Stepper noise with mesa on new install

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05 Jun 2023 17:07 #272949 by steveb48
Hi All,
I have a system which I have repurposed to driver a Sherline Mill. Using their steppers but TB6600 drivers. 
I'm getting noise during steps. I thought it was the handle rattling but it occurs on all axis. I taped the handle to be sure.
If I run G0 X4, G0 X0 repeatedly, it doesn't appear to loose steps with one exception. The first move after Home runs
about 1 inch past where it should. After that, perfect. 

Sherline steppers
TB7600 drivers, 3200 steps / rev, 2 amp currently limit
Servo thread max jitter 152807
Base thread ma jitter 214347 (not great but I didn't have a problem before)

I tried editing the INI file to increase step pulse beyond the 10,000 that pncconf allows but it didn't make a difference. I did set it down to 4000 to see if I was editing the right place and the stepper no longer moved.

Any clues? 
 

File Attachment:

File Name: Sherline_M...6-05.hal
File Size:10 KB
 

File Attachment:

File Name: Sherline_M...6-05.hal
File Size:10 KB
 

File Attachment:

File Name: Sherline_M...6-05.ini
File Size:4 KB
Attachments:

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05 Jun 2023 17:19 #272950 by PCW
I would check:
hm2_7i76e.0.stepgen.00.position-fb (for the X axis)

with halmeter or halshow to see if the
noise is from the drives or LinuxCNC

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05 Jun 2023 18:27 #272961 by tommylight
Power supply, what voltage for the drives?
One thing to check, disconnect one of the motors and measure the coil resistance, high inductance motors will not be good for bipolar stepper drives, and that reminds me, are the motors by any chance unipolar? And is the middle wire separate for the 2 pairs of coils?

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05 Jun 2023 19:01 #272964 by steveb48
Hey Peter. It's been a while.

Perhaps this is 2 problems.

Start LinuxCNC
Home all
Open halmeter and select hm2_7i76e.0.stepgen.00.position-fb
reads 0
G0 X4
reads 4.979041
G0 X0
reads 0.979041
G0 X4
reads 4.979041

The first time after a home, I get a move too far. After that, all is good.
Actual machine tracks these numbers, well as close as I can measure!

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05 Jun 2023 19:06 #272966 by steveb48
Hi Tommy,
Measured 12.14v. It's a 10 amp supply.
The Sherline steppers are indeed 6 wire. They didn't use the center tap and treated them as bipolar.

My experience before was a continual tone while the stepper was running at the same rate. This seem to have a crunching sound occasionally. I have not disconnected the motors but all axis produce this sound. Hmm, I didn't check to see if they produce the sound at the same time.

Thanks,
Steve
The following user(s) said Thank You: tommylight

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05 Jun 2023 19:58 #272969 by tommylight
12V is to low, but still usable with low inductance motors.
Using 24V would be better, but first, the feedback does not look right, so wait for someone with more knowledge about that, then we can see if the voltage is enough to use the machine.

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05 Jun 2023 20:10 #272971 by steveb48
Hmm, I just re-read the spec. Maybe 24 would have been a better choice. Easy test. I have a programable power supply.
www.sherline.com/wp-content/uploads/2018/12/steps_spec.pdf

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05 Jun 2023 20:32 - 05 Jun 2023 20:33 #272972 by PCW
If you get random "thumps" on all moving axis, that is possibly a latency issue.
One thing that may help is to set the DPLL sample time earlier, that is, change:

setp hm2_7i76e.0.dpll.01.timer-us -50

to

setp hm2_7i76e.0.dpll.01.timer-us -200
 
Last edit: 05 Jun 2023 20:33 by PCW.

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05 Jun 2023 20:36 #272973 by steveb48
I saw that on another thread. Can you remind me where to set that? I assume it's the mesa tool but I don't recall its name.

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05 Jun 2023 20:59 #272975 by PCW
Its in your hal file

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