ox-cnc

Z-Probe

Inductive probe controls a relay, which shorts SCL (A5) and GND pins on xPro.

Macro: G53 G0 G90 Z-3; G28; G21 G91 G38.2 Z-60 F500; G91 G0 Z2 F500; G38.2 Z-2 F10; G92 Z-5.28; G53 G0 G90 Z-3

Whhat it will do:

1. move to machine top
2. move to probing position
3. rapid move down until probed
4. move up a bit
5. move down slow until probed
6. set 0 offset
7. move to machine top

(Probing positions should be set with G28.1

So the probe is anything that will take pin A5 to ground when it touches your object. The probe position is relative to machine 0. A typical probe command might be G38.2 X20 Y15 Z-100 (in mm mode). You should set a slow feed rate , e.g. F20 (20mm/min). The G38 will move to X and Y, then Z axis will lower to -100 until the probe makes contact with your object, at which time movement stops. Grbl will report the machine position of the probe touch.

Connect a small capacitance capacitor (e.g. 471) between the probe wires to avoid false triggers

Important commands:

• G28.1 - store current location
• G28 - move to remembered location
• G38.2 F50 Z-5 - move Z -5mm until touched
• G92 Z0 - set work coordinate