soft limits different after power cycle

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29 Oct 2017 17:47 #100977 by RayJr
Hi Petr.
Commenting that out seems to have aggravated the resonance like problem. I am back to having the motor freeze up when it gets near the commanded speed.
Going back to open loop by commenting out:
net y-pos-fb <= hm2_5i25.0.encoder.01.position
net y-vel-fb <= hm2_5i25.0.encoder.01.velocity
net y-index-enable axis.1.index-enable <=> hm2_5i25.0.encoder.01.index-enable

and un-commenting:
net y-pos-fb <= hm2_5i25.0.stepgen.01.position-fb
net y-pos-fb => axis.1.motor-pos-fb

seems to eliminate the problem.

I am wondering if my choice of encoder per is grossly too high and causing the stepper module in the 5i25 to be jittery and screwing up the Gecko G202. Encoders are 2000ppr, so with quad counts, it is 4x the steps per unit.

Is there a place I can find documentation of all the pins for the 5i25 presented to HAL, including options for each?
A man page?

"No problem can be solved from the same level of consciousness that created it"

Albert Einstein

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29 Oct 2017 18:27 #100978 by PCW
You very likely have to reduce the P term after removing the PID error limit for closed loop via encoder mode
too much P term is what will cause jiiteryness in the stepgen

I'm not sure I understand what you mean by "having the motor freeze up when it gets near the commanded speed"
The motor should always be running at the commanded speed, do you mean maximum speed?

As far as encoder resolution goes, the higher the better

The hostmot2 manual page has most of the firmware pin names:

man hostmot2


If you change the hal file in that manner you are using open loop mode (so P can go back to being 1000)

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29 Oct 2017 22:26 #100995 by RayJr
Could I be screwing up the PID by feeding it both vel-fb and pos-fb?

Ray

"No problem can be solved from the same level of consciousness that created it"

Albert Einstein

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29 Oct 2017 22:48 #100996 by PCW
vel-fb is a no-op if you have a 0 D term ( and you probably should leave D at 0 )

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30 Oct 2017 02:59 - 30 Oct 2017 03:56 #100999 by RayJr
This afternoon, I isolated the step motor from the machine, set lcnc up for open loop, and tested.
I have a very bad resonance problem!
Now I need to figure out the cause.
the Chineese step motor, or the Gecko G202.

"No problem can be solved from the same level of consciousness that created it"

Albert Einstein
Last edit: 30 Oct 2017 03:56 by RayJr.

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31 Oct 2017 13:22 #101056 by andypugh

s there a place I can find documentation of all the pins for the 5i25 presented to HAL, including options for each?


The manpage (man hostmot2) is also available here: linuxcnc.org/docs/2.7/html/man/man9/hostmot2.9.html

All the manpages are here: linuxcnc.org/docs/2.7/html/

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