How to Control a PWM Gripper

i use M68 to control my rc-servo gripper's
so i can control it by gcode and for the gui i use mdi commands and a vcp gui with buttons to set some fixed positions

[HALUI]
MDI_COMMAND = M68 E0 Q-100
MDI_COMMAND = M68 E0 Q-75
MDI_COMMAND = M68 E0 Q0
MDI_COMMAND = M68 E0 Q75
MDI_COMMAND = M68 E0 Q100

www.youtube.com/shorts/Tp3savo-MGs

Please do you have any more details on this?
How do you use the M68 to open?
How do you use the M68 to close?
Do you have M68 (number value)?

www.linuxcnc.org/docs/html/gcode/m-code.html#mcode:m68

See the note about the hal pin.

Looks like meister was using different numbers for different positions
some likely being fully open and some fully closed

exactly, the servo is configured as an analog output and can be controlled with values from -100 (open) to +100(closed).