Using Mesa Stepgen as spindle but M4 / reverse / ccw does nothing

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29 Mar 2023 01:40 #267754 by snakeoil
I'm not 100% sure what I'm doing with HAL so I apologize! This is probably a simple problem but I'm not sure I understand the plumbing of it.

The UI button for "spindle on" (and MDI M3) works as expected.

M4 however (and the reverse button in the UI) does nothing. Code keeps running but spindle is paused, doesn't move. The manual "reverse spindle" button sort of just makes the UI flash/glitch for a second. And sometimes after some GCode execution the reverse button will be grayed out / disabled altogether.

Here's the relevant part where the spindle is set up. It's driving a simple NEMA 23 open loop stepper.
#*******************
#  SPINDLE - STEPGEN 04 ROTARY AXIS
#*******************

setp   hm2_7i76e.0.stepgen.04.dirsetup        [SPINDLE_0]DIRSETUP
setp   hm2_7i76e.0.stepgen.04.dirhold         [SPINDLE_0]DIRHOLD
setp   hm2_7i76e.0.stepgen.04.steplen         [SPINDLE_0]STEPLEN
setp   hm2_7i76e.0.stepgen.04.stepspace       [SPINDLE_0]STEPSPACE
setp   hm2_7i76e.0.stepgen.04.position-scale  [SPINDLE_0]STEP_SCALE
setp   hm2_7i76e.0.stepgen.04.step_type        0
setp   hm2_7i76e.0.stepgen.04.control-type     1
setp   hm2_7i76e.0.stepgen.04.maxaccel        [SPINDLE_0]MAX_ACCELERATION
setp   hm2_7i76e.0.stepgen.04.maxvel          [SPINDLE_0]MAX_VELOCITY

net spindle-enable          =>  hm2_7i76e.0.stepgen.04.enable
net spindle-vel-cmd-rpm     =>  hm2_7i76e.0.stepgen.04.velocity-cmd
net spindle-vel-fb-rpm         <=  hm2_7i76e.0.stepgen.04.velocity-fb

net spindle-enable => spindle.0.on

# ---setup spindle control signals---

net spindle-vel-cmd-rps        <=  spindle.0.speed-out-rps
net spindle-vel-cmd-rps-abs    <=  spindle.0.speed-out-rps-abs
net spindle-vel-cmd-rpm        <=  spindle.0.speed-out
net spindle-vel-cmd-rpm-abs    <=  spindle.0.speed-out-abs
net spindle-enable             <=  spindle.0.on
net spindle-cw                 <=  spindle.0.forward
net spindle-ccw                <=  spindle.0.reverse
net spindle-brake              <=  spindle.0.brake
net spindle-revs               =>  spindle.0.revs
net spindle-at-speed           =>  spindle.0.at-speed
net spindle-vel-fb-rps         =>  spindle.0.speed-in
net spindle-index-enable      <=>  spindle.0.index-enable

# ---Setup spindle at speed signals---

sets spindle-at-speed true
 
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29 Mar 2023 02:04 - 29 Mar 2023 02:07 #267756 by snakeoil
My first thought after posting this and re-reading the man pages is it's going to be a simple net like this...
net spindle-ccw => stepgen.04.dir

So that the "forward" output bit from the "spindle" "component" is sent to the "dir" bit of the relevant stepgen "component" – is that language right maybe?

But that could be off-by-one... maybe it should be sending the "reverse" bit instead. I'm away from the machine until tomorrow.

Edit: But... then if it's really that simple, wouldn't M4 still be running the spindle, just in the wrong direction? Currently M4 is stopping it entirely.
Last edit: 29 Mar 2023 02:07 by snakeoil.

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29 Mar 2023 08:23 #267782 by andypugh
Is the dir output of the mesa card wired to the dir output of the stepper?

If you use halmeter or halshow to look at the pin values you should see hm2_7i76e.0.stepgen.04.velocity-cmd go negative for reverse rotation.

If it does, then the hardware dir pin should change state.

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29 Mar 2023 12:50 #267803 by snakeoil
That's a good question and where I'm confused. I cannot find any dir output (or input) pins in the docs. There are only these velocity floats which seem to go negative:
spindle.0.spindle-rpm (float out)

From linuxcnc.org/docs/2.9/html/man/man9/spindle.9.html

And then as for output from the MESA stepper this:
hm2_7i76e.0.stepgen.04.velocity-fb (float output)

From linuxcnc.org/docs/2.9/html/man/man9/hostmot2.9.html

What I've been using up to now is essentially just copypasta from old forums posts, which I am trying to reverse engineer. The params that have been working so far aren't in the docs so I'm basically just guessing what to net to what.

Also for anyone reading this the little arrows => don't mean anything and the most of the syntax examples are like `net signal source destination destination` but then the config file generators seem to use the syntax `net signal [optional arrow] [autodetected-in-or-out]`

 

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29 Mar 2023 13:03 #267805 by snakeoil
So using that original config Halshow says:

M3
positive value for stepgen.04.velocity-cmd
true for spindle-cw
false for spindle-ccw
true for spindle-enable

M4
0 for stepgen.04.velocity-cmd
false for spindle-cw
false for spindle-ccw
false for spindle-enable

The full .hal file is attached to original post. That does work but only M3/forward.

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29 Mar 2023 13:06 #267806 by andypugh
Which LinuxCNC version?

Does your INI have a spindle section with a minimum spindle speed in it?

linuxcnc.org/docs/2.9/html/config/ini-co...:ini:sec:spindle-num

(This section has no effect in versions 2.8 and earlier)

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29 Mar 2023 13:07 #267807 by andypugh
And are you using M4 S1000 (or whatever) rather than just a plain M4?

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29 Mar 2023 14:18 #267812 by robertspark

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04 Apr 2023 01:52 #268224 by Mike Connelly
I've just recently run into the same thing and have a thread going here -
forum.linuxcnc.org/49-basic-configuratio...t-no-reverse?start=0

No answers yet, but PCW said he thinks it's something to do with the halui because he's not having M4 problems on a setup that doesn't have halui.

Have you made any progress?

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04 Apr 2023 02:58 #268230 by Mike Connelly
The docs state that if MAX_REVERSE_VELOCITY and MIN_REVERSE_VELOCITY aren't defined they will default to MAX_VELOCITY and MIN_VELOCITY respectively. This doesn't appear to be true, because after I defined those _REVERSE_ values my M4 came to life. The spindle is still turning the wrong direction, but at least it's responding!

Thanks!

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