trigger issues

[oadamo]

hi i have a 3 axis ebay controller and the problem i have is iam using the spindle relay to turn the gun on/off, ive tapped into the two wires off the plasma gun but when the relay fires the gun the control board trips a limit for the e/stop. even if i disable the e/stop in the input setting its still doing it. the relay runs a 12v bulb ok wired to a power supply and ive even tryed running a extra relay but it still trips the control board. i think its down to the feedback off the gun.

anyone no if it is the feed back off the gun or got any ideas how i can stop the feedback off the gun.

[Torchhead]

There is no "feedback" from the torch switch wires. Even if there were it would have to be getting completely through the highly isolated relay contacts into the 12V supply. Most likely a noise or ground loop issue. E-stop is an input that needs to be isolated (with it's own power source and common) and with noise suppression. The table side ground (if you have one) will be really noisy. If that gets into the control logic it will mess up the motion or the inputs.

TOM caudle
www.CandCNC.com