Pressbrake CNC Control Setup Questions

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05 Jan 2022 22:20 - 05 Jan 2022 22:21 #230904 by PCW
Could you add a plot of the commanded position?
Does the PID component have index-enable connected?

What is supposed to happen on homing to index is that the when index is
detected, the encoder position is set to 0.0 and index-enable is set false.
LinuxCNC watches the index-enable signal, and when it has a high to low transition,
it sets the commanded position to 0.0 to match the feedback position.

In addition, the PID component watches index enable so that any derivative
or feed-forward term calculations ignore the position step in its commanded and
feedback inputs.
Last edit: 05 Jan 2022 22:21 by PCW.

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25 Apr 2022 19:56 #241246 by andypugh
After recent discussion on the mailing list, can I repeat this question? I would like to see where the problem is.

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25 Apr 2022 21:10 #241252 by EW_CNC
it looks like pid.1.index-enable is false before getting to the index.

 

are the pid connections wrong in the hal file? 

File Attachment:

File Name: bender_2022-04-25.hal
File Size:11 KB


i'll do some more testing.
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25 Apr 2022 21:37 #241254 by EW_CNC
more testing: consistently pid.1.index-enable goes false, but pid.1.command does not set to 0.

 
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26 Apr 2022 00:09 #241257 by andypugh
I have had a re-think, and this version of press.comp might work better. Or, at least, differently.

I am a bit concerned that the behaviour of the brake axis under homing will now be different, though.

if this doesn't work, then try setting the axis home positions to zero ( the press.axis.1.home-offset 50 line) just to see what changes.

reminder: sudo halcompile --install press.comp
 
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28 Apr 2022 01:22 #241424 by EW_CNC
Ok, I did some testing.
Backstop axis: If I starting homing with the home switch true, It moves at search velocity towards positive.
When it moves off home switch true and at the first index it does a very rapid jerk and proceeds with homing and completes homing. (Homing in the opposite direction resulted in a fast rapid move toward positive end of travel, not good!)
Screen Shot:
 
Also this last change causes the position after homing to be 0 right at the index, not at the point of index + home offset.

if this doesn't work, then try setting the axis home positions to zero ( the press.axis.1.home-offset 50 line) just to see what changes.

If I set it to zero homing doesn't work.
I'll keep doing more testing on my end to see if I can give you more info.
Thanks,
EW
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