Another plasma component...

phillc54 wrote:

Oops, I didn't allow for dividers.

Maybe 50/blah rather than 1/blah

Thanks for that Phill,

That has gotten me much closer to what I was expecting the arc voltage to be based on my old CandCNC system.

It would be handy for others like myself if you could add that fact into the user manual that the first number of the calculation is the divider ratio.

I will do some test cuts tomorrow and report back how I go.

Also it might be handy to add that the base voltage offset is 1/32 of the base 0V- frequency and then it is refined through the arc-voltage-out pin in the hal.

Also do you have a fluctuating number in your DRO? mine keeps fluctuating from 0 to -0.

I probably should not mention this on Phill's thread but if the truth be known, I don't use the scaling features of Plasmac. I have the scale set at 1 and the offset at 0.

I use this component which I think was the first or second one I wrote once I learnt I could talk to Linuxcnc in C.

forum.linuxcnc.org/plasma-laser/32585-scalethcad-component

No Maths required!

I did try and use it but there as a bug back then that prevented me from entering my numbers.

Stefan, also I'd recommend you change your divider setting to be 30:1 which will give you a perfect 10 volt scale at 300 volts so you will have higher resolution in your voltage reading. Thats what I use on my TD 120 amp. Sometimes it overflows, but the THCAD can handle that on its ear and it only happens briefly on piercing when the THC is disabled anyway.

EDIT: And yes, the voltage will fluctuate around 0 so thats not a problem.

phillc54 wrote:

I probably should not mention this on Phill's thread but if the truth be known, I don't use the scaling features of Plasmac. I have the scale set at 1 and the offset at 0.

That's OK Rod, I won't hold that against you.

I did try and the evidence will be buried back about 47 pages in this thread (Thats just a guess, I'll leave you to unearth the evidence!)

@thefabricator03 Here's a calculator
jscalc.io/calc/NTr5QDX6WgMThBVb
I posted this around page 92. Phill still advises we calibrate against our own machine if we can manage it.

phillc54 wrote:

What number did you end up with for the offset?

The figures at this stage are only theoretical and used to get within the ballpark, any allowances for component tolerances then need to be taken out with actual voltage measurements and fine tuning of the two parameters.

Are you using Axis or Gmoccapy?

My offset ended up at 3721.8 and I am using Axis.

What does ohmic probe detected while moving to probe height mean?

I would of thought that once it detects the ohmic probe it would register that it is the top of material.

Another thing that could be added to the user guide is a list of all of the error messages and a description on how to solve them.