[Emc-users] Is there a more elegant way to drive the servo driver enable with mesa 7i76e

[linden]

An other question for the Electronics experts on here;

Is there a simple elegant way to drive the digital input 15 of the servo 
drive high to enable the servo using a digital output from the mesa 
7i76e. I have attached a drawing using a relay and the examples from the 
dmm manual. Any ideas or suggestions would be greatly appreciated. I am 
afraid i know just enough to be dangerous and am a little leery of 
blowing out the io pins.


thanks linden


Axis 0 ENA.pdf
Description: Adobe PDF document
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Re: [Emc-users] Making taper lock hubs

[Erik Christiansen]

On 26.03.17 18:53, Gene Heskett wrote:
> But is 7 the correct factor? It should be fairly easy to jack it back
> out.

Gene, I've never made one of them, but looking here:

http://www.google.com.au/url?sa=t=j==s=web=8=0ahUKEwiE6q-q5PXSAhWGKWMKHeZIAf0QFgg-MAc=http%3A%2F%2Funiversalbearings.com.au%2Fdownload-subproducts%2Ftaperlock-bushes=AFQjCNGOFIvAUjPQ1JccxaHkdEjC0hT5oA

the first bush in the table seems to be:

atan((35.2 - 33.7)/11.1) = 7.7° included, near as dammit.

They have a threaded half-hole on the perimeter, for a jacking screw,
so I figure that 8-ish degrees will not fall out as soon as you loosen
the screws.

So long as both parts are made with the same topslide angle setting, I
wouldn't fuss about 7° or 9°, or something round about close to that.
If the shaft isn't too shiny, and your bush bore isn't too polished,
then there's probably no need to go for the smallest angle (for tightest
grip), and another degree or two (included) will be a bit easier to
dismantle.

I can see why you're making them. There's not much in them, and with
prices being mostly loony if the goods don't come from China, it's well
worthwhile.

Erik

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Re: [Emc-users] Making taper lock hubs

[Gene Heskett]

On Sunday 26 March 2017 17:15:13 Marcus Bowman wrote:

> On 26 Mar 2017, at 21:15, Ken Strauss wrote:
> > Yes but for small angles sin() and tan() are almost identical.
> > Sin(7)=0.1219 and tan(7)=0.1228
>
> Yes; that's true. Is it not the half-angle anyway; so Tan 3.5 deg ?
> Or did I misinterpret the taper?
>
> Marcus
>
I believe if the lathe is in radius mode yes, but its in diameter mode 
ATM. The keyphrase in the machinery handbook is "included angle". Which 
would be 3.5 degrees off the axis of rotation, and correct for radius 
mode. I think...

> >> -Original Message-
> >> From: Marcus Bowman [mailto:marcus.bow...@visible.eclipse.co.uk]
> >> Sent: Sunday, March 26, 2017 3:53 PM
> >> To: Enhanced Machine Controller (EMC)
> >> Subject: Re: [Emc-users] Making taper lock hubs
> >>
> >> Is the tangent of the angle not more useful? That uses the straight
> >> length instead of the hypotenuse (along the tapered face).
> >> Opposite over adjacent, rather than opposite over hypotenuse.
> >>
> >> Marcus
> >>
> >> On 26 Mar 2017, at 19:48, Gene Heskett wrote:
> >>> Greetings everybody;
> >>>
> >>> As I read the machinists hand book, tapers such as this mean the
> >>> "included" angle, not the angle of just one side of a cone.
> >>>
> >>> So, I've read, where I don't recall, that a taper lock hub is 7
> >>> degrees of taper. It doesn't self eject, but also does not need a
> >>> lot of jacking force to unlock it.  Or is that magic angle
> >>> different, not 7
> >
> > degrees?
> >
> >>> The sin(7)=0.121869343405147462, which I interpret as meaning if
> >>> the tool travels an inch, the diameter change is
> >>> 0.121869343405147462.
> >>>
> >>> But the tool is moving only .735" from one end of the taper to the
> >>> other, so the additive value for the big end of the taper is then
> >>> .735*0.121869343405147462=0.0895739674027833847.  Since that is
> >>> better than angstrom accuracy, round it down to 4 or 5 digits
> >>> right of the decimal makes sense since I'm not carving a new
> >>> Hubble mirror here.
> >>>
> >>> So, bore is .876" (I overshot 7/8" a red one) and I'd like the
> >>> taper hub wall to be about 1/16" thick at the small end=1.".
> >>> Then the diameter at the flange, .735" to the left of that 1"
> >>> point, would 1.08957".
> >>>
> >>> Correct?

