[ Log In ]
[ Register ]
Plasma Sense with the fiber optic cable, ribbon cable and connector to the pokeys57CNC
Plasma Sense with the fiber optic cable, ribbon cable and connector to the pokeys57CNC
Price Options Your Cart
PlasmaSense THC

Control the height of your plasma CNC cutter with a Torch Height Controller (THC) that provides the most optimized arc for cutting. This is the PlasmaSense Sensor that connects directly to Mach3 or Mach4


This is a device that manages the optimum arc while the CNC passes the plasma along the cutting surface of the material. Since material like steel may contain warping and other inconsistencies, the plasma gun needs to be at the right height from the material to have the optimum cutting effect.

This THC solves a lot of problems that may be present in the use of plasma cutting,such as electrical noise. The THC here uses an optical cable that has no electrical characteristics so that the communication from the controller to the THC is clean.

It is recommended that this THC be paired with the Pokeys57CNC controller.https://www.buildyourcnc.com/item/electronicsAndMotors-electronic-component-breakout-Mach4-mach3-USB-ethernet-Board

Included with this package:The PlasmaSense which is directly connected to the plasma machine and communicates back to the Mach3 or Mach4.Two optical cables, one at 2 meters in length and the other at 5 meters in length.

This video focuses only on connecting a plasma torch height controller and configuring Mach3 to use this feature. Prerequisites are that you already connected cables to power supplies, powered your drivers, connected signal wires to the drivers, powered the controller, setup the drivers, configuration,

connected the motors to the drivers, configured mach3 accordingly, and tested the motors to insure they spin when jogged. You will need to motors to function properly to test the output of the THC to see the Z axis spin in both direction to demonstrate the arc voltage guiding the z-axis.

if you haven't done this yet, there are links in the description where you can find videos and instructions how to complete the prerequisites.

The plasma THC that I will be connecting to the pokeys57CNC controller is the PlasmaSenseOut and PlasmaSense , all of these components are linked in the description. the PlasmaSense is connected to the PlasmaSenseOut via a fiber optic cable to isolate the EMI form the plasma torch. I am preparing a 10 conductor ribbon cable to the encoder connector on the controller. These components are a part of the cable pack I sell at buildyourcnc.com, link in the description.

I will use only three of the ribbon conductors, conductors 3, 5 and 7.

On the encoders connector, conductor 3 connects to pin 8 which will be assigned arc up, conductor 5 connects to pin 12 which will be assigned arc ok, and conductor 7 connects to pin 13 which will be assigned arc down

since the ribbon cable is a bit delicate to be directly inserted into the plasmasenseout device, and that the PlasmaSsenseOut device is mounted on a DIN rail, I will be using a cable and connector to connect from the ribbon cable to the plasma sense out. This way, the plasma sense out can live outside of the enclosure to be accessed if needed.

The plasmasenseout device will also need to be powered, so I will be wiring the plasmasense out to the power connector of the controller as shown here.

In this case, the blue wires is connected to pin 8 (conductor 3), the yellow wire is connected to pin 12 or conductor 5, the green wire is connected to pin 13, or conductor 7, the red wire is connected to positive 24Vdc and the black wire is connected to the DC ground.

On the plasmasenseout device, Terminal 6 is positive DC voltage where the red wire will go, terminal 5 is the DC ground terminal and where the black wire will go, terminal 4 is the common terminal and will be also connected to the DC ground with a small jump wire between terminal 5 and terminal 4, terminal 3 is the ARC down terminal and will receive the green wire, terminal 2 is the arc ok terminal and will receive the yellow wire, and terminal 1 is the arc up terminal and will receive the blue wire.

Assuming everything is connected correctly, you can configure mach3. Plug in the power for the drivers, and connect the controller to the computer that contains the mach3 software.

On the computer, start the mach3 software by either starting the mach3 loader and selecting the correct profile, or double click on the mach3 shortcut of the profile you want to use. In this case, I started mach3mill by accident, but it doesn't matter since I am only configuring the pins at this time, but it is best to start with the mach3 plasma profile.

As a sanity check, I am making sure that my motors are functioning properly

to assign the arc up, arc ok and arc down, click on plugin control, then click on the configure pokeys57cnc with the id in brackets. The device settings dialog box will appear. Change pin 8's function to input, and the I/O to Input THC UP. Change the function of pin 12 to input and change the I/O to input THC ON, Change the function of pin 3 to input and change the I/O to input THC Down.

