On 4/20/22 13:26, Torsten Curdt via Emc-developers wrote:
But to me the whole idea breaks down when using a Closed Loop Stepper or
a
Servo.
At least unless you feed the encoders into LinuxCNC it seems to heavily
weaken the idea.
Yes, that's the whole idea! The encoder is read by
LinuxCNC,
The Fanuc drives on the mill used Fanus feedback but the drive had quad
output so I connected that to LinuxCNC
easy peasy simple
On Wed, Apr 20, 2022 at 5:59 PM Stuart Stevenson wrote:
> use the encoder feedback on both the motor drive and LinuxCNC
>
> On Wed, Apr 20, 2022 at 5:38 PM Sam
use the encoder feedback on both the motor drive and LinuxCNC
On Wed, Apr 20, 2022 at 5:38 PM Sam Sokolik wrote:
> Linuxcnc doesn't care where you close the feedback loop (linuxcnc always
> closes the feedback loop). Simple step/direction closes the loop between
> the step-gen and linuxcnc.
>
Linuxcnc doesn't care where you close the feedback loop (linuxcnc always
closes the feedback loop). Simple step/direction closes the loop between
the step-gen and linuxcnc.
sam
On Wed, Apr 20, 2022 at 3:57 PM Torsten Curdt via Emc-developers <
emc-developers@lists.sourceforge.net> wrote:
>
> > That said - that's a dual loop with two different encoders.
> > That's not really the same dual loop when you have LinuxCNC and a Closed
> > Loop Stepper/Servo Driver.
>
> If you only have one feedback source, how can you have a dual feedback
> loop? With the feedback closed on the driver,
Gentlemen,
Of the 5 machines I have put LinuxCNC on every one was closed loop servo
with LinuxCNC tuning the already tuned closed loop. The machines all ran
just fine. One of them was configured using the 'encoder' feedback
connected to the P and D and a linear scale connected to I. This machine
>
> That said - that's a dual loop with two different encoders.
> That's not really the same dual loop when you have LinuxCNC and a Closed
> Loop Stepper/Servo Driver.
If you only have one feedback source, how can you have a dual feedback
loop? With the feedback closed on the driver, your joint
> > Could you do e.g. rigid tapping when there is a LinuxCNC and another PID
> > loop on the motor driver?
>
> Granite devices has a good description of dual feedback loops (and a
> mention for linuxcnc). The inner velocity feedback loop is normally closed
> on the drive and the outer position
>
> Could you do e.g. rigid tapping when there is a LinuxCNC and another PID
> loop on the motor driver?
Granite devices has a good description of dual feedback loops (and a
mention for linuxcnc). The inner velocity feedback loop is normally closed
on the drive and the outer position loop by
On Wed, 20 Apr 2022 at 17:55, Torsten Curdt via Emc-developers
wrote:
>
> > If you wanted an alternative to Mesa there are always solutions from Jon or
> > you could use ethercat. Linuxcnc will not care at the tc level.
>
> I am falling short on finding those.
> Do you have a link?
On Wed, 20 Apr 2022 at 17:53, Torsten Curdt wrote:
> Does the HAL get the absolute Positions? And that gets translated into
> velocities?
It actually gets target feedback values, after homing. ie positions
scaled according to the encoder counts or step counts that applied
when it was homed.
> > But to me the whole idea breaks down when using a Closed Loop Stepper or
> a
> > Servo.
> > At least unless you feed the encoders into LinuxCNC it seems to heavily
> > weaken the idea.
>
> Yes, that's the whole idea! The encoder is read by
> LinuxCNC, PID processes the difference between
On 4/20/22 11:53, Torsten Curdt via Emc-developers wrote:
But to me the whole idea breaks down when using a Closed Loop Stepper or a
Servo.
At least unless you feed the encoders into LinuxCNC it seems to heavily
weaken the idea.
Yes, that's the whole idea! The encoder is read by
LinuxCNC,
> Also, the interpreter is a pluggable module, it doesn't have to be G-code.
>
That's a great design.
Every 1mS the tc calculates new positions for all axes, and puts those
> positions on to HAL pins.
>
Does the HAL get the absolute Positions? And that gets translated into
velocities?
