Dc servo motor control

Tommy i turned a small pot onside the drive 1/8 turn, now it is silent, still seems to work ok, but im not sure why this could be. 

On other notes, would you have any idea what polarity arc voltage is on the i/o cable for the thcad? I am confused because the work lead is positive on this machine. 

Maybe i will have to test first
 

Ive it wired to the plug but Il leave it unplugged and check with a dvm when i first get cutting. 

When i go through the the pncconf i can select and encoder input as the arc voltage but i dont get a configuration page to setup the thcad. 

Tommy, I have now done a few cuts and got the arc voltage working correctly in qtplasmac. I was a little confused as there was nowhere to configure the thcad in the pncconf but then i realised it is simply set within the qtplasmac interface. 

I have a bigger problem now though, I have damaged 2 of the -10+10v AN outputs! They have got pinned at 13.4vdc, a reset does not change this so something on the board is damaged. Im not sure how this has happened, I have each driver signal ground to the tb5 ground pins and the shield to the cabinet ground. A few digital output have also failed. I have enough output to do but wont if I destroy another AN output. 

Im using a 5v 10 amp meanwell psu to supply to the 7i92 and supplying 5v to the 7i77 through the cable.

For field power I am using the ESAB 28vdc supply, perhaps this could be part of the problem, not sure. Temped to change to 24vdc meanwell.  

I had a cnc4pc ohmic sensor i had spare wired in, the enable relay inside it started to flicker very fast (even when it should have been disabled) this could also  be a cause of my problems. 

I have retained the esab grounding strip and shielding.

The plasma is a ht2000 running oxygen at 200 amps.

Problems seem to happen around times of starting arc.




  









 

     


very messy at rhe moment, i have removed the ohmic sens9r by the time i had too the pictures, it was a cnc4pc one as in link
Sensor

My ohmic sense wire runs into a box above the torch and then is took down with a multicore cable to the main panel, perhaps i should have it separate.

 

I will sort out the daisy chain. The z axis drive is now in the power box also (bottom left) I ended up chaning to a parker oem670t drive, it tuned in good, i can still change to sheilded wires for the drive. 

I will try moving the thcad board.

If needed I can remount and use old computer box, however my problem is damage to the components, not interference, before problem occured cutting preformance was fine. Problem occured while arc was starting. Previous to this the ohmic sensor was going crazy. One thing I had done which could possibly have caused problems was I wired ohmic sensor to the ground point on the gantry, not to the table, the lead from the gantry to the table and ground rod end up at the far away end of the table (8m, 4 vaccum bins linked with eath cable and bolts) to where i was cutting.  I was using quite a high peirce height. Perhaps the arc has found a path through the ohmic wire from the torch cap and back to the electronics that way. I have now run the ohmic ground to the table.