THC issues

[erik111]

Having some issues with my trucut machine. All of a sudden when the THC is suppose to be on it does not drop down to cut height, it stays at pierce height. Any help would be appreciated

[acourtjester]

What plasma cutter are you using?? What you describe is not part of the THC process. When the plasma fires to pierce the metal there is a signal called Arc Ok (or similar) from the Plasma cutter which is telling the controller the plasma stream is happening. There is a delay in the G-code to allow the plasma to cut through the metal and then it should start to move and stabilize the arc voltage and this is when the THC comes into play.
It seems you are not getting the Arc OK signal so Mach does not move to cut height. If you are running Mach 3 look at the diagnostic page for this signal it should turn yellow. Don't know what if look like for Mach 4.

torch on.JPG (53.63 KiB) Viewed 636 times

torch on.JPG (53.63 KiB) Viewed 636 times

[erik111]

Powermax 65 is my plasma. I will look on the mach 4 screen and wee what it says

[acourtjester]

You should be able to see that signal just by firing the torch manually F5 in Mach 3.
Put a small scrape on the table an position the torch about 0.150" above the metal and fire the torch and look to see the signal Just short bursts nothing long. Check the wiring if you don't see it, from the back of the 65 jack to the controller input pin. If you are using a Proma THC it comes from the proma ARC output (also known as “Arc Okay”) is activated when plasma ignition is
detected. Route and configure for a software input.