There are two different tasks you must accomplish in order to properly use the "Arc Transfer" signal.  Wiring and controller configuration. I am using Mach3 and a Gecko G540, so that's what I will show here.

Please note that "Arc OK" and "Arc Transfer" are synonymous.



In order to get the signal from you plasma cutter, you must wire a connector to transfer this signal to your controller/PC. 


Plasma Connector

Here is the cable I made for my Everlast Powerplasma 50s. 

Pins 1 & 2: Arc Start

Pins 9 & 10: Arc OK

Once wired I document the wire colors so I can later wire them to the connector used on the controller.

Here is the cable I made for the Hypertherm Powermax 65.

Pins 3 & 4: Arc Start

Pins 12 & 14: Arc Transfer

Again, once wired I document the wire colors so I can later wire them to the connector used on the controller.


PC and Controller Connector

My controller and CNC PC are both located in the same enclosure.  Here, I am showing the 5 pin connector I use to get the plasma signals into my enclosure.


Pull Up/Down Resistor

The controller I am connecting to is a Gecko G540 controller.  Since the "Arc Transfer" signal is a simple relay closure, I need a pull down resister.  This resistor pulls one side of the relay contacts low and keeps it there until the other relay contact connected to the positive side of your controllers power supply to force it high when the contact of the "Arc Transfer" relay in the plasma machine closes.

I solder the resister between two leads as shown here.

G540 Wiring

I bring in the arc transfer leads into my system via the 6 pin connector mentioned earlier. The two red and black leads are connected to the inside of the connector which corresponds to those connected to the "Arc Transfer" signal on the cable.

The black lead is tied to the resistor jumper we created earlier.

The twisted end of this jumper is connected to one of the input ports of the G540.  In my case, I use terminal blocks inside my enclosure. I connect the twisted end of the jumper to the terminal block that corisponds to  input 4 on the G540.

The end of the jumper that has the resistor installed is connected to V- on my controller power source.

The red lead from the cable connector is connected to the V+ on my controller power source.

Mach3 Configuration

Next, we need to configure Mach3 on how to handle input 4. 

While I don't have a THC connected to this plasma cnc, I will use the THCOn input to trigger the use of the "Arc Transfer" signal. Here its configured to use input 4 on the G540 which is pin 13.

Since the Active Low field is not checked, Mach3 will be looking for a high condition to activate this signal.

When ever the Gcode issues a M03 command, Mach3 looks for the m3.m1s macro and loads that code.

In order to test for the THCOn signal we will use a Do While Not isActive(THCON) loop shown here.

It will check for the "Arc Transfer" Signal 300 times with a small pause in between each check.

If the signal is not detected, a message is displayed and the job is aborted.

In the macro, before the signal is tested, The GetOEMLED(24) tests to see if a TORCH on/off button indicator is on.

We can turn this indicator on or off by hitting the Torch On/Off button shown above. This effectively allows us to manually control the detection of the "Arc Transfer" signal.  But more importantly allows the Gcode to turn the detection on and off.

Going Further

In order to allow the Gcode to turn the Arc Transfer test, two macros need to be created.

The first macro is the M98 macro shown here. Save it as M998.m1s in the macro section for the plasma cnc you are controlling.

This will allow the m98 commad to turn off the test for the "Arc Transfer" signal.

If GetOEMLED(24) Then
 Call DoOEMButton(123)
End If


The second macro is the M99 macro shown here. Save it as M999.m1s.

This will allow the m99 command to turn on the test for the "Arc Transfer" signal.



If GetOEMLED(24) = False Then
 Call DoOEMButton(123)
End If  


You can now use m98 and m99 in code snippets and rules to turn the test on and off.



If you have a THC connected to your plasma cutter, it will most likely control the Arc Transfer detection. You will need to refer to the documentation that came with your THC.