Weird behavior with Scales/Backlash <resolved>

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tblough
Posts: 3102
Joined: Tue Mar 22, 2016 10:03 am
Acorn CNC Controller: Yes
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Oak CNC controller: Yes
CNC Control System Serial Number: 100505
100327
102696
103432
7804732B977B-0624192192
DC3IOB: No
CNC12: Yes
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Location: Boston, MA
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Weird behavior with Scales/Backlash <resolved>

Post by tblough »

So, I turned off the scales and set the X and Z backlash on my machine. I then re-enabled the scales and re-homed the machine. Moving to the center of travels, I set X and Z coordinates to 0. I then MDI'ed a short 10mm move and the move appears to not complete. Note the distance to go readings - those are the same values as the backlash.
IMG_20180328_130248.jpg
IMG_20180328_130255.jpg
I say the move "appears" to not complete because of the distance to go readings and the incorrect DRO display, however, I can issue another MDI command and the machine will move with the same type of result and no error, so the control does not consider the incomplete move an error. If I set the backlash back to 0 on both axis, the moves complets, and the DRO displays expected values.

Do I have something set wrong, or can you not use backlash and screw compensation with scales?
Attachments
report_0711161562_2018-03-28_13-16-36.zip
(4.14 MiB) Downloaded 105 times
Cheers,

Tom
Confidence is the feeling you have before you fully understand the situation.
I have CDO. It's like OCD, but the letters are where they should be.
Centroid_Tech
Posts: 286
Joined: Thu Mar 18, 2010 2:24 pm

Re: Weird behavior with Scales/Backlash

Post by Centroid_Tech »

The entire concept of having the linear scale feedback is that the linear scale will tell the control exactly where the location of the table is without the control having to take any backlash or screw compensation into account. That means that if you are using linear scales as a dual feedback, which you are in your system, your backlash should be set to 0 and the Screw Comp field should be set to N, which looking at your report that field is correctly set to N.
When requesting support, please ALWAYS post a current report. Find out how to take a report from your Acorn, CNC11 or CNC10 system here: https://www.youtube.com/watch?v=Ecvg0VJp1oQ.

If your question is PLC, Macro or program related, please also post a copy of the program or macro as well.

Without the above information we may not be able to help and/or reply until the required information is posted..
tblough
Posts: 3102
Joined: Tue Mar 22, 2016 10:03 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: Yes
Oak CNC controller: Yes
CNC Control System Serial Number: 100505
100327
102696
103432
7804732B977B-0624192192
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
Location: Boston, MA
Contact:

Re: Weird behavior with Scales/Backlash

Post by tblough »

Thanks. I figured "documenting" the mechanical inconsistencies in the system would somehow make it easier on the control. I'll leave backlash settings at 0.
Cheers,

Tom
Confidence is the feeling you have before you fully understand the situation.
I have CDO. It's like OCD, but the letters are where they should be.
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