Auto Bed Leveling RC8 - Z axis goes up while homing

Hi,
I have a problem with the auto bed leveling feature. The z axis goes up when I'm homing z. So the inductive sensor (LJC18A3-H-Z/BX) goes away from the heated bed.
The motor direction is correct, because going up in octoprint drives the z axis up and vice versa.

It's like the printer "thinks" that it starts lower than the bed. Because when I put something under the sensor it goes up another 15mm and than stops (like it should).

Can someone help me please.

// Mechanical endstop with COM to ground and NC to Signal uses "false" here (most common setup).
#define X_MIN_ENDSTOP_INVERTING true // set to true to invert the logic of the endstop.
#define Y_MIN_ENDSTOP_INVERTING true // set to true to invert the logic of the endstop.
#define Z_MIN_ENDSTOP_INVERTING false // ABL // set to true to invert the logic of the endstop.
#define X_MAX_ENDSTOP_INVERTING false //true // set to true to invert the logic of the endstop.
#define Y_MAX_ENDSTOP_INVERTING false //true // set to true to invert the logic of the endstop.
#define Z_MAX_ENDSTOP_INVERTING false //true // set to true to invert the logic of the endstop.
#define Z_MIN_PROBE_ENDSTOP_INVERTING false //true // set to true to invert the logic of the endstop.

//===========================================================================
//============================= Z Probe Options =============================
//===========================================================================
// @section probes

//
// Probe Type
// Probes are sensors/switches that are activated / deactivated before/after use.
//
// Allen Key Probes, Servo Probes, Z-Sled Probes, FIX_MOUNTED_PROBE, etc.
// You must activate one of these to use Auto Bed Leveling below.
//
// Use M851 to set the Z probe vertical offset from the nozzle. Store with M500.
//

// A Fix-Mounted Probe either doesn't deploy or needs manual deployment.
// For example an inductive probe, or a setup that uses the nozzle to probe.
// An inductive probe must be deactivated to go below
// its trigger-point if hardware endstops are active.
#define FIX_MOUNTED_PROBE //ABL

// The BLTouch probe emulates a servo probe.
// The default connector is SERVO 0. Set Z_ENDSTOP_SERVO_NR below to override.
//#define BLTOUCH

// Z Servo Probe, such as an endstop switch on a rotating arm.
//#define Z_ENDSTOP_SERVO_NR 0
//#define Z_SERVO_ANGLES {70,0} // Z Servo Deploy and Stow angles

// Enable if you have a Z probe mounted on a sled like those designed by Charles Bell.
//#define Z_PROBE_SLED
//#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.

// Z Probe to nozzle (X,Y) offset, relative to (0, 0).
// X and Y offsets must be integers.
//
// In the following example the X and Y offsets are both positive:
// #define X_PROBE_OFFSET_FROM_EXTRUDER 10
// #define Y_PROBE_OFFSET_FROM_EXTRUDER 10
//
// +-- BACK ---+
// | |
// L | (+) P | R <-- probe (20,20)
// E | | I
// F | (-) N (+) | G <-- nozzle (10,10)
// T | | H
// | (-) | T
// | |
// O-- FRONT --+
// (0,0)
#define X_PROBE_OFFSET_FROM_EXTRUDER -40 //ABL // X offset: -left +right [of the nozzle]
#define Y_PROBE_OFFSET_FROM_EXTRUDER -5 //ABL // Y offset: -front +behind [the nozzle]
#define Z_PROBE_OFFSET_FROM_EXTRUDER 0 //ABL // Z offset: -below +above [the nozzle]

// X and Y axis travel speed (mm/m) between probes
#define XY_PROBE_SPEED 8000
// Speed for the first approach when double-probing (with PROBE_DOUBLE_TOUCH)
#define Z_PROBE_SPEED_FAST HOMING_FEEDRATE_Z
// Speed for the "accurate" probe of each point
#define Z_PROBE_SPEED_SLOW (Z_PROBE_SPEED_FAST / 2)
// Use double touch for probing
#define PROBE_DOUBLE_TOUCH //ABL

//
// Allen Key Probe is defined in the Delta example configurations.
//

// *** PLEASE READ ALL INSTRUCTIONS BELOW FOR SAFETY! ***
//
// To continue using the Z-min-endstop for homing, be sure to disable Z_SAFE_HOMING.
// Example: To park the head outside the bed area when homing with G28.
//
// To use a separate Z probe, your board must define a Z_MIN_PROBE_PIN.
//
// For a servo-based Z probe, you must set up servo support below, including
// NUM_SERVOS, Z_ENDSTOP_SERVO_NR and Z_SERVO_ANGLES.
//
// - RAMPS 1.3/1.4 boards may be able to use the 5V, GND, and Aux4->D32 pin.
// - Use 5V for powered (usu. inductive) sensors.
// - Otherwise connect:
// - normally-closed switches to GND and D32.
// - normally-open switches to 5V and D32.
//
// Normally-closed switches are advised and are the default.
//