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)
Genes Web page 

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Re: [Emc-users] Making taper lock hubs

[Gene Heskett]

On Sunday 26 March 2017 16:15:33 Ken Strauss wrote:

> Yes but for small angles sin() and tan() are almost identical.
> Sin(7)=0.1219 and tan(7)=0.1228
>
I knew it was close, Ken but thats enough to let it wobble a bit, so I'll 
use the tan(7).  But is 7 the correct factor? It should be fairly easy 
to jack it back out.

Thanks, Ken.

> > -Original Message-
> > From: Marcus Bowman [mailto:marcus.bow...@visible.eclipse.co.uk]
> > Sent: Sunday, March 26, 2017 3:53 PM
> > To: Enhanced Machine Controller (EMC)
> > Subject: Re: [Emc-users] Making taper lock hubs
> >
> > Is the tangent of the angle not more useful? That uses the straight
> > length instead of the hypotenuse (along the tapered face).
> > Opposite over adjacent, rather than opposite over hypotenuse.
> >
> > Marcus
> >
> > On 26 Mar 2017, at 19:48, Gene Heskett wrote:
> > > Greetings everybody;
> > >
> > > As I read the machinists hand book, tapers such as this mean the
> > > "included" angle, not the angle of just one side of a cone.
> > >
> > > So, I've read, where I don't recall, that a taper lock hub is 7
> > > degrees of taper. It doesn't self eject, but also does not need a
> > > lot of jacking force to unlock it.  Or is that magic angle
> > > different, not 7
>
> degrees?
>
> > > The sin(7)=0.121869343405147462, which I interpret as meaning if
> > > the tool travels an inch, the diameter change is
> > > 0.121869343405147462.
> > >
> > > But the tool is moving only .735" from one end of the taper to the
> > > other, so the additive value for the big end of the taper is then
> > > .735*0.121869343405147462=0.0895739674027833847.  Since that is
> > > better than angstrom accuracy, round it down to 4 or 5 digits
> > > right of the decimal makes sense since I'm not carving a new
> > > Hubble mirror here.
> > >
> > > So, bore is .876" (I overshot 7/8" a red one) and I'd like the
> > > taper hub wall to be about 1/16" thick at the small end=1.".
> > > Then the diameter at the flange, .735" to the left of that 1"
> > > point, would 1.08957".
> > >
> > > Correct?
> > >
> > > Thanks. I might get this taper thing understood yet.
> > >
> > > 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)
> > > Genes Web page 
> > >
> > > --
> > >  Check out the vibrant tech community on one of the
> > > world's most engaging tech sites, Slashdot.org!
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>
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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)
Genes Web page 

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Re: [Emc-users] Making taper lock hubs

[Gene Heskett]

On Sunday 26 March 2017 15:53:03 Marcus Bowman wrote:

> Is the tangent of the angle not more useful? That uses the straight
> length instead of the hypotenuse (along the tapered face). Opposite
> over adjacent, rather than opposite over hypotenuse.
>
> Marcus

You're right I believe Marcus, makes perfect sense. That would make the 
diameter change of 7 degrees in a .735" run=0.090246652" or in this case 
to add to that end of the value being decremented.  Got it, thanks 
Marcus.  Now I need to paint that on the wall so I can remember it at my 
years. :(

I'll just invert that to machine the pulley.

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)
Genes Web page 

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Re: [Emc-users] Making taper lock hubs

[Andy Pugh]

> On 26 Mar 2017, at 21:15, Ken Strauss  wrote:
> 
> es but for small angles sin() and tan() are almost identical. Sin(7)=0.1219
> and tan(7)=0.1228

I recently discovered that I have been cutting BR30 specials wrong. 
Taper of all that type is 7/24. 
I have been using half of atan(7/24) when I should have been using the atan of 
half of 7/24. Makes about .14mm difference on a 30 size taper. 
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Re: [Emc-users] Making taper lock hubs

[Marcus Bowman]

On 26 Mar 2017, at 21:15, Ken Strauss wrote:

> Yes but for small angles sin() and tan() are almost identical. Sin(7)=0.1219
> and tan(7)=0.1228

Yes; that's true. Is it not the half-angle anyway; so Tan 3.5 deg ?
Or did I misinterpret the taper?

