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Andrew,

Yo don't need the Q255.... (if you want it on 100%)
M10 without the parameter will provide 100% PWM duty cycle.

I should have added to that, it's documented in the uccnc uses manual under the mcodes section

Thank you Rob! I will test it tomorrow.
And if will have success will start testing plugin for THC.

Andrew,

Let's think of 2 different situations - starting a cut with THC off, and starting a cut with THC on.

THC OFF
M3 is issued then XY moves are issued. No harm will come if the torch didn't fire or there was a delay before the torch was "lit". When I say "no harm" I'm more talking about the torch won't raise or dive.

THC ON
M3 is issued. Now imagine if THC control happened immediately without waiting for Arc OK. The THC want to keep the arc volts the same as Set Volts but before the arc is established the volts are much lower. Therefor the THC will raise the Z in an attempt to get the torch volts to increase to the Set Volts level. It does take a certain amount of time for the M3 signal to get to the plasma cutter (via relay, etc), then for the plasma cutter to establish the arc and give Arc OK. In that short time the Z axis would have been raising. Worse still if there was a misfire the torch will just keep raising.

So I THINK that is the basis for waiting for Arc OK when THC is enabled.

Keith.

Keith, you're right, but let's look at this from the other side.
Yes, THC ON/OFF this is "wait for ArcOK" future. It's mean CNC hold XY moves while ArcOK signal from cutter or THC controller is not present. Without main arc no sense to start XY moves. Cut would be incomplete if the arc occurs later - delay between start signal and main arc issue any time up to 5 seconds (depend from cutter). Sometimes you need time for pierce. And of course it's will decrease the lifetime of consumables. Also you have to return torch on the M3 position and restart. It's all take time.

Second basic future - Turn on/off AVC (automatic voltage control) from THC inputs (for example Torch up/down) - just torch freeze when AVC off. So, we need to have ability to control this future from gcode and/or from UCCNC antidive future. I like this future, because it's solve 80% of all problem during cutting.

Andrew, I was having a look at the neuron lite thc manual yesterday, how do you turn the torch on and off, as it looked like you only have one hard wired input from the cnc controller software which is the thc lock function

Is torch on and off via software plugin? (Ethernet connection)

Yes Rob. For torch on/off signal is used software (Ethernet) way. This signal starts the initial height sensing procedure and then main cutting sequence.