strange problem only when torch is on.. help

[lcvette]

Hey guys,

I have started up my 4' x 8' plasma table and it has been running great with the plasma machine not turned on but when i turn on the machine it cuts a few lines and then stops, the reset button in mach starts flashing, and it says that and external emergency stop was called for. I do not have limit switches on the machine and im not sure what else might be causing this issue. if i turn off the plasma machine it will run the program through perfectly. im a bit stumped and as you can imagine this being my first machine i have been super jazzed and am ready to start cutting some parts.

any ideas or suggestions would be greatly appreciated!

Thanks!

Chris

[coherent]

Check all your settings in the software and make sure there's nothing weird or changed in the settings that might cause it to be interpreting a torch on or off command causing the problem. Check any settings for your ATHC if you have one that could cause an issue. Test by turning off that ATHC and trying a short cut if you can.
Also you could be getting interference from your torch cable and unshielded stepper cables. Separate them from each other as well as any other power cables because I've seen shielding (errr, lack of) cause issues.
Last thought is make sure something isn't overheating driver/electronics wise. Hot electronics can cause strange things to happen too.
You didn't say what machine or equipment you have, but different machines, plasma cutters & ATHC's are connected/cabled differently so can't be more specific, but double check all those to ensure they are correct and good connections.
Let us know if you figure it out, others may learn from you findings.
Good luck!

[lcvette]

I have a feeling it is probably HF interference because everything runs absolutely PERFECT with the plasma machine turned off. not sure if my cables are shielded or not, they are from cncrouterparts.com, link to product here:
CNCRouterParts

thought they were shielded but i don't see that written anywhere on the listing. hmmm...

its not temperature, i was paranoid about the G540 and motors and cable getting hot so i have been checking them and they run nice and cool compared to what i have read on here.

the settings couldn't be it, because it runs through the motions perfect when the torch is turned off. the relay is still clicking when the torch is supposed to fire, its just the main plasma machine being on and running when it seems to have a problem.

is there a way to shield the plasma torch cable so it wouldn't interfere? i have it run in the cable tray with the motor wires and would like to keep it there being a 4' x8' table, it can get tricky keeping things from catching and binding something up. I blew my old toshiba board that way and thats when i upgraded to the G540 (very nice unit by the way!).

Any thoughs on a way to shied the torch line is very much appreciated!

THanks again,

Chris

[coherent]

Not sure about best shielding methods. I also have a 4x8' plasma cutter and I have my stepper cables in ingus tracks and the torch cable straight up attached to a sort of elastic cable which is attached above the machine (like a giant rubber band?) That way the torch cable is well separated from the rest and can move without tension with gantry movement. In fact the torch and driver electronics are on different sides of the machine. I know you can get shielding sleeves, tubing, tape etc like this stuff here: EMI Shielding Solutions - The Zippertubing Company
but never looked into the best options. There may even be some diy low cost options which I'm sure a bit of google'ing would reveal.
This site was pretty interesting and explained problems and options: http://www.cnccookbook.com/CCCNCNoise.html

[lcvette]

by upping the debounce I was able to cure the issue. i do not use Limit switches and that seems to be what was tripping. I continued to raise the debounce until it stopped faulting. I will be upgrading to a dedicated CNC plasma machine in the future and I am sure that will cure the underlying issue!

Thanks for all your help!

Chris