Marcus

> 
>> -Original Message-
>> From: Marcus Bowman [mailto:marcus.bow...@visible.eclipse.co.uk]
>> Sent: Sunday, March 26, 2017 3:53 PM
>> To: Enhanced Machine Controller (EMC)
>> Subject: Re: [Emc-users] Making taper lock hubs
>> 
>> Is the tangent of the angle not more useful? That uses the straight length
>> instead of the hypotenuse (along the tapered face).
>> Opposite over adjacent, rather than opposite over hypotenuse.
>> 
>> Marcus
>> 
>> 
>> On 26 Mar 2017, at 19:48, Gene Heskett wrote:
>> 
>>> Greetings everybody;
>>> 
>>> As I read the machinists hand book, tapers such as this mean the
>>> "included" angle, not the angle of just one side of a cone.
>>> 
>>> So, I've read, where I don't recall, that a taper lock hub is 7
>>> degrees of taper. It doesn't self eject, but also does not need a lot
>>> of jacking force to unlock it.  Or is that magic angle different, not 7
> degrees?
>>> 
>>> The sin(7)=0.121869343405147462, which I interpret as meaning if the
>>> tool travels an inch, the diameter change is 0.121869343405147462.
>>> 
>>> But the tool is moving only .735" from one end of the taper to the
>>> other, so the additive value for the big end of the taper is then
>>> .735*0.121869343405147462=0.0895739674027833847.  Since that is better
>>> than angstrom accuracy, round it down to 4 or 5 digits right of the
>>> decimal makes sense since I'm not carving a new Hubble mirror here.
>>> 
>>> So, bore is .876" (I overshot 7/8" a red one) and I'd like the taper
>>> hub wall to be about 1/16" thick at the small end=1.". Then the
>>> diameter at the flange, .735" to the left of that 1" point, would
>>> 1.08957".
>>> 
>>> Correct?
>>> 
>>> Thanks. I might get this taper thing understood yet.
>>> 
>>> 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)
>>> Genes Web page 
>>> 
>>> --
>>>  Check out the vibrant tech community on one of the world's
>>> most engaging tech sites, Slashdot.org! http://sdm.link/slashdot
>>> ___
>>> Emc-users mailing list
>>> Emc-users@lists.sourceforge.net
>>> https://lists.sourceforge.net/lists/listinfo/emc-users
>> 
>> 
>> 
> 
> --
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> 
> 
> 
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Re: [Emc-users] Making taper lock hubs

[Ken Strauss]

Yes but for small angles sin() and tan() are almost identical. Sin(7)=0.1219
and tan(7)=0.1228

> -Original Message-
> From: Marcus Bowman [mailto:marcus.bow...@visible.eclipse.co.uk]
> Sent: Sunday, March 26, 2017 3:53 PM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Making taper lock hubs
>
> Is the tangent of the angle not more useful? That uses the straight length
> instead of the hypotenuse (along the tapered face).
> Opposite over adjacent, rather than opposite over hypotenuse.
>
> Marcus
>
>
> On 26 Mar 2017, at 19:48, Gene Heskett wrote:
>
> > Greetings everybody;
> >
> > As I read the machinists hand book, tapers such as this mean the
> > "included" angle, not the angle of just one side of a cone.
> >
> > So, I've read, where I don't recall, that a taper lock hub is 7
> > degrees of taper. It doesn't self eject, but also does not need a lot
> > of jacking force to unlock it.  Or is that magic angle different, not 7
degrees?
> >
> > The sin(7)=0.121869343405147462, which I interpret as meaning if the
> > tool travels an inch, the diameter change is 0.121869343405147462.
> >
> > But the tool is moving only .735" from one end of the taper to the
> > other, so the additive value for the big end of the taper is then
> > .735*0.121869343405147462=0.0895739674027833847.  Since that is better
> > than angstrom accuracy, round it down to 4 or 5 digits right of the
> > decimal makes sense since I'm not carving a new Hubble mirror here.
> >
> > So, bore is .876" (I overshot 7/8" a red one) and I'd like the taper
> > hub wall to be about 1/16" thick at the small end=1.". Then the
> > diameter at the flange, .735" to the left of that 1" point, would
> > 1.08957".
> >
> > Correct?
> >
> > Thanks. I might get this taper thing understood yet.
> >
> > 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)
> > Genes Web page 
> >
> > --
> >  Check out the vibrant tech community on one of the world's
> > most engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
>
>

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Re: [Emc-users] Making taper lock hubs

[Marcus Bowman]

Is the tangent of the angle not more useful? That uses the straight length 
instead of the hypotenuse (along the tapered face).
Opposite over adjacent, rather than opposite over hypotenuse.

