LinuxCNC M67

M67 is a LinuxCNC G-code M-code that sets an analog output value synchronized with machine motion. The output number is given by the E word (0 to 3 by default) and the value by the Q word, with Q set to 0 turning the output off. The change is queued and takes effect at the beginning of the next motion command, so a motion command such as G0 or G1 should follow it.

Source checked7/7 values · 2026-10-26

Specification

1 source

Language	gcode
Code	M67
Group	Analog Output Control
Syntax	M67 E- Q-
Dialect	LinuxCNC

Parameters

Name	Description
E	Output number ranging from 0 to 3 (adjustable from motmod argument num aio).
Q	Value to set (set to 0 to turn off).

Study notes

The change of the specified output happens at the beginning of the next motion command; if no motion command follows, the queued change does not happen.
Because the output change is queued, a motion G-code (G0, G1, etc.) should always be programmed right after M67.
M67 functions the same way as the queued digital output commands M62 and M63.
The immediate (non-synchronized) counterpart is M68, which sets the analog output as soon as the command is received.
The number of analog I/O can be increased with the num_aio parameter (and digital I/O with num_dio) when loading the motion controller.
M67 will not function unless the appropriate motion.analog-out-nn pins are connected in the HAL file to outputs.

Safety

The E-word output number ranges from 0 to 3 by default; the count is adjustable with the motmod num_aio argument.