THC not moving Z height

[Lancer]

Hi, I have a homebuilt table based on Pokeyscnc57 controller with matching stepper drivers and a Pokeys PlasmaSens THC I also have a Pokeys Plasma Sens out THC. My big issue is neither THC will adjust the torch height. I have logged a support ticket with Polabs and sent screenshots of my settings in Mach3 and there plugin. The only reply from them is "have you turned the THC on" has anyone else had this ? Due to both THC's giving the same issue I`m thinking its a Mach3 issue but I have triple checked the documentation and followed the setup guide to the letter.

[acourtjester]

There are a few things that Mach needs to fully use a THC. I have no experience with your electronics but the THC I have used had a test function that help to check the circuits. You need to have the 3 signals from the THC connected to your BOB input, and this box to be checked.
In the test mode you do not need the Plasma working, you can look at the Diagnostic page in Mach to see if the THC signals are lighting up. It may show the ARc OK on and the up/down flash as they change in the THC output. The Z may move during the test if so make sure the Z direction matches the up or down light.

THCa.jpg

Mach THC.JPG

[Lancer]

Hi Thanks for the pointers, Ive tried all the above and a lot more and still nothing. I`m two weeks into a support ticket with Polabs and they have been absolutely useless in responding. I have a demo of Mach4 and it works fine so there has to be an issue with the Pokeys plugin in Mach3. Its a shame because the Pokeys solution is a really nice one but let down but non existent support.

[acourtjester]

That is a failing of many business it seems great before you buy, after, are you talking to me, I can't hear you. They spend lots on the sales department and very little on tech support, if any. It seem many are just resellers of products with no follow up. On one of the early tables I built the BOB was not setup for Plasma and I could not get it to work, you may be in that position. Google questions about Pokeys and plasma to see what comes up.

[nola504]

Lancer, did you ever get the pokeys57cnc and plasmasens working? I just finished my first cnc build with and I used the same equipment. I can't get the THC to do anything. I can run g-code with THC off, but when I turn THC on it just strikes and arc and sits there waiting for something.

While cutting with THC off the system doesn't show tip voltage either. I'm assuming that's an input from the 1:50 connection and it should be continuously refreshing.

[acourtjester]

If you fire the torch and it doesn't move it is waiting for the Arc OK signal, some of the software will not work in the demo mode for the THC.
Does your unit have a test mode, if you you should be able to see the signals input in Mach.

[nola504]

No test mode that I can tell. Plasmasens is supposed to take tip voltage and do some sort of comparison to trigger the ARC OK. It's clearly not doing that. I don't see TIP VOLTAGE registering during test cuts so I need to figure out why that signal isn't getting to MACH3.

My plasma machine has an Arc OK output. I'll wire that into the pokeys57cnc as a plan B.

I wish Pokeys would just make one video of their products being installed and running. Doesn't seem to much to ask for.

[nola504]

Update:

My 1:50 signal was backwards so it was reading a negative voltage. So now it registers the TIP VOLTAGE, but now the issue is that it only starts to read it after I abort a program.

Example:
Run program -> machine touches -> arc starts -> waits for arc okay
At this point no TIP Voltage is being read. It just stays at 1v.

I abort and then I can see the values of the tip voltage spike and then go back to 1v.

Tomorrow I will try to wire it to raw voltage and see if that changes anything. I have an option of 1/50 or raw as inputs on the plasmasens.

[nola504]

Update:

I couldn't sleep so I rewired the THC to raw voltage. Same situation. It only momentarily registers tip voltage while the torch is turning off. I attached a multimeter to the THC during a test cut and can read the voltage. Mach3 just isn't getting the data during the cut.

[acourtjester]

When I looked at the manual for the electronics you have, there seemed to be a configure plugin file which is for the communications between Mach and the board. See attached image, it shows the config plugin in Mach where it shows if the plugin you need is loaded. The arrow shows when I was using the UCCNC ether card on one of my tables. Not sure if this will work but if you hook a small AA battery to the 50:1 input it may show 75 volts on the display. Check in Mach for the Arc Ok and the up/down pins configuration be sure you do not have any of those showing a emulate key, that will override the input signals from the Poky.

mach config.JPG

mach config2.JPG

[nola504]

WOOT! I'm getting somewhere!!!

I have been cutting a simple sample cuts this entire time. A 2.5x2.5 inch square with a 1-inch hole in the center.

