No Torch Cutting Signal - Please Help!

[yeomansjon]

I have been using my Plasmacam DHC and Hypertherm Pmax 1000 G3 for about 3 years now and have a new problem i've never had before. The machine was running fine on my last project, then sat about a week and when I went to start cutting a new project no different than the 300+ projects before it wouldn't work. When i initiate the cut command, the Plasmacam jogs over to the pierce point, lowers down, and then nothing, the plasmacutter doesn't fire off. Then I get the following error message:

"Torch cutting was not detected. Check wiring, power or turn off option."

In troubleshooting, I put a fresh set of consumables in, made sure all my electrical connections were tight, checked grounding clamp, air pressure, etc. I found the plasmacam moves around the table normally, I can pick a point and make it jog to that point, with 'Cut' disabled, it will follow any cut path normally. When I hit the 'Test' fire button on the pcam controller, nothing, when i click the torch control box on the diagnostics window in the pcam software, nothing. Then I tried the plasmacutter manually and it cuts perfectly normal by hand. So I determined that I simply wasn't getting a cut command signal from the controller to the plasmacutter. With a little online research and hearing about the special Plasmacam torch control cable, I decided that was likely the problem and replaced it with a new one from Plasmacam. I put it in today and wired it up identical to how the last one was wired that had worked so many times, and it didn't fix my problem. I used the new jumper that came with the cable and connected that while the torch was in position and it fired off normally. Btw, I never knew about that jumper, what a handy thing to have, wish i knew about that a long time ago.

So now I'm looking for any advice. Could it be a problem with the Plasmacam controller? Would seem strange if that didn't work, but all other functionality and motion of the Pcam is working normal. Or could it be a Hypertherm problem with the input from the torch control cable? Something else?

I will post this over at the Plasmacam owners community in case there are ideas there but I value the experience I've seen here also so I felt in good hands. Any help is greatly appreciated, thank you all.

[jimcolt]

On the Plasmacam owners community they will have you do some diagnostic checks to determine where you are losing the voltage signal. The connections in the plasma cutter (directly to screw terminals on the main control board) are the same DC power that goes to the electrode and the work cable......so if your torch is firing and cutting in manual mode that voltage is there.

Have you tried attaching the work cable directly to the material you are cutting?

Here is how the DC arc voltage circuit operates:

Plasmacam cable connects directly to the main circuit board.....where it picks up raw arc voltage (negative is the Plasmacam red wire. positive is the black wire) (sounds abnormal as most DC circuits use black for negative, red for positive! Make sure you don't have these reversed!). About 18" from the plasma end of the cable is some heat shrink tubing, under this heat shrink are two resistors that are wired as a 21.1:1 voltage divider.....so they allow the arc voltage divided by 21.1:1 to travel through the cable to the 6 pin DIN plug (plugs into the Plasmacam control box) and this signal is monitored by the electronics and software to control height. A longer arc will produce a higher voltage.....and the height control electronics will move the z axis lower to get to the proper arc voltage based on what you are cutting. Make sure the control box socket and the DIN plug are fully engaged....

Jim Colt

[yeomansjon]

Thanks Jim, I didn't have any instructions when I re-connected the torch control cable, so I just copied exactly how it was setup before which had been working for a long time, I'll make sure again that I didn't swap the wires (spade connectors), i know the red was on bottom and black on top if that means anything but I'm 99% sure it's exactly how it was before. Is it a bad assumption that because the brand new cable made no change that it's not the cable? Any chance the cable Plasmacam sent me was bad? I'll measure the resistance tonight and see if there is anything wrong with either the new or old cable (or both?).

[PlasmaMac]

The guys in Plasmacam's tech department are really good and should be able help out. Give them a call and if you need to have them send you a copy of the video manual (if you don't have it). Pretty much anything that you'll ever encounter with the machine is detailed in the easy to follow step by step video instructions.

The problem usually is always pretty easy to fix. I doubt that your control box and or cables are the issue. If a control box problem arises, it will be really obvious (ie all of the LEDs stay lit or maybe the control box wont turn on) and usually if it is cable problem, the symptoms can mimic a blown control box.

Since the torch is firing normally, it narrows it down quiet a bit:

1. Zip tie on the trigger (this disables a safety feature on the plas).
2. Sometimes the settings get messed with by others; Check the Cutting Signal (usually should set to min 3v to max 12v) in your settings. In the same area in the settings also check that the " wait for signal before moving" box is checked

3. Definitely check the ground clamp. If there is a proliferation of slag build up on the grates, then placing the clamp on the edge of the material that you are cutting is preferred.

Good Luck Brother,

JAG

[yeomansjon]

The repaired controller did the trick and works like a charm. Still not exactly sure why the Trigger Control Circuit fried, but like the Pcam tech support guy said 'It's just one of those things..." Happy to be up and burning steel again. I am now fighting with height control issues again like I was a year ago, but i'm sure i'll get those kinks worked out again.

Thank you all for the help and support, on this and all my other issues.

[PlasmaMac]

The repaired controller did the trick and works like a charm. Still not exactly sure why the Trigger Control Circuit fried, but like the Pcam tech support guy said 'It's just one of those things..." Happy to be up and burning steel again. I am now fighting with height control issues again like I was a year ago, but i'm sure i'll get those kinks worked out again.

Thank you all for the help and support, on this and all my other issues.

Good to hear your up and running!

When you get a chance to call tech again. ask them to email you over nice cheat sheet called "process on setting up height control". This helped my friend that has an older DHC machine from 2001 to calibrate the the arc voltage correctly. I guess had been using his height control totally incorrectly for some time before tech helped him out.

Having a newer DHC2 with advanced HC is completely different expirience because caus it is completely hands off in terms of setting perimeters works flawlessly.

Good luck

JAG

[cwyatt801]

I have the exact same set up as you and I am haveing the exact same problem. I was wondering what control panel you fixed to fix your problem? I am new to plasma tables and could use the help. Thanks

[PlasmaMac]

I have the exact same set up as you and I am haveing the exact same problem. I was wondering what control panel you fixed to fix your problem? I am new to plasma tables and could use the help. Thanks

Plasmacam's tech team are extremely helpful and should be able to figure out exactly what is causing your issue. Also, the video manual that came with your machine has pretty much all of the trouble shooting techniques that you can watch in the comfort of your home. I would definitely look at the step by step video manual if you are new to plasmacam, because there is a lot of great info in it.

Good luck, Brother

JAG