Configuring LinuxCnc to accept my touch plate (also known as a touch-off plate) was not easy. Based on the information form cnczone.com I compiled this overview.

Part 1: preparation

  1. Add Touch Plate to your system
  2. Configure the Pin in LinuxCnc
  3. Verify the basic functionality works

Step 1: the actual touch plate

My system didn’t have a touch plate nor did it have a connection prepared for this. This article is not about adding a touch plate interface to your controller board, but about configuring LinuxCnc to be able to use it. Nevertheless 2 photo’s of my work to modify my controller to accept a touch plate.

 

Driver-board-empty-socket

Driver board with empty connector. Section A is for the limit switches. Section B will contain the wires for the touch plate.

 

Driver-board-full-socket

Section A has the limit switches wired up. Section B has the new wiring for the touch plate.

 

Step 2:  Configure the Pin in LinuxCnc

LinuxCnc needs to know to which (input) pin number of the driver board the touch plate is connected. In my case it’s pin number 13, consult your driver boards manual or other provided documentation to find yours.

Configure LinuxCnc for using the touch plate. Start the Stepconf Wizard.

Select modify your configuration.

Select the existing configuration file.

Press forward on the Basic Machine Information screen.

Press forward on the Advanced Configuration options.

Now you arrived at the Parallel Port Setup screen.

Select the correct pin number, mine is 13, and select Probe In from the dropdown menu (See A). After verifying my setup (See step 3 further down) I found out that I had to invert my signal hence the invert box is ticked (See B).

Step 3: Verify the basic functionality works

It’s important to test the new setup. It’s easy, takes a minute or so and can save you a lot of headache afterwards trying to troubleshoot your setup.

  •  Start LinuxCnc and switch on your cnc

Select Halmeter in LinuxCnc, select the signals tab and look at the Probe In status

So here we:

  1. Select Halmeter in LinuxCnc
  2. Select the signals tab
  3. Select Probe In
  4. Look at the Probe In status

The Probe In status should be FALSE here unless your probe is actually touching. If your probe is not touching and the status is True the you should tick the Invert box on your parallel port setup, see last image of Step 2.

Final check, this is what you should see (watch the screen titled “Hal Meter”):

Halmeter running, probe not touching, result is FALSE

Halmeter running, probe is touching, result is TRUE

2 Responses to “LinuxCnc – Touch plate – Part 1”
  1. […] « LinuxCnc – Touch plate – Part 1 Jun 11 2012 […]

  2. joseph Brown says:

    I want to learn how to program the touch probe to set offset on contour and casting is there a cd with video are a on line school that teach how program a touch probe if you know of a school it would help me a lot thank you for your time and understanding
    from Mr. Joseph Brown

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