Powermax 600 THC

[whfabrication]

I've been running a JD Garage diy plasma table for almost a year now and finally got the THC setup for their table. I have a old hypertherm plasma that works great on the table but I'm having trouble finalizing the wiring on the THC. I've looked online at the manual and on the last 2 pages it gives a rough schematic of this machine. I'm having trouble finding the "arc on" signal for this controller to work. I've attached a schematic for this machine to see if anyone has an idea or has figured this out. I've searched other posts and don't see this specific signal being used for the plasma cam setup.

Hypertherm Powermax 600.pdf

[weldguy]

When you say "arc on" signal I am guessing you are looking for what others may call "arc OK" or "ok to move" signal since you have been able to turn the arc ON and OFF and cut parts before trying to install this THC. The powermax 600 does not have any output for "arc OK, or "OK to move" however there should be a way around that. What THC are you working with?

[whfabrication]

That’s correct. I’m looking for the arc ok or ok to move. I’m using the JD garage THC that they sell along with their plasma diy plans. I’m wondering if wire 9 & 10 on the 26 wire ribbon cable labeled OUT A and OUT B would do what I’m looking for and was going to very carefully test that as I know there’s very high voltages in there.

[tcaudle]

You are getting ready to damage your Hyperthemr 600 . Even IF there were an internal arc sense (and there usually is) its NOT the ISOLATED "dry contact" signal you need to feed that THC
true ARC OK is isolated from the internal electronics and its ground
typical outputs of that era and a RELAY with No rally open contacts forming a "switch"/
SOME newer systems use an Opto Isolator and what is called "Open Collector" output that requires you furnish outside DC for it to work
You really don't have many options. If the THC provider has no method to detect current for their THC then the Plasma HAS to have it as an option or you do without it. You can simply short the ARC OK inputs on the THC and "fool" it but it:
1. Will not delay moving as soon as the FIRE signal is sent (not when the torch actually fires)
2 Will not stop motion if you loose arc during a cut.
A crude form of ARC OK is to measure the TORCH VOLTS and that at least holds until the arc tries to start .
That would be a little more complex circuit but it would be better than nothing....
Keep in mind torch voltage is not referenced (tied to) to the internal grounds or anything UNTIL you clip the work clamp to something

[weldguy]

Is there no way to disable the need for an arc ok signal in your thc? Maybe it says something in the manual about that. Many low end plasma cutters do not output an arc ok signal so I would think that would be an option on a universal thc system.

[tcaudle]

All you have to do is short the input (which is all the ARC OK out of the plasma does) and live with it starting motion as soon as the torch fire signal is detected.

CommandCNC has a check box option "Ignore ARC OK" but comes with he same limitations .

The whole idea of ARC OK is to adjust for a system where there is a delay between when FIRE TORCH signal i sent and the actual creation of an ARC that has current flowing. On some Plasma cutters that "delay " can be quiet long (well over a second) so the torch fires after the Z has moved down and even after the XY move start. Not good for the consumables ,

Without the ARC OK you have to either increase the pierce delay times OR you have to manually add in a delay before the Z move from pierce to cut height in the code.

.

[weldguy]

Great info Tom. Hopefully he can make it happen.