> 
> > On Sun, Mar 27, 2022 at 2:22 AM Andy Pugh  wrote:
> >> > On 27 Mar 2022, at 08:09, andrew beck 
> >> > wrote:
> >> > 
> >> > And is bigger dia better for higher resolution?
> >> 
> >> Probably not, as it will perhaps have more scope to oscillate at
> >> 10,000 rpm.
> >> 
> >> Don’t neglect the purely mechanical design of this fast-spinning
> >> part.
> >> 
> >> Have you considered optical sensors rather than inductive?
> >> 
> >> What will be counting the pulses?
> >> 
> >> LinuxCNC can lathe-thread with one sensor.
> >> But rigid-tapping is different as it needs to accurately detect the
> >> reversal point. So you need three channels for index and full
> >> quadrature.
> >> 
> >> Work out what error you can accept in the reversal point detection
> >> (as a fraction of thread pitch) and you can get a feel for how many
> >> slots you need.
> >> 
> >> 
> >> 
> >> 
> >> ___
> >> Emc-users mailing list
> >> Emc-users@lists.sourceforge.net
> >> https://lists.sourceforge.net/lists/listinfo/emc-users
> > 
> > --
> > 
> > Chris Albertson
> > Redondo Beach, California
> 
> --
> 
> Chris Albertson
> Redondo Beach, California
> 
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis





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Re: [Emc-users] Homebuilt encoder

[ken.strauss]

If you want spindle positioning (for more accurate probing of alignment for 
tool changes for examples) you'll need the encoder to follow the position at 
all speeds. Are there high RPM capable absolute encoders at a reasonable price?

-Original Message-
From: andrew beck  
Sent: March 27, 2022 3:31 PM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Homebuilt encoder

I currently have a 1000 PPR encoder on it. And that rigid taps great.

Ideally I would like something similar

How fast can those sensors read?

1000ppr at 10k rpm would be great

But just thinking about it.  I only actually need to be able to read encoder up 
to say 2000 rpm

At high speed it doesn't matter

On Sun, 27 Mar 2022, 22:21 Andy Pugh,  wrote:

>
>
> > On 27 Mar 2022, at 08:09, andrew beck  wrote:
> >
> > And is bigger dia better for higher resolution?
>
> Probably not, as it will perhaps have more scope to oscillate at 
> 10,000 rpm.
>
> Don’t neglect the purely mechanical design of this fast-spinning part.
>
> Have you considered optical sensors rather than inductive?
>
> What will be counting the pulses?
>
> LinuxCNC can lathe-thread with one sensor.
> But rigid-tapping is different as it needs to accurately detect the 
> reversal point. So you need three channels for index and full quadrature.
>
> Work out what error you can accept in the reversal point detection (as 
> a fraction of thread pitch) and you can get a feel for how many slots 
> you need.
>
>
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] Homebuilt encoder

[andrew beck]

I have done that cutter size mistake on a 4k block of material before lol.
Oops

On Mon, 28 Mar 2022, 08:40 gene heskett,  wrote:

> On Sunday, 27 March 2022 15:20:22 EDT John Dammeyer wrote:
> > Just don't do what I did which is design the plate for a 3mm cutter and
> > then start the LCNC G-code with a 4mm cutter. John
>
> John, thats a mistake I might do. ;o)
>
> [...]
>
> Cheers, Gene Heskett.
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
>
>
>
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] Homebuilt encoder

[andrew beck]

John haha yep I'll not do that.