//
// The Z_MIN_PROBE_PIN sets the Arduino pin to use. (See your board's pins file.)
// Since the RAMPS Aux4->D32 pin maps directly to the Arduino D32 pin, D32 is the
// default pin for all RAMPS-based boards. Most boards use the X_MAX_PIN by default.
// To use a different pin you can override it here.
//
// WARNING:
// Setting the wrong pin may have unexpected and potentially disastrous consequences.
// Use with caution and do your homework.
//
//#define Z_MIN_PROBE_PIN X_MAX_PIN

//
// Enable Z_MIN_PROBE_ENDSTOP to use _both_ a Z Probe and a Z-min-endstop on the same machine.
// With this option the Z_MIN_PROBE_PIN will only be used for probing, never for homing.
//
//#define Z_MIN_PROBE_ENDSTOP

// Enable Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN to use the Z_MIN_PIN for your Z_MIN_PROBE.
// The Z_MIN_PIN will then be used for both Z-homing and probing.
#define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN //ABL !

// To use a probe you must enable one of the two options above!

// Enable Z Probe Repeatability test to see how accurate your probe is
//#define Z_MIN_PROBE_REPEATABILITY_TEST

/**
* Z probes require clearance when deploying, stowing, and moving between
* probe points to avoid hitting the bed and other hardware.
* Servo-mounted probes require extra space for the arm to rotate.
* Inductive probes need space to keep from triggering early.
*
* Use these settings to specify the distance (mm) to raise the probe (or
* lower the bed). The values set here apply over and above any (negative)
* probe Z Offset set with Z_PROBE_OFFSET_FROM_EXTRUDER, M851, or the LCD.
* Only integer values >= 1 are valid here.
*
* Example: `M851 Z-5` with a CLEARANCE of 4 => 9mm from bed to nozzle.
* But: `M851 Z+1` with a CLEARANCE of 2 => 2mm from bed to nozzle.
*/
#define Z_CLEARANCE_DEPLOY_PROBE 15 // Z Clearance for Deploy/Stow
#define Z_CLEARANCE_BETWEEN_PROBES 5 // Z Clearance between probe points

//
// For M851 give a range for adjusting the Z probe offset
//
#define Z_PROBE_OFFSET_RANGE_MIN -20
#define Z_PROBE_OFFSET_RANGE_MAX 20

// For Inverting Stepper Enable Pins (Active Low) use 0, Non Inverting (Active High) use 1
// :{ 0:'Low', 1:'High' }
#define X_ENABLE_ON 0
#define Y_ENABLE_ON 0
#define Z_ENABLE_ON 0
#define E_ENABLE_ON 0 // For all extruders

// Disables axis stepper immediately when it's not being used.
// WARNING: When motors turn off there is a chance of losing position accuracy!
#define DISABLE_X false
#define DISABLE_Y false
#define DISABLE_Z false
// Warn on display about possibly reduced accuracy
//#define DISABLE_REDUCED_ACCURACY_WARNING

// @section extruder

#define DISABLE_E false // For all extruders
#define DISABLE_INACTIVE_EXTRUDER true //disable only inactive extruders and keep active extruder enabled

// @section machine

// Invert the stepper direction. Change (or reverse the motor connector) if an axis goes the wrong way.
#define INVERT_X_DIR false // true
#define INVERT_Y_DIR true // false
#define INVERT_Z_DIR false // true

// @section extruder

// For direct drive extruder v9 set to true, for geared extruder set to false.
#define INVERT_E0_DIR true // false
#define INVERT_E1_DIR true // false
#define INVERT_E2_DIR true // false
#define INVERT_E3_DIR false

// @section homing

#define Z_HOMING_HEIGHT 4 // //ABL (in mm) Minimal z height before homing (G28) for Z clearance above the bed, clamps, ...
// Be sure you have this distance over your Z_MAX_POS in case.

// ENDSTOP SETTINGS:
// Sets direction of endstops when homing; 1=MAX, -1=MIN
// :[-1, 1]
#define X_HOME_DIR -1
#define Y_HOME_DIR -1
#define Z_HOME_DIR -1

#define min_software_endstops true // If true, axis won't move to coordinates less than HOME_POS.
#define max_software_endstops true // If true, axis won't move to coordinates greater than the defined lengths below.

// @section machine

// Travel limits after homing (units are in mm)
#define X_MIN_POS 0
#define Y_MIN_POS 0
#define Z_MIN_POS 0
#define X_MAX_POS 200 //215
#define Y_MAX_POS 300 //210
#define Z_MAX_POS 170 //180

Edited 2 time(s). Last edit at 01/24/2017 08:29AM by h4nc.

The probe you listed is a normally open type, if you conected it to the Z min enstop pins then you need to set this line to true

#define Z_MIN_ENDSTOP_INVERTING true // ABL // set to true to invert the logic of the endstop.

Thx that worked! Z axis went up because the probe was triggered when the autohome procedure started.