I am
>
> Once implemented in
> hal (hardware extraction layer) via your hal file with loadrt and addf
> commands, your custom component has access to that infinite memory and CPU
> capability AND it is treated as if it is part of the Linuxcnc core viar the
> controlling servo thread.
>
That is indeed
On Mon, 18 Apr 2022, andy pugh wrote:
Date: Mon, 18 Apr 2022 00:59:07 +0100
From: andy pugh
Reply-To: EMC developers
To: EMC developers
Subject: Re: [Emc-developers] curious about the ethernet protocol
On Sat, 16 Apr 2022 at 00:42, Torsten Curdt via Emc-developers
wrote:
IIUC the GCODE
You can do all sorts of fancy stuff - with realtime tucked comfortably in
the computer... (not excluding torch height control all within linuxcnc)
https://www.youtube.com/shorts/nViXP9SsdWc
Linuxcnc is like a large real time lego set...
sam
On Sun, Apr 17, 2022 at 8:42 PM Rod Webster wrote:
So Andy's post brings is right back to Peters comment
Basically just following the LinuxCNC model of having the host be the
> locus of control. This is the basic difference between buffered systems
> like Mach and LinuxCNC. By having the LinuxCNC host be the controller
> you gain a number of
On Sat, 16 Apr 2022 at 00:42, Torsten Curdt via Emc-developers
wrote:
> IIUC the GCODE interpreter runs in the non-realtime part. It sends the step
> instructions to a card to execute the steps. This is obvious when using a
> LPT port, but how does this work via Ethernet?
There are some steps
> > Unfortunately that circles back to the mesa availability problems :-(
>
> 5i25's are not available? I haven't checked recently.
>
You can almost replace the Mesa store by an out-of-stock sign ;)
> Would a 7i92 also work?
>
> It looks like it would, its basicaly a 5i25 with a cat connector
>
On Sun, 17 Apr 2022, Torsten Curdt via Emc-developers wrote:
Date: Sun, 17 Apr 2022 13:47:40 +0200
From: Torsten Curdt via Emc-developers
To: EMC developers
Cc: Torsten Curdt
Subject: Re: [Emc-developers] curious about the ethernet protocol
Maybe finding an old parallel port machine might
On Sunday, 17 April 2022 11:00:31 EDT Jérémie Tarot wrote:
> Le dim. 17 avr. 2022 à 13:50, Torsten Curdt via Emc-developers <
>
> emc-developers@lists.sourceforge.net> a écrit :
> > > > Maybe finding an old parallel port machine might still be the
> > > > easier
> > > > route
> > > >
> > > > :-/
On Sunday, 17 April 2022 07:47:40 EDT Torsten Curdt via Emc-developers
wrote:
> > > Maybe finding an old parallel port machine might still be the
> > > easier
> > > route
> > >
> > > :-/
> >
> > Better yet, a pci-e buss and a 5i25 card.
>
> Unfortunately that circles back to the mesa
Le dim. 17 avr. 2022 à 13:50, Torsten Curdt via Emc-developers <
emc-developers@lists.sourceforge.net> a écrit :
> > > Maybe finding an old parallel port machine might still be the easier
> > > route
> > > :-/
> >
> > Better yet, a pci-e buss and a 5i25 card.
>
>
> Unfortunately that circles back
> > Maybe finding an old parallel port machine might still be the easier
> > route
> > :-/
>
> Better yet, a pci-e buss and a 5i25 card.
Unfortunately that circles back to the mesa availability problems :-(
Would a 7i92 also work?
Seems I either need to go with Remora or a Parallel BOB.
And I
On Sunday, 17 April 2022 05:57:07 EDT Torsten Curdt via Emc-developers
wrote:
> > BUT my ballscrews are 05mm and planned for servo speeds.
> >
> > > I don't really want to go from the idea of the dynamic servo driven
> > > machine to the stepper turtle :)
> >
> > All my stuff is steppers, but I
> BUT my ballscrews are 05mm and planned for servo speeds.
> >
> > I don't really want to go from the idea of the dynamic servo driven
> > machine to the stepper turtle :)
>
> All my stuff is steppers, but I wouldn't call a g0 move at 250 ipm a
> turtle. The whole steel framed table its on shakes.