I'm thinking I'll use a 1mm cutter anyway if the sensors are good enough
for that

On Mon, 28 Mar 2022, 08:23 John Dammeyer,  wrote:

> Just don't do what I did which is design the plate for a 3mm cutter and
> then start the LCNC G-code with a 4mm cutter.
> John
>
> > -Original Message-
> > From: Chris Albertson [mailto:albertson.ch...@gmail.com]
> > Sent: March-27-22 11:31 AM
> > To: Enhanced Machine Controller (EMC)
> > Subject: Re: [Emc-users] Homebuilt encoder
> >
> > Forgot to include a link.  You can buy the bare sensor but also you can
> buy
> > them on PCBs with connectors attached and ready to go.
> > amazon.com/Measuring-Optocoupler-Interrupter
> > <https://www.amazon.com/Measuring-Optocoupler-Interrupter-Detection-
> >
> Arduino%EF%BC%885pcs%EF%BC%89/dp/B08977QFK5/ref=sr_1_17?keywords=c+optical+sensor=1648405019=8-17>
> >
> > Best to use a thin aluminum plate to make the interrupter disk.   Make
> the
> > slots 50% duty cycle,You need three sensors for quadrature with
> index.
> >  The above sensor should directly interface to Measa or a parallel port
> or
> > some microcontroler.
> >
> >
> > On Sun, Mar 27, 2022 at 10:02 AM Chris Albertson <
> albertson.ch...@gmail.com>
> > wrote:
> >
> > > THis goes to 10K RPM?   that is 167 revolutions per second.  400 slots
> > > means 70 KHz signal.
> > >
> > > Can you design an inductive sensor that does 70KHz but is also
> sensitive
> > > enough for near zero RPM?   Optical sensors can work up to 1MHz with no
> > > problem as they don't have any inductanve.You can buy a "C" space
> > > sensor for a few dollars
> > >
> > > In either case, optical of inductive, you want a 50% "slot" where
> there is
> > > as much metal left as cut away  Then the "edges" of the square wave
> are the
> > > same in either direction. The 50% duty cycle in effect doubles the
> > > sensor resolution.
> > >
> > > Why?  Think about the signal when the direction changes. You have
> two
> > > sensors in quadrature and lets say one is being blocked and one is
> not,  I
> > > think you want the turnaround to take as long for each sensor.
> > >
> > >
> > > On Sun, Mar 27, 2022 at 2:22 AM Andy Pugh  wrote:
> > >
> > >>
> > >>
> > >> > On 27 Mar 2022, at 08:09, andrew beck 
> wrote:
> > >> >
> > >> > And is bigger dia better for higher resolution?
> > >>
> > >> Probably not, as it will perhaps have more scope to oscillate at
> 10,000
> > >> rpm.
> > >>
> > >> Don�t neglect the purely mechanical design of this fast-spinning part.
> > >>
> > >> Have you considered optical sensors rather than inductive?
> > >>
> > >> What will be counting the pulses?
> > >>
> > >> LinuxCNC can lathe-thread with one sensor.
> > >> But rigid-tapping is different as it needs to accurately detect the
> > >> reversal point. So you need three channels for index and full
> quadrature.
> > >>
> > >> Work out what error you can accept in the reversal point detection
> (as a
> > >> fraction of thread pitch) and you can get a feel for how many slots
> you
> > >> need.
> > >>
> > >>
> > >>
> > >>
> > >> ___
> > >> Emc-users mailing list
> > >> Emc-users@lists.sourceforge.net
> > >> https://lists.sourceforge.net/lists/listinfo/emc-users
> > >>
> > >
> > >
> > > --
> > >
> > > Chris Albertson
> > > Redondo Beach, California
> > >
> >
> >
> > --
> >
> > Chris Albertson
> > Redondo Beach, California
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] Homebuilt encoder

[andrew beck]

Chris just reading your email again and looks like the sensors you linked
are good up to 1 mhz so I'm good to go.

How wide a slot do you think they need to read the light through?

If they could read 0.5mm that would be great

But I probably don't need that accuracy.

I just want it as good as I can get as I know I'll be tapping several
thousand holes.

400 PPR x4 is 1600 PPR.

M12 tap pitch is 1.75mm

1.75/1600=0.001mm

Which is plenty lol.

Maybe I'll try this.

