OLD Lathe conversion to a CNC
- besriworld
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23 Apr 2025 15:03 - 23 Apr 2025 17:11 #326962
by besriworld
Replied by besriworld on topic OLD Lathe conversion to a CNC
Today I ran some more tests. I can now reproduce the issue described in the other thread with 100% consistency. I noticed that when the Z-axis is moving, G96 doesn't seem to be working. I recorded a video showing that the spindle speed doesn't change at all during the movement.
PS. I think there might be something wrong with the HAL configuration. I just noticed that when starting LinuxCNC, I need to go into the calibration settings and re-save the PID values for the spindle (I enter test). If I don’t do that, the PID control is soft– under higher spindle load, it triggers a hold .Also, if I leave LinuxCNC running idle (without running a program) for about an hour, and then start program execution again, the axis movement speed during a G1 command is once again higher than what was set.
PS. I think there might be something wrong with the HAL configuration. I just noticed that when starting LinuxCNC, I need to go into the calibration settings and re-save the PID values for the spindle (I enter test). If I don’t do that, the PID control is soft– under higher spindle load, it triggers a hold .Also, if I leave LinuxCNC running idle (without running a program) for about an hour, and then start program execution again, the axis movement speed during a G1 command is once again higher than what was set.
Last edit: 23 Apr 2025 17:11 by besriworld.
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27 Apr 2025 16:31 #327171
by besriworld
Replied by besriworld on topic OLD Lathe conversion to a CNC
Today I started the program with the axis graphical interface. No change, the problem remains. Could someone check the HAW connections?
this problem also exists : " ... I just noticed that when starting LinuxCNC, I need to go into the calibration settings and re-save the PID values for the spindle (I enter test). If I don’t do that, the PID control is soft– under higher spindle load, it triggers a hold .Also, if I leave LinuxCNC running idle (without running a program) for about an hour, and then start program execution again, the axis movement speed during a G1 command is once again higher than what was set."
this problem also exists : " ... I just noticed that when starting LinuxCNC, I need to go into the calibration settings and re-save the PID values for the spindle (I enter test). If I don’t do that, the PID control is soft– under higher spindle load, it triggers a hold .Also, if I leave LinuxCNC running idle (without running a program) for about an hour, and then start program execution again, the axis movement speed during a G1 command is once again higher than what was set."
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02 May 2025 14:14 #327503
by andypugh
Replied by andypugh on topic OLD Lathe conversion to a CNC
You don't have auto-tuning PID permanently in tuning mode by any chance?
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02 May 2025 17:58 #327516
by besriworld
Replied by besriworld on topic OLD Lathe conversion to a CNC
The HAW show shows that automatic tuning is not enabled.
What can I test? The problem I have is serious.
What can I test? The problem I have is serious.
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02 May 2025 19:14 #327530
by andypugh
Replied by andypugh on topic OLD Lathe conversion to a CNC
There is mention in the HAL of closed-loop steppers. Does this mean that you are closing the position loop in LinuxCNC HAL with encoders and PID (you clearly _are_ doing this) but do you also have closed-loop stepper drivers that also read the encoders?
It is possible that your problem is due to cascaded controllers.
I would be tempted to try a making an alternate config without the DPLL and with the stepgens in position mode, directly driven by motor-pos-cmd. Having a PID in HAL ought to give better results, but if the problem goes away with a more "classic" config then that at least suggests somewhere to look.
It is possible that your problem is due to cascaded controllers.
I would be tempted to try a making an alternate config without the DPLL and with the stepgens in position mode, directly driven by motor-pos-cmd. Having a PID in HAL ought to give better results, but if the problem goes away with a more "classic" config then that at least suggests somewhere to look.
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02 May 2025 20:39 #327547
by besriworld
Replied by besriworld on topic OLD Lathe conversion to a CNC
X and Z operate in open loop .The encoder (X and Z ) is not connected to the PID controller.
I also have protection in the motor driver if it misses a step.
I also checked the spindle pid controller constants in the haw show .All constants entered.
I also have protection in the motor driver if it misses a step.
I also checked the spindle pid controller constants in the haw show .All constants entered.
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02 May 2025 21:24 #327554
by PCW
Replied by PCW on topic OLD Lathe conversion to a CNC
Can you post your hal/ini files?
Might help with more eyes looking at them
Might help with more eyes looking at them
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02 May 2025 23:48 #327572
by andypugh
Replied by andypugh on topic OLD Lathe conversion to a CNC
I found some configs posted earlier in the thread: forum.linuxcnc.org/26-turning/52640-old-...-cnc?start=60#326830Can you post your hal/ini files?
Might help with more eyes looking at them
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03 May 2025 00:21 - 03 May 2025 00:23 #327575
by PCW
Replied by PCW on topic OLD Lathe conversion to a CNC
Ahh, I missed that
As far as the spindle speed changing goes, it would probably be helpful to
disable the PID/feedback, in case there's something odd going on there.
Disable the feedback by setting all PID terms to 0 except FF0 so the
PID component is just a pass through.
Another thing for debugging would be to dump all the hal pins when
things are working correctly and when misbehaving:
halcmd show all > ok.txt
halcmd show all > bad.txt
and post the results here.
As far as the spindle speed changing goes, it would probably be helpful to
disable the PID/feedback, in case there's something odd going on there.
Disable the feedback by setting all PID terms to 0 except FF0 so the
PID component is just a pass through.
Another thing for debugging would be to dump all the hal pins when
things are working correctly and when misbehaving:
halcmd show all > ok.txt
halcmd show all > bad.txt
and post the results here.
Last edit: 03 May 2025 00:23 by PCW.
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