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{axis}={constant} erroneously assigning all motors in coordinate system at once
#1
We use Turbo Clipper, and it runs fine. Recently we had a need to assign positions on-the-fly to only two (out of four) axes in a coordinate system. So I wrote the following line in my PLC code:

CMD"&1X=29.5Y=29.5"

I thought this was working fine for several months (it does have the desired effect). Seemingly unrelated until now, we've had several random customers complain that sometimes they were seeing the A and Z axes (not really a cartesian coordinate system in our case) get offset to strange positions. We've been unable to see this happen until last week, when I was told the feature which used the above CMD seemed to cause major problems with motor positioning. The eventual solution for this customer was to re-home both the A and Z axes to correct their positioning, anytime the mentioned feature was used; due to the uncertainty they have essentially abandoned the feature (it is used during a manual-run mode for our machine which isn't usually necessary).

What I found, is that the above CMD seems to also reset the positions of axes A and Z to whatever they last homed to (regardless of their current positions), even though they are not directly called out. I found that even if I simply type for instance "X=29.5" in PEWIN32Pro, the A axis position changes to "90.0" (degrees), and the Z axis changes to "0.0" (inches). These axes should not be changing when I tell the X axis to change!

I have circumvented the problem by writing a short motion program which issues the following command in place of the PLC CMD:

PSET X(29.5) Y(29.5)

This does *not* trigger changes on the un-referenced A and Z axes. We have used this code pattern before, but as it seems a little hacky, I was going for something a little in-line.

Is this a known issue with the online axis assign {axis}={constant} CMD? Is there something that could be set wrong that would negatively affect the online command but still allow the PSET command to be limited to the axes specified in the instruction?
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#2
It should work.

Make sure no motion is in progress when the PLC executes this statement. Also, follow it with a “single loop” WHILE statement to ensure it execute ASAP:

CMD"&1X=29.5Y=29.5"
P99=1
WHILE (P99=1)
P99=0
ENDWHILE

The motion program usage is recommended.
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