Ok so I have been eagerly awaiting the delivery of my new plasma torch, while waiting I have been extensively testing and debugging my new DIY cnc table and it was all going very nicely.

The torch came this morning so i moved the table into my test area, connected up the ground clamp and powered the system up.

All went ok, placed a bit of test metal on the table, moved to take a test fire and triggered a quick pierce signal, no cut just a quick pierce.

That went ok so i went to move the torch back to start position for a cut test, the torch would not move so i pressed the estop and restarted, z axis started moving and partial x axis but not Y.

Killed the plasma supply and reloaded Mach.

Now it was jumping about randomly as i turned the MPG knob on the pendant and kept throwing "e-stop requested" errors.

Thinking it might be my cheapo crap pendant, i unplugged it, turned off "run macro-pump" and disabled support for modbus/mpg.

Then i reloaded Mach and tried again, now it sort of moves but the DRO's are moving like 20mm for every mm moved.

Pressing home all, would bring the axes to home but then back off at 1% speed or very slow at least.

It would also still throw the e-stop requested errors.



Now, having spent a lot of effort hardening the table against RF, I cant believe I have fried it with a two second pierce?
No other PC's in the area showed any sign of problem and there was no radio interference.
This was just a quick pierce at half power.

Any suggestions at all?
I'm desperate.

Have you got the correct steps per unit set?
Hood

Yes, the table has been running a felt tipped pen for a good few weeks, perfectly at various speeds and has not so much as dropped a step!

I even tested it before firing the torch and all was well.

You said you had reinstalled Mach and after that a 1mm move showed 20mm, that suggests  the steps per unit are incorrect.
Hood

My profound apologies, I meant restarted NOT reloaded mach, I have not reinstalled it yet.

Everything was fine and calibrated very nicely.

Ok in that case then it sounds like maybe you have damaged something. Hard thing to check if all axes are acting weird as you can not swap out drives or pins on BOB. If you have a scope you could check the output pulses from the port to see if they correspond to the pulses set in motor tuning.
Hood

Are these pulses in the kHz range ?

I have a slow scope, not digital, I think its DC to 5mHz possibly.

just been messing about and noticed that there is an LED on the BOB, this is on normally, but after running the axes up and down manually a bit, the LED flashed off then on and Mach threw the e-stop requested error, after that the torch relay will not trigger and the axes start messing about.

I really can't believe I've fried a BOB or the PC surely?

If that is the case then there is little hope of success as I have done almost everything I can to shield this stuff, I have not driven a ground rod yet as its in the factory at work and i doubt the landlord would appreciate that

I could understand it if I hadn't connected the plasma ground lead or something else stupid but I even checked it with a meter first!

The frequency will depend on the commanded feedrate and the steps per unit set.
For example if you had the steps per unit set to 1000 and you commanded a feedrate of 100mm/min then the frequency of that move would be (1000 x 100)/60 =1666.666667 Hz or 1.6KHz

The reason I say that you may have damaged something is that you say it started just as you fired the plasma for the first time. If you have everything connected as it should be then it is unlikely you have damaged hardware but if you have a ground connected wrong or something like that then it is a possibility.
 If you have not fried something then I do not know what the issue could be seeing as it was working fine until you fired the plasma.
You could shut Mach down and run the driver test to see what it looks like. Also have a look on the Diagnostics page in Mach and see if the frequency is steady and close to the kernel you have set, also see what the Time in Int is, again on Diagnostics page.


Hood

Diagnostics show the freq as around 28,048 and time in int as +5 to +6 varying.

I need to ring the suppliers to find out what that LED actually means, when that goes off is when the problems arise, I thought it was a power LED, in that case it might be the PSU?

The mach driver test still passes as "Excellent", nice and smooth on the graph.

Spoke to the BOB suppliers, seems the BOB is fried 100%. (:

The LED is the output from the onboard regulator so its turning itself off randomly.

They also said it was wired wrongly, I had the BOB supply fed from the Z-axis output of the motor PSU, apparently that is bad and must be a separate regulated supply for the BOB only.

Anyone know anything about this?