Marcus


On 26 Mar 2017, at 19:48, Gene Heskett wrote:

> Greetings everybody;
> 
> As I read the machinists hand book, tapers such as this mean 
> the "included" angle, not the angle of just one side of a cone.
> 
> So, I've read, where I don't recall, that a taper lock hub is 7 degrees 
> of taper. It doesn't self eject, but also does not need a lot of jacking 
> force to unlock it.  Or is that magic angle different, not 7 degrees?
> 
> The sin(7)=0.121869343405147462, which I interpret as meaning if the tool 
> travels an inch, the diameter change is 0.121869343405147462.
> 
> But the tool is moving only .735" from one end of the taper to the other, 
> so the additive value for the big end of the taper is 
> then .735*0.121869343405147462=0.0895739674027833847.  Since that is 
> better than angstrom accuracy, round it down to 4 or 5 digits right of 
> the decimal makes sense since I'm not carving a new Hubble mirror here.
> 
> So, bore is .876" (I overshot 7/8" a red one)
> and I'd like the taper hub wall to be about 1/16" thick at the small 
> end=1.". Then the diameter at the flange, .735" to the left of that 
> 1" point, would 1.08957".
> 
> Correct?
> 
> Thanks. I might get this taper thing understood yet.
> 
> 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)
> Genes Web page 
> 
> --
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
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> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


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Re: [Emc-users] More Renishaw questions

[Jon Elson]

On 03/26/2017 04:23 AM, Dave Caroline wrote:
> I have tried a SFH213 Photodiode with a comparator but it is a bit
> fiddly and not that sensitive, will try a QSE159 when it arrives.
>
>
I don't know exactly what they are doing, the data sheet is 
pretty sparse on details, but it seems they must have some 
feedback in the amplifier to keep it just below the trigger 
threshold without IR pulses.

It seemed to work well over quite a good range, although I 
suspect with the 12 LEDs that the Blum probe puts out a lot 
of IR.  I did work with a photodiode and oscilloscope, and 
could only see signals on the scope from a few inches away.  
So, the QSE159 ought to help out quite a bit.

Jon

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[Emc-users] Making taper lock hubs

[Gene Heskett]

Greetings everybody;

As I read the machinists hand book, tapers such as this mean 
the "included" angle, not the angle of just one side of a cone.

So, I've read, where I don't recall, that a taper lock hub is 7 degrees 
of taper. It doesn't self eject, but also does not need a lot of jacking 
force to unlock it.  Or is that magic angle different, not 7 degrees?

The sin(7)=0.121869343405147462, which I interpret as meaning if the tool 
travels an inch, the diameter change is 0.121869343405147462.

But the tool is moving only .735" from one end of the taper to the other, 
so the additive value for the big end of the taper is 
then .735*0.121869343405147462=0.0895739674027833847.  Since that is 
better than angstrom accuracy, round it down to 4 or 5 digits right of 
the decimal makes sense since I'm not carving a new Hubble mirror here.

So, bore is .876" (I overshot 7/8" a red one)
and I'd like the taper hub wall to be about 1/16" thick at the small 
end=1.". Then the diameter at the flange, .735" to the left of that 
1" point, would 1.08957".

Correct?

Thanks. I might get this taper thing understood yet.

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)
Genes Web page 

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Re: [Emc-users] advice on signal grounding between mesa 7i76e and dmm dyn4 servo drive

[Chris Albertson]

Never ground a shield at both ends.  If you do current can flow in the
shield.

Also every conductor that does cary current should have a conductors that
caries the opposite current  very close and running in parallel, preferably
the two are twisted together.   So, the power supply's return is paired
with the positive conductor.   Same for power leads going to motors and
ideally even signal lines are all paired (use differential signaling.)
 Ideally, these would all be inside their own shields and al the shields
would be ground at the same end at one place.

Yes, it is hard to follow these rules 100%   Some time positive and
negative terminals are separated by to much distance.  But try to do as
much as you can.

