In the KRMx02 Upgrade workbook I take you step by step through the process of adding a depth probe to your KRMx02.

In this section I will show you how to connect that probe to the MASSO.


Wiring the Probe

The MASSO expects a V+ signal to activate the probe input.  The problem with that is one half of our prob connection is to the KRMx02 machine and router, which is grounded.

To solve this problem we will add a 1K pull-up resistor between the probe input and the 12V terminal blocks.

This will pull the input high.  When the router touches the probe it will pull it low.

  • Start by soldering a wire to a 1K resistor. 
  • Attach the other end of the wire to the 12V terminal blocks.
  • Cover the resistor with shrink tubing.
  • Attach the open end of the resistor and your probe signal to the MASSO input #6.

Configuring the Probe

You need to add the probe input signal to the MASSO input #6.  You will also need to invert the signal as shown here.

Probe Gcode

The MASSO does not have a builtin probing sequence.  You have to use a Gcode program to actually do the probing sequence.

The code shown on the left is used to tell the probe to move down until it touches the probe plate.

Once it touches the plate it moves up a little then moves back down to touch the plate once more. The difference on the second touch it will be moving much slower.

Once it touches the second time it sets the Z axis offset to the surface of your stock.

I have included the actual file that needs to be loaded on your MASSO thumb drive.

Z Probe

G04 P1000
G38.2 Z0 F30
G04 P100
G92 Z.5
G0 Z.65
G04 P500
G38.2 Z0 F5
G04 P100
G92 z.5
G0 Z3




Starting the Probing Sequence

Hit F6 to access the File Load screen. With your thumb drive inserted into the MASSO you should see a list of files.

Select the "Probe Z" file and hit enter. In a few seconds the program will load.

Once the file has loaded, switch to the Program screen by hitting F2.

Make sure your probe plate is in place and plugged in.

To start the probe sequence run the code by hitting the CTRL + R key.

After a few seconds the probe sequence will start. 


KRMx02 and MASSO Probing Sequence