PlasmaC torch starting problem (Solved with help from the famous three)

I have a pilot arc start machine the torch will always fire on the first cut but on the next cut it will error out with "valid arc lost program is paused"

Before it errors it does the probe OK the float switch triggers the led and very briefly triggers the torch-on led.

Then pressing pause it will do another cut OK then the same problem happens for every cut.

I have tried altering the OK Low Volts between 5-30 . I notice that after a cut the Ark Volts hover around 2-20v but when the air purge stops is then goes to zero

Vid from my Nas Drive photos.app.goo.gl/aPzSCVR5uQSApnKK6

you need to increase the wait between retry time
maybe your plasma needs some seconds to get a clear refire arc signal

I think bbsr_5a is correct, try increasing the Arc Retry Delay, maybe Arc Fail Timeout needs increasing as well.

Many thanks for the above comments. I will test them out in the morning and will report back.

I think arc retry is set for 1 second

phillc54 wrote:

I think bbsr_5a is correct, try increasing the Arc Retry Delay, maybe Arc Fail Timeout needs increasing as well.

Phill I have tried the arc retry delay to 20 secs with no joy. But thinking about it does the retry delay work for pilot arc.

I have also tried with the arc fail from .5 to 5 secs with no luck.

It always works after an arc fail then the Z goes up and waits until pause is pressed, If I wait until the machine has stopped the air over-run (at this point the volts drop to zero) at this point pressing pause works and completes the cut then I have the same prob at the next section cut.

I am beginning to think this is a problem with the plasma cutter as until the air stops the volts float around anything between 0 to 18 then when the air stops it then holds steady at zero.


Edit: Phil . Trying to test the above I made 3 small circles with shapes and array I saved the gcode to the standard folder and then edited it with G4 P15 after the first cut to see if the 15 sec delay (ie long enough for the air to stop and volts get to zero) but when this was reloaded it purged the g4p15 out of the code. So how can I get a pause in the code between the cuts to test ?

Clive wrote:

Phill I have tried the arc retry delay to 20 secs with no joy. But thinking about it does the retry delay work for pilot arc.

The plasma source should have no effect, the Retry Delay is the amount of time from a failed arc until it attempts to restart the torch. Arc Fail is the time from when the torch was turned on until a failure is reported if the arc is not within the set parameters.

Trying to test the above I made 3 small circles with shapes and array I saved the gcode to the standard folder and then edited it with G4 P15 after the first cut to see if the 15 sec delay (ie long enough for the air to stop and volts get to zero) but when this was reloaded it purged the g4p15 out of the code. So how can I get a pause in the code between the cuts to test ?

That seemw odd, I will take a look later today.

tommylight wrote:

Clive wrote:

I am beginning to think this is a problem with the plasma cutter as until the air stops the volts float around anything between 0 to 18 then when the air stops it then holds steady at zero.

Seems to me that is pretty normal, while the compressed air is passing through the conductivity is higher and the THCAD is sensitive enough to count for that.
Check the ARCOK light while that is going on, if it is ON while the air is still running and the Torch Volts show 0 to 18V, there is most probably your problem, so raise the MIN arcok voltage to something like 60 to 80V.

Thanks for the feedback Tom. I have already tried setting the "OK low volts" to 90v I take it that OK low volt IS the same as min arcok

The plasma source should have no effect, the Retry Delay is the amount of time from a failed arc until it attempts to restart the torch. Arc Fail is the time from when the torch was turned on until a failure is reported if the arc is not within the set parameters.

If I am not mistaken the retry delay does not (BUT i will check in the morning) restart the Z action ie. coming back down for a fresh probe

This is why I would like to put a delay in the actual gcode as a test. That would I think be a good test.

Just for clarity with the gcode I noticed with using shapes that it puts in a G1 X 0.000001 near the end of the code just after a g90 or g91 and if I edit that out and save the file to desktop then reload it it still puts it back in.

I do appreciate all the work you have put into this. Clive