One fact to keep in mind, A twisted pair, where conductors cary opposing
current, even if the current is large produce in effect no electric field 8
wires diameters away.   The field self-cancels that quickly.  Twisting is
very effective.




On Sun, Mar 26, 2017 at 12:01 AM, linden  wrote:

> Hello All
>
> Should I ground both ends of the shield for shielded pair? I am not sure
> what the best practice is see pdf attached for what I have now in black and
> the chunk in red I am not sure about.
>
> --

Chris Albertson
Redondo Beach, California
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Re: [Emc-users] AC servo driver, Recommendations/advice requested

[Andrew]

2017-03-26 7:12 GMT+03:00 hubert:

>
> > You might ask Copley Controls if Xenus supports that encoder type.
> Thanks for bringing this up.
>I will report back here how this works out.  Reading the user guide
> for the REL and its software I found some references to Copley,  The
> data sheets look like replicas of the Xenus XTL and User guide for their
> HDM software looks like the Copley CME2 software.  The links from the
> Copeley Controls Data sheet on "HD SYSTEMS FHA Series Rotary Actuator
> with AC Brushless motor With Copley XTL Xenus Amplifier" to HD systems
> motor data files no longer worked, but I was able to locate them on the
> HDM site.  They included a file for my specific Actuator Model number so
> things are looking good.  So hopefully in a couple of weeks I will have
> the answers.  In the worst case I will be out some shipping fee's if I
> decide to return every thing.
>

Once I had a couple of similar actuators, iirc SHA 25, but could not find a
suitable drive back then, so I had to get rid of them. Now I have a Xenus
(which can drive almost any common motor, and Plus version supports even
more encoders) but don't have those actuators any more. So I'll be waiting
to see how it turns out.
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Re: [Emc-users] advice on signal grounding between mesa 7i76e and dmm dyn4 servo drive

[Gene Heskett]

On Sunday 26 March 2017 03:01:17 linden wrote:

> Hello All
>
> Should I ground both ends of the shield for shielded pair?

No, only one end. Actually I think best practice is a single #10 bolt in 
the middle of it all, to which all grounds and all cable shields are 
connected, with the grounds going here and there both heavy and 
insulated so they won't setup a ground loop by touching something on the 
way to connect a ground on something else.

This is called a star ground.

Shielded cables such as those from a stepper driver to its motor, I cut 
into the plastic sheath and separate the drain wire, and solder a 2" 
piece of 1/4" flat braid, with an eyelet crimped on one end, the other 
end folded over the drain wire and soldered to it, using a 2 or 3% 
silver bearing solder. Good connection, and stronger than the eutectic 
alloys. The eyelet gets dropped over the bolt and the nut replaced and 
tightened.

> I am not 
> sure what the best practice is see pdf attached for what I have now in
> black and the chunk in red I am not sure about.

I would not depend on the connector shell, trimming the shielding short 
so it doesn't touch there, nor at the motor, but does have the short tab 
described above soldered to the drain wire as it goes past the bolt on 
its way out of the box, and connected to the common ground bolt. You 
should run a piece of the braid from this bolt to the ground symbol 
terminal on the power supplies, then feed the drivers power from the 
psu's via twisted pair, and it may help if a ferrite clamp-on is applied 
close to the drivers motor outputs, and another applied at the psu 
outputs, so the bead covers both wires in each case. This will block 
the "longitudinal" noise but has no effect on the psu's switching noise. 
In my case the vfd's motor wires are in the same 1" conduit as the power 
coming in is in, and I had to put a 3 phase corcom 20 amp "brick wall" 
in the circuit as close to the vfd's output terminals as was practical, 
getting rid of the vfd's noise it was injecting into the incoming power 
for all my electronics. This has not appeared to have affected the vfd.

One other thing, there is not any filtering or shielding in the 5v runs 
to the encoders I installed to replace the hand cranks removed from this 
Sheldon 11x36 lathe, its all in cat 5 cable, and the returns from the 
encoder were loaded with high voltage electrical spikes on the corners 
of what should have been the 4.9 volt or so square waves it produces. So 
those signal wires now go past a board with 6 each (I buy them in 100 
packs) 1n914 diodes to ground for each signal wire so as to clamp the 
positive peaks to about 4 volts, and while its working, I may add 
another diode faceing the other way to clamp any ground undershoots to 
about -0.55 volts to protect the 7i90's inputs.