Last attempt:
run g-code -> goes to start position and touches off with floating head -> starts pilot arc and just sits there -> I cycle the Torch on/off button in mach3 and it continues on like normal (missing half the circle)

But here is where things change. When it goes to start the square it fires and goes and the THC is working! For some reason it's not getting an arc OK signal after the initial touch. Code is below. Any idea?

N0010 (Filename: Part1 lower pierce height short delay.tap)
N0020 (Post processor: Mach3 THC with scriber.scpost)
N0030 (Date: 15/09/2021)
N0040 G20 (Units: Inches)
N0050 F1
N0060 G53 G90 G40
N0070 (Part: Part1)
N0080 (Operation: Outside Offset, 0, T1: Mild Steel 11GA/0.125 35AMP 55PSI)
N0090 G00 X1.4016 Y1.5827
N0100 G28.1 Z0.12 F19.685
N0110 G92 Z0.0
N0120 G00 Z0.5291
N0130 G92 Z0.0
N0140 G00 Z0.0600
N0150 M03
N0160 G04 P0.2
N0170 G01 Z0.0591 F150.0
N0180 G02 X1.5827 I0.0905 J-0.0905 F88.0
N0190 I-0.3327 J-0.3327
N0200 Y1.4016 I-0.0905 J-0.0905
N0210 M05
N0220 G00 Z1.2500
N0230 X2.6287 Y2.4477
N0240 Z0.0600
N0250 M03
N0260 G04 P0.2
N0270 G01 Z0.0591 F150.0
N0280 G02 X2.4477 I-0.0905 J0.0905 F88.0
N0290 G03 X2.2500 Y2.5295 I-0.1977 J-0.1977
N0300 G01 X0.2500
N0310 G03 X-0.0295 Y2.2500 I0.0000 J-0.2795
N0320 G01 Y0.2500
N0330 G03 X0.2500 Y-0.0295 I0.2795 J0.0000
N0340 G01 X2.2500
N0350 G03 X2.5295 Y0.2500 I0.0000 J0.2795
N0360 G01 Y2.2500
N0370 G03 X2.4477 Y2.4477 I-0.2795 J0.0000
N0380 G02 Y2.6287 I0.0905 J0.0905
N0390 M05
N0400 G00 Z1.2500
N0410 X0.0000 Y0.0000
N0420 M05 M30

[acourtjester]

Arc Ok does not originate from Mach or the G-code but from the plasma unit or the THC unit. What plasma unit are you using, it may call it something else but whenever there is a current path from the torch electrode and the work lead you will have the Arc Ok signal out of the Plasma unit or the THC.
Now some THC units will have an output if it sees a plasma voltage, this is why you can use the raw voltage output. Either will stop if the plasma stream is not flowing (no arc). You can run without arc ok, if mach is not looking for it. Also if you are cutting and run off the metal (or over a hole) the plasma unit will stop due to no current flow (no arc). Your G-code will run through the motions with the plasma unit off as it does not look for an output (arc OK). You really need to verify that the THC is working by looking at Mach's diagnostic page at the torch up and down signals and the Z DRO.
The Z DRO should move around, It may be slightly and the signals for the up and down should alternate.

mach 1.JPG

[nola504]

I'm very close to throwing in the towel with Pokeys equipment. I might run with no THC until I upgrade to a Mach4, ESS and warprunner. What are your thoughts on that equipment?

So frustrating.....

[acourtjester]

Well I have only limited experiences with Mach 4, it is a big change (configuring) over Mach 3 and I did not like it. The other equipment I have no experiences with so no comment. I have used UCCNC which is a good setup, now I have a Price THC connected with it. Will the Plasm Sens work with the electronics you are looking at. I would see if other members chim it on your selections, I know from slogging through the jungle on your own can be a chore. In building the tables I have I have used different electronics and software, some seem easier than others. I am currently working through LinuxCNC, I have things functioning but it has not been smooth. Without the great (did I say GREAT) help from members here and at the LinuxCNC blog I would have been dead in the water.

[nola504]

I took the whole system back apart so I could paint the frame and build the cabinet for the controller. While doing so I triple checked everything. I found that the power supply going to my pokeys57cnc wasn't putting out 24v. It was only putting out 4ish.

I ran a couple passes and I think that was it. I only had a chance to make 2 runs but it detects arc OK and is moving the Z-axis. I'll report back in 2 weeks after the system is put back together.

Thanks again for all the help.

[acourtjester]

Well congrates, Makes you feel good when you find a reason for your problems. Your reply helps others down the road, this will be available with the search function in the upper right for those that look. That may be a quicker solution than waiting for a member reply to their question.