>
> > It sounds like the ideal LinuxCNC setup would be a very dump driver
> > (without encoder support) and a stepper/servo with just an exposed
> encoder.
> > And then have LinuxCNC take care of everything.
> >
> But, then, you would be running blind, with no actual
> position available at the
On 4/16/22 12:17, Torsten Curdt via Emc-developers wrote:
But this feedback loop decouples the real position from the meant-to-be
position. (expressed in the following error)
And I don't see how the real position could be reported back to LinuxCNC
so
it's still in full control of the movement.
> > > > The splitting would not work for the servos that have the driver
> > > > integrated though.
> > >
> > > Why not?
> >
> > There are no pins to connect to :)
>
> That I should point out, is generally NOT a problem for a CET.
>
LOL ... I agree.
> At least not until one would "fix" that
On Saturday, 16 April 2022 14:33:25 EDT Torsten Curdt via Emc-developers
wrote:
> > > Does that mean it requires 4 inputs per motor? Or would this
> > > somehow be normalized into STEPs and DIRs? Or what does Linuxcnc
> > > expect?>
> > The encoders are quadrature, so the diff is low, but the
>
> > Does that mean it requires 4 inputs per motor? Or would this somehow be
> > normalized into STEPs and DIRs? Or what does LinuxCNC expect?
>
> The encoders are quadrature, so the diff is low, but the splitter could
> easily turn that signal pair into a TTL level signal. In fact, and not
> for
On Saturday, 16 April 2022 13:17:16 EDT Torsten Curdt via Emc-developers
wrote:
> > > But this feedback loop decouples the real position from the
> > > meant-to-be position. (expressed in the following error)
> > > And I don't see how the real position could be reported back to
> > > LinuxCNC>
>
> > Now if the motor has an encoder LinuxCNC could read the position every
> 1ms
> > and make it a host based closed loop system. And I get the appeal.
> > But people are also using LinuxCNC with a BOB and Open Loop Steppers
> > without an encoder.
> > So it sounds like the feedback is missing
On Saturday, 16 April 2022 12:13:37 EDT Torsten Curdt via Emc-developers
wrote:
> > > I can see this to be super useful when there is an external encoder
> > > - so linuxcnc is in full control.
> > > But what's the benefit with e.g. Servos and Closed Loop Stepper
> > > that have their internal
>
>
> > I get the general idea. But I am still a little shy on the details.
> >
> > It sounds on a LPT port setup the host sends every individual step to the
> > port.
> > Now if the motor has an encoder LinuxCNC could read the position every
> 1ms
> > and make it a host based closed loop system.
> > But this feedback loop decouples the real position from the meant-to-be
> > position. (expressed in the following error)
> > And I don't see how the real position could be reported back to LinuxCNC
> so
> > it's still in full control of the movement.
> > ...unless you connect the encoder
On Sat, 16 Apr 2022, Torsten Curdt wrote:
Date: Sat, 16 Apr 2022 18:09:08 +0200
From: Torsten Curdt
To: Torsten Curdt via Emc-developers
Cc: Peter C. Wallace
Subject: Re: [Emc-developers] curious about the ethernet protocol
How come you send the velocity commands and not target positions
On Saturday, 16 April 2022 08:15:56 EDT Torsten Curdt via Emc-developers
wrote:
> > Manual on page 3
> > http://linuxcnc.org/docs/devel/pdf/LinuxCNC_Developer.pdf
> Thanks for that link. I somehow missed those docs.
>
> > NML should work over TCP/IP networks including Ethernet but think it
> >
Le sam. 16 avr. 2022 à 18:15, Torsten Curdt via Emc-developers <
emc-developers@lists.sourceforge.net> a écrit :
>
>
> > Use encoder sending position using external feed back loop for position,
> > following error and display also work as usual.
> >
>
> Could you expand on that?
>
> I assume with
Le sam. 16 avr. 2022 à 17:26, Peter C. Wallace a écrit :
>
>
> Basically just following the LinuxCNC model of having the host be the
> locus of control. This is the basic difference between buffered systems
> like Mach and LinuxCNC. By having the LinuxCNC host be the controller
> you gain a
> > I can see this to be super useful when there is an external encoder - so
> > linuxcnc is in full control.
