Hypersensing questions

snowgoer540 wrote:

Why not 24K 10W?

I trust PCW. This project was his baby!

tommylight wrote:

snowgoer540 wrote:

Why not 24K 10W?

No need.

Plus he has calculated 3.75 watts and rounded up to 5 so there is enough headroom. (>30%)

Its actually good a couple of water tables got on the bandwagon as I did the initial testing without a water tray..
Also great we have a couple of brands of plasma cutters involved too.

With a bit of luck, Ill have some time tomorrow to work on this.

snowgoer540 wrote:

Ok good! At least we have a solid baseline.

I havent had time today to do any work on the plasma, I was going to use a small wattage resistor as you did here, and not fire the torch. But I think that saves me some testing. Is there a reason you used 22K ohm over the suggested 24K by Peter?

For the hal scope tests you are doing, can you describe exactly what you are doing to test it? I want to make sure I can perform the same tests to reliably test what's going on. I am glad that the resistor takes the sensitivity to a wet torch down. That's a giant step in the right direction in my opinion.

I am still wondering... is that the use case Rod is trying to fix via code, or is he testing something else?

Used a 22KOhm over 24K just because that's what I had. Shouldn't make a big difference except in wattage requirement if you stray too far.

Power = V^2/R so for a 24K resistor at 300V, you get 3.75W required, 4.09W for a 22K

With hal scope I'm running 2 channels. Ohmic-volts on one channel and ohmic-on with the other. Set the trigger based off of ohmic-on and let it capture the data. Or I just keep it on "Rolling" and manually stop the data capture so I can get data before and after the event.

My guess would be that the trade-off is high sensitivity= lower sense current - more susceptible
to leakage from water in torch vs low sensitivity = higher sense current - worse at detecting contact
with dirty surfaces, though this may be improved with a higher sense voltage.

Sorry to sort of but in, but I have been reading through this forum and then many others tonight and there seems to be a lot of negative press around ohmic sensing and water tables. It got me thinking about a whole other way of non contact sensing with say a proximity sensor or some other device completely left of centre. In my research I came across this technology by swift cut. They claim it’s like a feather sense that can sense even the thinnest material and I’d say for 99.99% of cases it would work flawlessly. Could this be a solution or even a technology added into Plasma C to take it to the next level?

Attached is the brochure of the plate sensor and a demo Video , I couldn’t find a good view of it cutting thin material but have seen on Instagram it sensing 1.2mm with no sweat.

If this should have its own topic created let me know and I apologise in advance but I thought most people who would have an interest in this are replying to or viewing this topic.