Can I use halscope to check the sensors are making good quadrature




On Mon, 28 Mar 2022, 06:06 Chris Albertson, 
wrote:

> THis goes to 10K RPM?   that is 167 revolutions per second.  400 slots
> means 70 KHz signal.
>
> Can you design an inductive sensor that does 70KHz but is also sensitive
> enough for near zero RPM?   Optical sensors can work up to 1MHz with no
> problem as they don't have any inductanve.You can buy a "C" space
> sensor for a few dollars
>
> In either case, optical of inductive, you want a 50% "slot" where there is
> as much metal left as cut away  Then the "edges" of the square wave are the
> same in either direction. The 50% duty cycle in effect doubles the
> sensor resolution.
>
> Why?  Think about the signal when the direction changes. You have two
> sensors in quadrature and lets say one is being blocked and one is not,  I
> think you want the turnaround to take as long for each sensor.
>
>
> On Sun, Mar 27, 2022 at 2:22 AM Andy Pugh  wrote:
>
> >
> >
> > > On 27 Mar 2022, at 08:09, andrew beck 
> wrote:
> > >
> > > And is bigger dia better for higher resolution?
> >
> > Probably not, as it will perhaps have more scope to oscillate at 10,000
> > rpm.
> >
> > Don’t neglect the purely mechanical design of this fast-spinning part.
> >
> > Have you considered optical sensors rather than inductive?
> >
> > What will be counting the pulses?
> >
> > LinuxCNC can lathe-thread with one sensor.
> > But rigid-tapping is different as it needs to accurately detect the
> > reversal point. So you need three channels for index and full quadrature.
> >
> > Work out what error you can accept in the reversal point detection (as a
> > fraction of thread pitch) and you can get a feel for how many slots you
> > need.
> >
> >
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] Homebuilt encoder

[gene heskett]

On Sunday, 27 March 2022 15:20:22 EDT John Dammeyer wrote:
> Just don't do what I did which is design the plate for a 3mm cutter and
> then start the LCNC G-code with a 4mm cutter. John

John, thats a mistake I might do. ;o)

[...]

Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis





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Re: [Emc-users] Homebuilt encoder

[andrew beck]

I currently have a 1000 PPR encoder on it. And that rigid taps great.

Ideally I would like something similar

How fast can those sensors read?

1000ppr at 10k rpm would be great

But just thinking about it.  I only actually need to be able to read
encoder up to say 2000 rpm

At high speed it doesn't matter

On Sun, 27 Mar 2022, 22:21 Andy Pugh,  wrote:

>
>
> > On 27 Mar 2022, at 08:09, andrew beck  wrote:
> >
> > And is bigger dia better for higher resolution?
>
> Probably not, as it will perhaps have more scope to oscillate at 10,000
> rpm.
>
> Don’t neglect the purely mechanical design of this fast-spinning part.
>
> Have you considered optical sensors rather than inductive?
>
> What will be counting the pulses?
>
> LinuxCNC can lathe-thread with one sensor.
> But rigid-tapping is different as it needs to accurately detect the
> reversal point. So you need three channels for index and full quadrature.
>
> Work out what error you can accept in the reversal point detection (as a
> fraction of thread pitch) and you can get a feel for how many slots you
> need.
>
>
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] Homebuilt encoder

[Chris Albertson]

Forgot to include a link.  You can buy the bare sensor but also you can buy
them on PCBs with connectors attached and ready to go.
amazon.com/Measuring-Optocoupler-Interrupter


Best to use a thin aluminum plate to make the interrupter disk.   Make the
slots 50% duty cycle,You need three sensors for quadrature with index.
 The above sensor should directly interface to Measa or a parallel port or
some microcontroler.


