The machine is wired as from the manufacturer.  I assume the shield is to ground or a the machine.  The terminations of the conductors are not shielded.  I assume that the machine worked at some point in history as it shows that it actually touched some material. Mach and the are new to the system and the drivers are new OEM.

I will try the following when the shop closes:

Without any change run the 4 1/2 hour carving, if no crash then>

Run the table surface with no changes, then crash or no crash>

Check all obvious connections and strap the machine to a ground rod.

The ground rod is in place as a manufacturers demand to solve issues with another machine.  It didn't make any difference, but we have a ground rod that reaches the center of earth.   

The machine last crashed at about X 45" and 50"

The machine machine position of at approximately X0 and Y0

The DROs are approximately X0 and Y 2.500

Its approximate because I jogged back to the crash site after the attempt to jog home failed.  X and Y are up against the soft limits.  The Y DRO is off by 45" and Y could be off or correct because the operation was a restart with a new Y zero.  However, get this, the skid mark is 2 1/2 inches long.  Remember at the crash X stops and Y/A takes a hike.

I don't recall what Mach was doing during this crash.  On the other I am now biased by the physical evidence and no longer positive Mach was running properly.  I believe on the first one the the G-Code advanced as it should after the crash.

Life was good.  The only thing that was changed prior to the crash was soft limits and CV.  We had change CV several times with no issue.  The soft limits created unexpected results.  That is they were set way over there and the machine would hard stop clear over here.  We did not dwell much on it and set them as they are now.

  

 

      

I am not sure what you are saying. Are you saying the axis take off and Machs DROs show the position they are at when they take off? Or are you saying the DROs show where they should be?
Hood

When I went to the machine I did not pay any attention to the DRO when I attempted to jog towards home before starting the homing process.  In jog the DROs read as described above 0 and 2 1/2 inches.  I was immediately on the soft limits.  That makes the limits off by about 48 inches.  Somebody could have zeroed the DROs  after the crash.

However, the machine coordinates are off by about the same distance.  The machine can't be zeroed in the field or at least nobody around the machine has knowledge or opportunity to make that change.  It appears that the machine coordinates set to zero at or about the same location of the crash. That could explain why the machine stops on X as it believes it is at the limit.  That would also explain why machine Z is off.  Machine Z is off by 1 1/2  inches.  That means machine Z sets to something other than zero.   

Hood,

A heartfelt thanks from across the Pond.  It is a pleasure chatting with someone who gets it.  You may have forgotten that you helped resolve some issues with our plasma table early last year.  Your observations were spot-on.

I am hoping your suggestion of noise is the answer.  I dry ran the table surface code from the last crash forward without a hitch, that is, one hour or double the time between crashes.   I will run it again time permitting.

Absent in the run are the following:

1) Table Vacuum

2) Router motor and its VFD

3) Shop vac dust extraction.

Remember that we ran 4 1/2 hours while carving without a hitch.  The only wild card is the shop vac.  The shop vac was introduced for the table/spoiler operation.  Do you think  static from the vac tube/hose could cause the crash?

I am no expert in noise, in fact I dont think anyone can really claim to have all the answers regarding it as there are just so many variables and what seems to work on one machine may make things worse on another. Industrial machines have for years used much higher signal voltages (24v) for normal I/O and differential signalling for smaller voltage signals (encoders, step/dri etc). That is the best approach but obviously it is not the easiest  to implement on a system that is already built and set up.
 The  common sources of noise are VFD and Spindles, and other motors such as vacuum etc, finding which if any is the problem will just be a case of trying to run without and then introducing one at a time.

Hood

Thanks again

I set out to run the machine again today and discovered the machine coordinates are reading zero.  That is 2.5, 45, and 6 inches from the home switches/machine zero.   I homed X and sent Y home.  I stopped Y to do another task.  I then sent Y home and Mach went to E-Stop because of soft limits.  When I mouse click the Mach reset the Y DRO changes with each click of the reset.  The machine Y coordinate changes the same amount at .001" per click.  The software for whatever reason is resting the machine zero.  Any idea why.  Improper setting or a bug?   

Can you zip and attach the screenset you are using please, it has to be the one from that machine as it may be different from others.
Hood

I believe this is it.

This probably has nothing to do with the problem but I would not use ver 0.066 it has problems. I was running it and experienced strange intermittent issues. I loaded 0.062 and the problems disappeared. If you are using a cheap chinese VFD... they are very noisy in the RF range especially with the carrier frequency set in the lower range.