Need Help - Strange behaviors <communication errors>

[lavrgs]

I was just jogging my z axis down and it did not stop

I am try to determine why a boss programmed to cut 1.518 is coming in oversize. I used the center finder to locate the hole and ran a program to cut the ring. I placed the center finder back in, to locate the hole, and x was 0.016 off from original, Then I reset zero and move off the hole and came back to 0,0 . As I was jogging down the z axis ran away and crashed the center finder. I apparently have a bigger problem than I thought. After spending that last day chasing axis accuracy I am frustrated and not sure where to start...again

[cnckeith]

run aways are almost always related to axis motor/drive issues. What make model of axis motor and drives are being used? and lets see how they are wired.

[lavrgs]

I have new DMM 0.75kW motors with DYN4 drives. They are wired with factory cables via the screw connectors on Acorn.
Are there any built in troubleshooting options for acorn? Should I go back and use the DMM program to tune motors?

[cnckeith]

drives like these will run away when the encoder signal has issues. start looking there.

[lavrgs]

I'm wondering if we're chasing the right thing. It's conceivable that a sticky mouse could cause the problem. I'd like to do something to get a higher level of confidence...and I don't know how I would analyze the encoder signal. Would that contribute to the out of spec cuts? based on single axis moves I appear to be going the distance called for but when cutting (under load?) I seam to have issues. I need some kind of a step by step process that I can follow to eliminate potential problems. Do I have noise issues - how would I know. I have some basic tools to check measurements and an oscilloscope and time 9-) ... well a little

[cncsnw]

Did it "run away" at exactly the same jog rate you were jogging at? Or did it run away at something faster than normal Fast Jog?

Did the DRO continue to count as it ran away?

[lavrgs]

Did it "run away" at exactly the same jog rate you were jogging at? Or did it run away at something faster than normal Fast Jog?

Did the DRO continue to count as it ran away?

In hindsight I should have been in incremental mode to keep from crashing. I was trying to hit the estop so I took my eyes off the screen so I didn't see the DRO. It continued jogging at the same rate. I have had this happen before,on the z axis, but I was high enough that I didn't crash.
I've got a call into DMM to see what they suggest

[tblough]

The DRO is important. If the DRO continued to change during the movement, then something is happening with the Acorn or the computer - like a stuck mouse. If the DROs were not changing during the move, the it is a problem with the motors or drives.

[cncsnw]

I was trying to hit the estop so I took my eyes off the screen so I didn't see the DRO.

Understandable.

You may be able to tell after the fact, by seeing whether the final number on the DRO makes sense for the final head position; or is more in line with where the head was when the runaway began.

It continued jogging at the same rate

That points toward a stuck-mouse condition (in which case the DRO would have continued to count down as the axis moved).

[martyscncgarage]

Please follow this post and provide the information in it: viewtopic.php?f=60&t=1043
Otherwise we are just taking a guess which is no good for you.
We can not "SEE" what you "SEE" we have no idea how your machine is configured, what your control cabinet looks like, what you are using to jog the machine, whether or not you followed everything in the Acorn installation manual: https://www.centroidcnc.com/centroid_di ... manual.pdf

Please take the time to provide better information and we can provide better more helpful suggestions.
Marty