On Sun, Mar 27, 2022 at 10:02 AM Chris Albertson 
wrote:

> THis goes to 10K RPM?   that is 167 revolutions per second.  400 slots
> means 70 KHz signal.
>
> Can you design an inductive sensor that does 70KHz but is also sensitive
> enough for near zero RPM?   Optical sensors can work up to 1MHz with no
> problem as they don't have any inductanve.You can buy a "C" space
> sensor for a few dollars
>
> In either case, optical of inductive, you want a 50% "slot" where there is
> as much metal left as cut away  Then the "edges" of the square wave are the
> same in either direction. The 50% duty cycle in effect doubles the
> sensor resolution.
>
> Why?  Think about the signal when the direction changes. You have two
> sensors in quadrature and lets say one is being blocked and one is not,  I
> think you want the turnaround to take as long for each sensor.
>
>
> On Sun, Mar 27, 2022 at 2:22 AM Andy Pugh  wrote:
>
>>
>>
>> > On 27 Mar 2022, at 08:09, andrew beck  wrote:
>> >
>> > And is bigger dia better for higher resolution?
>>
>> Probably not, as it will perhaps have more scope to oscillate at 10,000
>> rpm.
>>
>> Don’t neglect the purely mechanical design of this fast-spinning part.
>>
>> Have you considered optical sensors rather than inductive?
>>
>> What will be counting the pulses?
>>
>> LinuxCNC can lathe-thread with one sensor.
>> But rigid-tapping is different as it needs to accurately detect the
>> reversal point. So you need three channels for index and full quadrature.
>>
>> Work out what error you can accept in the reversal point detection (as a
>> fraction of thread pitch) and you can get a feel for how many slots you
>> need.
>>
>>
>>
>>
>> ___
>> Emc-users mailing list
>> Emc-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users
>>
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
>


-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] Homebuilt encoder

[Chris Albertson]

THis goes to 10K RPM?   that is 167 revolutions per second.  400 slots
means 70 KHz signal.

Can you design an inductive sensor that does 70KHz but is also sensitive
enough for near zero RPM?   Optical sensors can work up to 1MHz with no
problem as they don't have any inductanve.You can buy a "C" space
sensor for a few dollars

In either case, optical of inductive, you want a 50% "slot" where there is
as much metal left as cut away  Then the "edges" of the square wave are the
same in either direction. The 50% duty cycle in effect doubles the
sensor resolution.

Why?  Think about the signal when the direction changes. You have two
sensors in quadrature and lets say one is being blocked and one is not,  I
think you want the turnaround to take as long for each sensor.


On Sun, Mar 27, 2022 at 2:22 AM Andy Pugh  wrote:

>
>
> > On 27 Mar 2022, at 08:09, andrew beck  wrote:
> >
> > And is bigger dia better for higher resolution?
>
> Probably not, as it will perhaps have more scope to oscillate at 10,000
> rpm.
>
> Don’t neglect the purely mechanical design of this fast-spinning part.
>
> Have you considered optical sensors rather than inductive?
>
> What will be counting the pulses?
>
> LinuxCNC can lathe-thread with one sensor.
> But rigid-tapping is different as it needs to accurately detect the
> reversal point. So you need three channels for index and full quadrature.
>
> Work out what error you can accept in the reversal point detection (as a
> fraction of thread pitch) and you can get a feel for how many slots you
> need.
>
>
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>


-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] Homebuilt encoder

[Andy Pugh]

> On 27 Mar 2022, at 08:09, andrew beck  wrote:
> 
> And is bigger dia better for higher resolution?

Probably not, as it will perhaps have more scope to oscillate at 10,000 rpm. 

Don’t neglect the purely mechanical design of this fast-spinning part. 

Have you considered optical sensors rather than inductive?

What will be counting the pulses?

LinuxCNC can lathe-thread with one sensor. 
But rigid-tapping is different as it needs to accurately detect the reversal 
point. So you need three channels for index and full quadrature. 

Work out what error you can accept in the reversal point detection (as a 
fraction of thread pitch) and you can get a feel for how many slots you need. 




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