THC Velocity lock and void lock

The test branch has been deleted.

I pushed a test branch with a similar flow to the flowchart in the expired patent posted above.
github.com/LinuxCNC/linuxcnc/tree/phillc54/void-cross

There are a couple of input pins for adjustments that can be made:
plasmac.kerfcross_period - is the number of servo cycles to sample the voltage, the default is 2
plasmac.kerfcross_slope - is the voltage slope of the threshold, 500 (Volts per second) is the default

Void override % in the Parameter tab changes the level of the threshold as a percentage of the calculated threshold.

There are a few temporary ouput pins for monitoring:
plasmac.kerfcross_change - the voltage change each kerfcross period
plasmac.kerfcross_count - current count of kerfcross cycles for this kerfcross period
plasmac.kerfcross_threshold - calculated threshold voltage

It seems there is a lack of interest in this, are folk not using void lock or does the currently included version work well enough?
 

I never use it, but i did test it a while back when QTPlasmaC was not in use yet, it had some issues, mainly it did activate when it should but it would remain active all the time after passing through a void. Tried different values that did change the outcome a bit but could not make it deactivate reliably.
Personally, it is a nice feature to have but of little use, well i never had a need for it. Still i would leave it as is, and i might be able to give it a go again next week.

The test branch has been deleted, it was not 100% correct.

We are currently working on void locking and when done it will be tested as working for Hyperterm 30XP and Hypertherm65. If it works on other power sources then that is a bonus. There will be adjustable parameters that should make it reasonably flexible.