LCTHC sometimes does not respond to voltage changes during the cut

Nacs Fab · Post by **Nacs Fab** » Fri Jul 12, 2019 11:41 am

I have had this system up and running for 7+ years and have had something happening frequently - my LCTHC has a voltage adjustment knob that can be adjusted during the cut. Without touching the knob, I can be cutting a long cut, lets say like the outside of a piece of artwork and all of a sudden the torch may raise while going around and I see the voltage on the digital screen going up and no matter how much I adjust the knob, it does not change anything. If this THC was working I would assume a manual voltage adjustment would change the torch height, correct?

I am using Mach3 with the CandCNC screens, Sheetcam TNG and a Gecko G540 controller with the CandCNC interface board bought back in 2010 or so. I have a Hypertherm 1250 plasma unit.

Post by **weldguy** » Fri Jul 12, 2019 12:21 pm

I am not familiar with your THC system but if your LCD screen is reading the actual arc voltage and not your set point voltage then your THC must simply be malfunctioning. You may only be seeing this on longer cuts since often the THC will be turned of on short cut paths. I am sure Tom will chime in with an actual solution for you. Best of luck.

Nacs Fab · Post by **Nacs Fab** » Fri Jul 12, 2019 12:57 pm

I read another thread below and it mentioned tip saver. I have it disabled in mach, at least on my main Screen, but have it on in the LCTHC setup. I may disable it for a while and see if that stops this issue. Does anyone know if Mach has this setting somewhere else in settings other than the main screen?

Post by **tcaudle** » Fri Jul 12, 2019 4:01 pm

The LCTHC has a test function . The key here is that the voltage is going UP and the same time the torch is moving up so it means that either the preset (target voltage is going up OR the THC function in MACH is off or not working.The THC always moves opposite the voltage in direction . The LCTHC is no longer a CandCNC product. The LCTCH does not feedback voltage to MACH like later DTHC units do so there is nothing for Tip Saver to act on in MACH . All of the settings are in the LCTHC and it only sends back UP and DOWN signals to MACH

LCTHC sometimes does not respond to voltage changes during the cut

LCTHC sometimes does not respond to voltage changes during the cut

Re: LCTHC sometimes does not respond to voltage changes during the cut

Re: LCTHC sometimes does not respond to voltage changes during the cut

Re: LCTHC sometimes does not respond to voltage changes during the cut