This board in particular seems to be more easily damaged by the noise 
spikes and static electricity*, than a 5i25, which I also am familiar 
with, but the 7i90 gives you I/O to throw away, ( 72 minus the 
generators and encoders enabled ) whereas the input facilities of the 
5i25 are limited to the 5 the parport offers, per connector, which it 
has 2 of.
 
*static electricity, generated  by my butt rubbing on the garage door 
behind the lathe as its been covered by an additional layer of 2" blue 
styrofoam from Lowes, adding another R11 to most of the door making my 
otherwise well insulated garage very easy to heat or air condition. So I 
have to slip on one of those wrist grounding straps when I'm working on 
the electronics to keep my charges down else I can blow the 7i90 with my 
generated static. I've BTDT too. :(

> The only other connections I have are:
>   - 24 volt supply for the mesa board going into TB3 pin22 as
> +24vdc - the corresponding ground from the power supply going into TB3
> pin 23

This - supply wire to T3-23  s/b grounded as it goes by that bolt.

>   - a jumper going from IO ground pin 9 on JP4 of the servo drive
> to TB3 pin 24

As should this wire UNLESS its internally connected to the TB3-23, verify 
with an ohm-meter.

Proper grounding can be tricky because you don't always know whats in the 
box. So keep a meter handy.

> Thanks for any help and advice
> linden

Thats my $0.02, but adjust for inflation since 1934. :) I am also a 
C.E.T. 

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)
Genes Web page 

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Re: [Emc-users] More Renishaw questions

[Dave Caroline]

I have tried a SFH213 Photodiode with a comparator but it is a bit
fiddly and not that sensitive, will try a QSE159 when it arrives.

Dave Caroline

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Re: [Emc-users] advice on signal grounding between mesa 7i76e and dmm dyn4 servo drive

[linden]

thanks Erik

I don't have any formal electronics back ground and have been 
struggling to get my head rapped around driving this servo with the mesa 
card. The documentation for both seems pretty good but it is all in a 
language I don't fully understand. It is very helpful having a second 
set of eyes going over my work and making sure things really work how i 
imagine they work in my head.

thanks again


linden


On 17-03-26 12:38 AM, Erik Christiansen wrote:
> On 26.03.17 00:01, linden wrote:
>> Hello All
>>
>> Should I ground both ends of the shield for shielded pair? I am not sure
>> what the best practice is see pdf attached for what I have now in black and
>> the chunk in red I am not sure about.
> Grounding the shield at both ends will create a ground loop, and
> therefore trouble. If the " JP4 Shell" in the drawing were only the
> connector shell, not connected to anything, then connecting to it would
> merely extend the screen right to the end. BUT you've added "Gnd" to the
> label, to indicate that it's grounded at that end, right? Draw a great
> looping line connecting the two "Gnd" labels. What do you have if the
> red connection is made?
>
> My preference is to ground screens at the driving end, and you've done
> that. No more is needed.
>
> Erik
>
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Re: [Emc-users] advice on signal grounding between mesa 7i76e and dmm dyn4 servo drive

[Erik Christiansen]

On 26.03.17 00:01, linden wrote:
> Hello All
> 
> Should I ground both ends of the shield for shielded pair? I am not sure
> what the best practice is see pdf attached for what I have now in black and
> the chunk in red I am not sure about.

Grounding the shield at both ends will create a ground loop, and
therefore trouble. If the " JP4 Shell" in the drawing were only the
connector shell, not connected to anything, then connecting to it would
merely extend the screen right to the end. BUT you've added "Gnd" to the
label, to indicate that it's grounded at that end, right? Draw a great
looping line connecting the two "Gnd" labels. What do you have if the
red connection is made?

My preference is to ground screens at the driving end, and you've done
that. No more is needed.

Erik

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[Emc-users] advice on signal grounding between mesa 7i76e and dmm dyn4 servo drive

[linden]

Hello All

Should I ground both ends of the shield for shielded pair? I am not sure 
what the best practice is see pdf attached for what I have now in black 
and the chunk in red I am not sure about.


The only other connections I have are:
 - 24 volt supply for the mesa board going into TB3 pin22 as +24vdc
 - the corresponding ground from the power supply going into TB3 
pin 23
 - a jumper going from IO ground pin 9 on JP4 of the servo drive to 
TB3 pin 24


Thanks for any help and advice
linden


Step and Direction Axis 0.pdf
Description: Adobe PDF document
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