Machsupport Forum
Mach Discussion => Mach4 General Discussion => Topic started by: grivalsky on February 16, 2026, 04:02:15 PM
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I have Mach 4 - hobby, C82 - dual-port multifunction board - torch height control - PlasmaSensOut
I had installed and purchased a hobby license.
Mach4Hobby_Installer-4.2.0.4612
ESS_Mach4_v278.1
The X axis, Y axis and Z axis worked correctly. When I connected and turned on the HC
the signals for the HC come to me and I see them on the screen as the indicator light lights up, but the Z axis does not respond to them. Even though I have the HC switched to manual control, the Z axis does not respond.
I tried everything I could think of but the HC did not work.
I uploaded a new plugin, I did not change anything, I just uploaded a new plugin there
ESS_Mach4_v320
The X axis, Y axis worked correctly but the Z axis does not move at all even when I turn off the HC. At least the Z axis worked with the 278 plugin.
When I put plugin 278 back in, my Z axis starts working again.
1. Can you tell me what changed that made my Z axis stop working after uploading the new plugin. And how do I fix it?
2. Why doesn't my HC work at all?
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Hi,
You may need to assign your up and down pins to THC up and THC down on your inputs. You will also need an ARC OKAY signal from your THC in order for Axis Override to happen.
Basically, with a digital THC in Mach, we need two things. An ARC OKAY signal, and a signal that tells Mach to go Up or Down.
The M3 process is basically just probe, pierce Height, wait for ARC OKAY. If there is no ARC OKAY signal, Mach will fault out. If there is an ARC OKAY, we will continue with the process.
How to Get an ARC OKAY signal:
- Have an ARC
- Have a Digital THC able to read the arc
- Have the Digital THC send the 5-24v to an input on your motion controller
- Once the Mapped signal Activates, Mach will start looking for the ARC UP or ARC DOWN signals to decide to move or not.
Determining up or down with a Digital THC.
Voltage must be within Deadband of your target voltage. If Voltage exists outside of your Deadband, you will have either a THC UP or THC DOWN signal.
Common issues:
If Z is only going up or going down and your ARC voltage is within the Deadband of your target voltage, odds are very high that you have EMI and you will need to find ways to eliminate it.
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The signals from the THC went up and down correctly because I saw them on the monitor when the UP and DOWN lights came on. I also had ARC connected, because when the sheet metal started to wave, the cutting was interrupted because it lost ARC. Similarly, when I simulated the up and down movement on PlasmaSensOut, I saw the signals on the monitor, but the plasma did not respond to them. That's why I wanted to try installing the new plugin ESS_Mach4_v320. I didn't change anything in the configuration, I just installed the new plugin and the Z axis stopped working even in manual jogging mode. I don't understand why? When I uninstalled the new plugin and installed the original ESS_Mach4_v278.1. The Z axis works correctly but does not respond to THC. I also noticed that during cutting I could not even manually correct the Z axis. I don't know if this is correct or not. Then I reinstalled the entire Mach 4 and installed ESS_Mach4_v320. I tried to move only the Z axis so that I wouldn't have to configure the entire thing unnecessarily. With the ESS_Mach4_v320 plugin, I don't want to move the Z axis at all, even in jogging mode.
I don't know if I understood correctly: if no program is running and the plasma is just standing still, I can't move the Z axis using THC UP and DOWN even if I have THC ON turned on like in jogging mode?
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Your M3 command runs a THC ON script. This tells Mach to go through the sequence and then start looking for a up or down signal.
The UP or DOWN signal will only move the Z axis if we have a successful M3 call and a good ARC OKAY signal.
For testing purposes, start off in manual mode and cut straight lines on some scrap material. Use the up or down buttons manually, and this should make Mach do a velocity move up or down. If this is successful, then move to your Digital mode for your digital THC. At this point, the commands are fully controlled by your Digital THC.
If manual mode works but Digital does not, look at your Input settings and make sure your up and down signals are mapped correctly and in the correct polarity.
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Hello
I tried to install Mach4 vs. 5920 and the ESS - 320.
I use the M4_CNC4PC_Plasma_V2 screen
I configured only motor 1 for the Y axis and motor 2 for the Z axis. Signals only step and dir for the motors and limit switch P+ and P- for the end position sensors. Here is the FIRST problem I have.
In manual mode in jogging mode the y axis moves. On the screen I see the change of coordinates and the axis physically moves. On the Z axis I see the change of coordinates on the screen but the z axis does not physically move. If I replace the ESS 320 plugin with the ESS 298 plugin it is the same, the y axis moves and the z axis does not work for me. As for the configuration, I still do not change anything. I upload the ESS 278.1 plugin there in this case the y axis moves as before and physically but at the same time the z axis works and moves physically. If I suddenly put another plugin there, the z axis stops. I don't understand this at all and when I have plugin 278.1 there, the z axis works for me but the THC doesn't work at all, so I wanted to test another plugin.