> > But what's the benefit with e.g. Servos and Closed Loop Stepper that have
> > their internal encoder and control loop?
>
> Sending out position instead of velocity also work.
You
> > How come you send the velocity commands and not target positions? Size of
> > the positioning data I assume?
>
>
> Basically just following the LinuxCNC model of having the host be the
> locus of control. This is the basic difference between buffered systems
> like Mach and LinuxCNC. By having
On Saturday, 16 April 2022 08:15:30 EDT Torsten Curdt via Emc-developers
wrote:
> > ...and 87 years old.
>
> Wow! ...and still going strong on CNC mailing lists :)
Not much else to do, the missus passed from COPD back on Pearl Harbor Day
2020, so I've been alone since. Tested at 147 in 1947, I
On Sat, 16 Apr 2022, Torsten Curdt via Emc-developers wrote:
Date: Sat, 16 Apr 2022 14:15:14 +0200
From: Torsten Curdt via Emc-developers
To: Torsten Curdt via Emc-developers
Cc: Torsten Curdt
Subject: Re: [Emc-developers] curious about the ethernet protocol
The way the Mesa stepgen works
> ...
> How come you send the velocity commands and not target positions? Size of
> the positioning data I assume?
>
> I can see this to be super useful when there is an external encoder - so
> linuxcnc is in full control.
> But what's the benefit with e.g. Servos and Closed Loop Stepper that
On Sat, 16 Apr 2022 14:15:56 +0200
Torsten Curdt via Emc-developers wrote:
> > Manual on page 3 http://linuxcnc.org/docs/devel/pdf/LinuxCNC_Developer.pdf
>
>
> Thanks for that link. I somehow missed those docs.
>
>
> > NML should work over TCP/IP networks including Ethernet but think it is
>
lopers
Cc: Torsten Curdt
Subject: Re: [Emc-developers] curious about the ethernet protocol
> Manual on page 3
> http://linuxcnc.org/docs/devel/pdf/LinuxCNC_Developer.pdf
Thanks for that link. I somehow missed those docs.
> NML should work over TCP/IP networks including Eth
> Manual on page 3 http://linuxcnc.org/docs/devel/pdf/LinuxCNC_Developer.pdf
Thanks for that link. I somehow missed those docs.
> NML should work over TCP/IP networks including Ethernet but think it is
> currently out of order and only work using shared memory buffers.
What's NML?
> Main
>
> The way the Mesa stepgen works currently is basically copied from the
> software
> stepgen component. The host PC sends velocity commands to the stepgen
> hardware
> (a 48 bit DDS) and reads the stepgen current position (all at the nominal
> 1 KHz
> servo thread rate) Then a feedback loop in
>
> ...and 87 years old.
>
Wow! ...and still going strong on CNC mailing lists :)
> Welcome to the list, Torsten Curdt. Enjoy, take care and stay well.
>
Thanks for the warm welcome.
cheers,
Torsten
___
Emc-developers mailing list
Manual on page 3 http://linuxcnc.org/docs/devel/pdf/LinuxCNC_Developer.pdf
NML should work over TCP/IP networks including Ethernet but think it is
currently out of order and only work using shared memory buffers. Try to
get it started using ordinary TCP/IP over ordinary Ethernet network a
few
On Friday, 15 April 2022 19:23:49 EDT Torsten Curdt via Emc-developers
wrote:
> Hey there,
>
> I was wondering the following - and mainly really to understand how
> LinuxCNC works.
> Since I couldn't get a proper answer in the user chat I thought I would
> try here.
>
> IIUC the GCODE
On Sat, 16 Apr 2022, Torsten Curdt via Emc-developers wrote:
Date: Sat, 16 Apr 2022 01:23:49 +0200
From: Torsten Curdt via Emc-developers
To: emc-developers@lists.sourceforge.net
Cc: Torsten Curdt
Subject: [Emc-developers] curious about the ethernet protocol
Hey there,
I was wondering
Hey there,
I was wondering the following - and mainly really to understand how
LinuxCNC works.
Since I couldn't get a proper answer in the user chat I thought I would try
here.
IIUC the GCODE interpreter runs in the non-realtime part. It sends the step
instructions to a card to execute the
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