Homing question about: define Z_HOME_DIR

It seems my CNC 'forgets' about Z home.

Z has no end stops. In Marlin config*.h it's: #define Z_HOME_DIR 0

I think there should be 1 or -1 - is 0 correct or should I comment the line out?


#define Z_AFTER_HOMING 0
#define Z_HOME_DIR 0

Z is a balance cam and should stay centered, in the *.h it's written as:

#define Z_MIN_POS 0
#define Z_MAX_POS 59

Would it be better to write like:

#define Z_MIN_POS -29.5
#define Z_MAX_POS 29.5

Controlling software is OpenPnp, which does not give strong Marlin support.

OpenPnp just sends commands to your controller. Homing is handled entirely by your motherboard.

What flavor of Marlin are you running?

In main stream Marlin, the only time when Z isn't homed is when Z_MIN_PIN and Z_MAX_PIN are both set to -1. You'll need to go into the pins_YOUR_BOARD.h file and change these to -1.

Best to leave Z_HOME_DIR set to either -1 or 1.

"It seems my CNC 'forgets' about Z home." Please explain.

I am using nightly Marlin 2.1.x from a few days ago.

The Z axis controls 2 nozzles and at Z0 should be leveled

>>Last image on this page - can't be linked not sure why<<


In `pins_FYSETC_S6.h` I have:

#define Z_MIN_PIN PA0
#define Z_MAX_PIN PA3

Both pins are not further defined in the config*.h

I will test again. with a #define Z_HOME_DIR -1

The original LumenPnP has

#define Z_AFTER_HOMING 31.5

#define Z_HOME_DIR -1

#define Z_MIN_POS 0
#define Z_MAX_POS 59

So Min/Max should be 0-59 or -29.5 +29.5?

When homing in the -1 direction, the Z position is set to Z_MIN_POS when it hits the Z_MIN endstop.

If you want the nozzle position to be in the middle when at the Z = 0 position, then set Z_MIN_POS to -29.5.