THC config that works.

The slow motion is a result of the ARCOK signal going on and off . Set the voltage on the THC correctly and try cutting a thicker metal part so the voltage at the torch is stable for longer periods of time.
What type of THC are you using?
The normal voltage on most of the machines i have and use while cutting 3-6mm thick plates is 113-128 V.
Tom

Ok, so the THC that I am using is my own that I built with an Arduino. Locally I cannot buy a THC so the next best thing was a micro-controller.

According to the Hypertherm manual, I need an arc voltage of approx 112V for a 1.6 mm plate. As far as I can tell, the THC is working correctly, because I can see that LinuxCNC receives the move up or move down signals.

O, so I sort of understand why I should rather cut thicker metals, but I want/need to cut the thinner material.

Regards
Jacob

Hi Tom ; Andy,

I finally got my build to work properly. I do not know whether my solution is the correct method, but it works. I debounced the Arc OK signal with a 100nF cap and that seems to do the trick.

However, I will definitely be ordering a Proma THC or other, because the little Arduino seems to be too problematic and the analog inputs is susceptible to interference from each other.

Regards
Jacob

groblerjf@gmail.com wrote: the analog inputs is susceptible to interference from each other.

The problem you are seeing might be due to the capacitance of the multiplexer. It might help to tie all unused analogue inputs to 0V.

glad you made it work.
Tom

Hi Andy,

So I did tie up all the unused inputs to zero, and there was definitely an improvement. Another guy I talked too also suggested that I install a first order low pass filter on the arc voltage input from the plasma cutter, so I will try that as well to see if I can get and improvement.

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Thanks to all for helping me.