To link the z-axis to the THC, click on the pulse engine settings tab and click on the Up/down signals radio button. You may need to adjust the gain parameter. I set it to 1 in this case.

If you are not in the plasma profile, go into it to test the z-axis movement corresponding to the THC output.

Just to verify that the assignments are still the same, I am checking the pokeys57CNC configuration.

I am loading a file that I created that contains a bunch of random rectangles and circles, enough that can provide enough time to play with the THC.

Make sure the THC button is presses so the green light next to the THC button lights up. Also, press the reset button next to this green light. Press the torch on/off button to turn the torch on. Press cycle start.

If the torch on/off is not on (not blinking yellow), the program will run and the motors will move. If the torch is on, the machine will only move if mach3 gets signals from the plasmasenseout THC that the THC is receiving voltage. The machine will only move if the plasma torch arc voltage is within the constraints for optimal cutting. Because I don't have a plasma torch connected to the THC to sense the voltage, the THC has a test function that will allow you to simulate a voltage.

Once you use the test to simulate the arc up and down, you will notice the machine moving again, and the z-axis will move according to the up and down of the test.

To initiate the test, Press and hold the middle button on the THC until you see the word std, keep pressing the middle button until you see the three letters "tst". once there, you can press the up or down buttons to simulate the arc voltage going higher or lower so the z-axis motor compensates for the arc length.

You will notice that when I pressed the up and down arrows on the THC, the x and y motors started again and you can see the Z axis moving in synchrony with the test up and down.

The plasmasense device is optically coupled rather than electrically coupled to the plasmasenseout device via a fiber optic cable. To connect: Remove the protection tab from the fiber optic connector on the plasmasenseout. Remove the protection at the end of the fiber optic cable. Insert the fiber optic cable into the plasmasenseout fiber optic connector oriented as shown

The other end of the fiber optic cable is connected to the plasmasense device in the same way.

to power the plasmasense, the two terminals next to the fiber optic cable connector will accept 110-220 volts AC (actual range is 95 to 260VAC. The neutral terminal is the terminal closest to the fiber optical cable, and the live terminal is the farthest terminal from the fiber optic cable connector

The plasmasense device is connected to the plasma torch one of two ways, one option is a + and - Hight Volt connection, terminal 1 is the Hight voltage negative and terminal 6 is the high voltage positive. the other option is to connect a divided voltage of + or - 10 volts. The divided positive connection is terminal 3 and the divided negative is terminal 4

Ask a question about the Plasma Sense THC (Torch Height Controller):
Previously answered questions:

Click on the question to reveal the answer.
Related Tutorials
Step 20: Stepper Driver Part 1 - Resistors
This tutorial is dated, if you are considering a CNC for your personal use, we would highly recommend purchasing a kit that is very stable from our wide range of machines available. Well... here we are, finally getting started with the electronics portion of the video series. The entire structure of the CNC machine is complete with the exception of the router mount. We will get to that a little later. For now, we will start on the assembly of the HobbyCNC 3 axis chopper unipolar stepper driver.
Thumbnail: USB Controller wired to one driver and one stepper motor Wiring the CNC Motion Electronics with the USB Interface
Here is a tutorial on connecting drivers and stepping motors to the USB Interface for CNC machines. We offer the USB interface/controller for those that have a laptop, or don't have a parallel port on their computer, and who prefer to use the Planet-CNC software. Here I show a video on the entire process to get your USB Interface connected to the stepper drivers and stepper motors correctly and in a simple and trouble free way.
CNC Electronics Tutorial Image CNC Electronics and Wiring
This tutorial will make you an expert in wiring CNC electronics using a parallel breakout board and standard stepping motors and stepping motor drivers.
Get Help with:
This Product
Tech Support
This Product
Order Query
Tech Support
Not logged in. Log In Register
Track Order(s)
View Order(s)
I Want to Schecule a One-On-One Paid Tech Support Session
Book an Appointment Pertaining to a BuildYourCNC Product (Free)
Ask a Quesion Below (Free):
Book an Appointment Pertaining Other Equipment ($60/half hour)
Book an Immedite Appointment Pertaining Other Equipment ($120/half hour)
Ask a Quesion Below (Free):
Waiting for response... I may not answer immediately, but I was notified on my cellular phone so my response is forthcoming. If I don't respond immediately, you can always go to the [My Account] page to see all of our chats at any time.