What is the difference between INVERT_Z_DIR 0 and Z_HOME_DIR ? (no replies)

What is the difference between INVERT_Z_DIR 0 and Z_HOME_DIR

I am trying to get the Z axis to move down towards the endstop and print bed when pressing the home buttton in Repetier Host manual control. At present pressing the Z axis home button cause the printhead to move upwards away from the bed. I have inverted the Z axis in the Repetier Host printer settings so that the down arrow moves the printhead down, but this has had no effect on homing. I have also inverted the Y axis in Repetier Host so that in manual control the bed moves forwards when the lower Y axis button is pressed.

All endstop report open from M119

X axis operates normally

// ################ Endstop configuration #####################

#define ENDSTOP_PULLUP_X_MIN true
#define ENDSTOP_X_MIN_INVERTING true
#define MIN_HARDWARE_ENDSTOP_X true
#define ENDSTOP_PULLUP_Y_MIN true
#define ENDSTOP_Y_MIN_INVERTING true
#define MIN_HARDWARE_ENDSTOP_Y true
#define ENDSTOP_PULLUP_Z_MIN true
#define ENDSTOP_Z_MIN_INVERTING true
#define MIN_HARDWARE_ENDSTOP_Z true
#define ENDSTOP_PULLUP_X_MAX true
#define ENDSTOP_X_MAX_INVERTING false
#define MAX_HARDWARE_ENDSTOP_X false
#define ENDSTOP_PULLUP_Y_MAX true
#define ENDSTOP_Y_MAX_INVERTING false
#define MAX_HARDWARE_ENDSTOP_Y false
#define ENDSTOP_PULLUP_Z_MAX true
#define ENDSTOP_Z_MAX_INVERTING false
#define MAX_HARDWARE_ENDSTOP_Z false
#define max_software_endstop_r true

#define min_software_endstop_x false
#define min_software_endstop_y false
#define min_software_endstop_z false
#define max_software_endstop_x true
#define max_software_endstop_y true
#define max_software_endstop_z true
#define ENDSTOP_X_BACK_MOVE 5
#define ENDSTOP_Y_BACK_MOVE 5
#define ENDSTOP_Z_BACK_MOVE 2
#define ENDSTOP_X_RETEST_REDUCTION_FACTOR 3
#define ENDSTOP_Y_RETEST_REDUCTION_FACTOR 3
#define ENDSTOP_Z_RETEST_REDUCTION_FACTOR 3
#define ENDSTOP_X_BACK_ON_HOME 1
#define ENDSTOP_Y_BACK_ON_HOME 1
#define ENDSTOP_Z_BACK_ON_HOME 0
#define ALWAYS_CHECK_ENDSTOPS 1

// ################# XYZ movements ###################

#define X_ENABLE_ON 0
#define Y_ENABLE_ON 0
#define Z_ENABLE_ON 0
#define DISABLE_X 0
#define DISABLE_Y 0
#define DISABLE_Z 0
#define DISABLE_E 0
#define INVERT_X_DIR 0
#define INVERT_Y_DIR 0
#define INVERT_Z_DIR 0
#define X_HOME_DIR -1
#define Y_HOME_DIR -1
#define Z_HOME_DIR -1
#define X_MAX_LENGTH 200
#define Y_MAX_LENGTH 200
#define Z_MAX_LENGTH 120
#define X_MIN_POS 0
#define Y_MIN_POS 0
#define Z_MIN_POS 0

Does anyone have any ideas?

Many thanks