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What motors do you have mapped to what axis?
Motor0; Not used?
Motor1; Y Axis
Moror2; Z Axis
Motor5; "THC Axis"
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Now I just tested why the z-axis doesn't work for me. I just quickly configured it so I didn't have to do everything. I found out, as I already wrote, that the z-axis only works for me with the ESS 278.1 plugin, which I still don't understand why the Z-axis doesn't work for me with other plugins.
Here I'm sending my motor settings at the moment when I was using the ESS 278.1 plugin. Where all the motors worked and the plasma cut, but the THC didn't work for me.
I've never used it Motor5; "THC Axis"
because I couldn't find it in any manual.
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There's a manual for the plasma configuration in your Docs folder of Mach. I attached it to this message.
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Plasma machine configuration is similar to that of a mill or a router. THC, however, is handled with an
out-of -band motor. For example, if Motor 2 in the profile is mapped to the Z axis, an out-of-band
motor must be enabled and its motor tuning settings must match those of Motor 2. If Motor 5 is used
as the OB motor and axis, it must be assigned as OB1(6)
In the Configure drop-down menu, open the Plasma Screen Configuration panel.
Default THC mode, THC Axis, and the Analog Register will be set here.
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In short, set motor5 to be matching your Z axis Counts per unit, accel, and velocity and map motor5 to OB1 for plasma. If you can't get normal motion out of your Z axis, then you will not be able to get THC motion out of your Z axis. You can start by testing Manual mode to see if you can get up and down commands by clicking. If you can do that, then we could move to Digital.
Do you have other motion controllers or do you just have the ESS?
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Thanks for the help, When I get to the plasma I will try it and write.
I only use the C82 board which controls the drivers for the stepper motors.
I followed this manual which I attach in the attachment.
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I don't understand one more thing. If I define THC as OB1 motor 5, how does he know that it is Z axis motor 2 if I didn't tell him?
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Our THC does something called Axis Override.. It uses a fake or false motor to handle the Jog velocity moves of your Z axis. In rare cases, some may want to have a separate Steps per Unit for their THC. When your THC tells Mach it wants to go up or down, you get this Axis override command to command Z in its stead. All this logic is handled inside of your M3 macro. So when you call M3, it will start looking for the up or down commands after we have ARC OKAY and we get past to the "Cut" Sequence of the torch.
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Do I have to edit the macro somehow? Or is the macro created on OB1 motor 5 and I just need to create motor 5? In the G code program, does the M3 command have to be called somewhere, or does Mach 4 automatically call the macro when the signal from THC up or down comes?
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M3 or M03 is the same as turning your spindle on a standard system.
The same is done for Plasma, M3 or M03 should make the attempt to turn your Torch on.
Once your Torch is on and you have an ARC OKAY signal, your THC should work its magic.
In the configuration side have Motor2 set up as your Z Axis and have Motor5 enabled and setup as your OB1 Axis. Steps per unit, Acceleration, Max Velocity and direction should all be the same between the two motors.
From your TCH, you should have 3 wires coming to your Motion Controller (Sometimes this is a cable.) These three wires should be ARC OKAY, UP, DOWN.
Inside of your Mach Inputs Config, you will have 3 inputs available for THC. THC ON, THC UP, THC DOWN. ARC OKAY is your THC ON, UP is your THC UP, and DOWN is your THC DOWN.
These three signals control your Torch Height after the probing and Torch ON Sequence.
If this is set up correctly and you have the proper target voltage in your THC, you should have no issues with Torch Height.
By default on the plasma profile, you should not have to modify your M3 macro.
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That's what annoys me the most about it. Everyone else does it without doing anything and I don't at all. I tried it now exactly as you wrote these settings and the result is the same. I'm attaching a video and a few pictures with the settings. I had to upload the video to storage because it's bigger.
video:
https://www.uschovna.cz/sk/zasilka/UWLX89CNLFAUWJZM-P39/
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foto 01
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foto2
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Is that the Smooth Stepper Screen?
Also can I get logging data when you do that? make sure that you have all of the options selected for it.
THC controls will not affect your Z axis DRO unless you have a closed loop system. Do you have actual motion on your motors? That would be more of the tell on the Z axis.
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How is logging done? Yes, when the coordinates move as seen in the video, the motors actually move when I jog. It's hard for me to record it all at once in one video because the screen is rotated differently and I can't record a clear video of the movement and the monitor. I'll send you a print screen of all the settings when I get to the plasma. Picture 05,06,07 are the Smooth Stepper Screen settings, Picture 01,02,03,04 are the Mach 4 settings.
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Logging is done by going to Diagnostic → Logging. If you hit the gearbox once the window opens, you should be able to select the Log Categories. Just select all the checkboxes and hit play. This will start recording what happens in Mach.
So only when you directly jog the axis, motor Z moves, if you use your THC, Z does not move.. Is that understanding correct?
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Yes, when I directly jog the axis, motor Z moves, if i use THC, Z does not move.