Hypersensing questions

You could possibly do something similar using Ohmic Enable to initiate the probe deployment.

Edit: oops, I didn't see Rod's reply...

Well, it looks like this was a success. The following two plots show

Dry Torch


Wet torch

Goes from about 21 volts to 24 volts so I've set my threshold at 22 volts using mode 1 on my new component

I cut a test part with 48 probes with a wet torch and it did not falter.

Can someone suggest a pin that goes true when we start cutting? I might use that for my relay instead of the is-probing signal? The power supplies take some time to turn on and off so i would be better to turn it on at the beginning of a job.

LittleSparky, you could probably use the float switch feature of Plasmac as it give you a way to set the offsets

Cheers guys. ANd thanks to PCW for coming up with the ideas (and doing the maths!)

So here's what I have now in the control box. Having two terminals on each side of the resistors made it very easy to install.

Actually, looking at that plot, we are getting some rapid changes in the ohmic-on pin at the end of probing. I think I need to revise the component so when the probe turns off, it stays off until the end of the probing event. I'll wait until you guys test and report back!

And this pic shows the amount of water expelled from the torch after pulsing it at the end of a cut

Good deal, always happy to hear good results. My resistors should arrive today, and then I can join the testing party.

On that note, I think I will put my relay back into the circuit becasue a constant current in the torch tip is probably not good for consumables as some electrolysis may occur... Does anyone have thoughts on that?

Can someone suggest a pin that goes true when we start cutting? I might use that for my relay instead of the is-probing signal? The power supplies take some time to turn on and off so i would be better to turn it on at the beginning of a job.

Earlier in the thread, Peter did suggest we use relays to prevent electrolysis as you stated. For that reason, I ordered a nice DIN mounted SSR. I would think we want to stick with the is-probing signal, however maybe it's possible to add a small delay for the first probe? Is the time it takes to power up and produce 24V that significant? I actually thought of leaving the Power supply always powered up, and then breaking the DC circuit instead with a relay. It was suggested to me by one of my EE friends that that would probably be really hard on the power supply. I'm still willing to try it though, as in the end they are ~$20.

I think I need to revise the component so when the probe turns off, it stays off until the end of the probing event.

Without thinking about it too hard (it's 6am here), that seems like a good idea. Comes down, gets a solid trip, turns off so there are no more accidental trips, seems like a good security measure. Alternatively, maybe a longer debounce? Honestly, this is another reason I was thinking of a relay breaking the DC side of the circuit instead of the AC side, as it would be an instant off, instant on.