Re: Torch Height control recommendations
Thanks for weighing in Beefy. So that makes two of us not selling anything! I think there are fundamental differences between a Windows motion controller and Linuxcnc is that motion control requires real time processes. Windows is not a Real time OS. LinuxCNC requires a real time version of the Linux OS. So windows systems run the motion controller in external hardware (think smooth stepper or UCCNC) but LinuxCNC always runs the motion controller on the PC which has infinitely more resources in terms of memory and CPU processing speed than external hardware ever can.
So if Linuxcnc can read the torch voltage, it can use its resources to manage the THC function at the motion control level using the powerful PID modules available natively inside LinuxCNC. The simplest solution to read torch voltage is to use a voltage to frequency converter and send the frequency to a LinuxCNC encoder input and decode the voltage internally. This can be done via a parallel port and an available software component or using an encoder hardware encoder input on a Mesa card. The THCAD is available at such a rock bottom pricing (USD $69) and designed for the nasty plasma electrical environment, there is nothing else in its class. Using an external card with an encoder input (like the Mesa 7i76e or 7i96) gives much higher performance for both software step gen and encoder reading.
So the tight integration with the motion controller and the torch height control means a LinuxCNC system for plasma becomes much more than the traditional model where the THC is an external black box. The traditional black box has to do the best it can without knowing the full picture whereas with Linuxcnc, the THC function becomes a small part of the all knowing all seeing overall motion control system. So putting this together means that the LinuxCNC Plasmac system becomes a complete plasma controller, not a THC.
Its just a shame that clever people like Beefy can't be convinced to cross over to the dark side to joint those who willingly give up their time to provide 24/7 support from all parts of the globe.
Rod Webster
www.vehiclemods.net.au