Problem with auto-leveling (proximity sensor) Folger Tech--Prusa i3....

Scenario...

Installed proximity sensor--LJ12A3-4-Z-BX for auto leveling, with the necessary voltage divider. Result: just under 4V output, and responds well to my PEI covered aluminum bed.

When I try to home via the home button for ALL axis or via (G28), the sensor keeps attempting to home off the print bed--back/right corner
Side note: Clicking on just the Z axis home button, gives no response.

My failed "SAFE HOMING" code [sigh]:

#define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
                          // When defined, it will:
                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
                          // - Block Z homing only when the probe is outside bed area.

  #ifdef Z_SAFE_HOMING

    #define Z_SAFE_HOMING_X_POINT (X_MAX_LENGTH/2)    // X point for Z homing when homing all axis (G28)
    #define Z_SAFE_HOMING_Y_POINT (Y_MAX_LENGTH/2)    // Y point for Z homing when homing all axis (G28)

Question is... Why is my printer NOT obeying the commands:

"#define Z_SAFE_HOMING_X_POINT (X_MAX_LENGTH/2)"
NOR...
"#define Z_SAFE_HOMING_Y_POINT (Y_MAX_LENGTH/2)"?

Presently using: Repetier-Host.
Build: Folger Tech Prusa i3--obviously; w/ modifications: like aluminum bed, proximity sensor--LJ12A3-4-Z-BX, etc.

My Repetier-Host shows Home where my end-stops dictate--right/back corner.


Here is the pertinent code in the Configuration.h (up-dated version to latest -- edited to match Folger Tech's old) file that I am presently using--no calibration tweaks yet.
Any help in editing it and/or getting to the bottom of this issue I'm having, would be sweet.... AND much appreciated
Maybe someone who owns Folger Tech's prusa i3, that has gone through this scenario?.... Thx
Need any more info? Just ask....

//===========================================================================
//=============================Mechanical Settings===========================
//===========================================================================

// Uncomment the following line to enable CoreXY kinematics
// #define COREXY

// coarse Endstop Settings
#define ENDSTOPPULLUPS // Comment this out (using // at the start of the line) to disable the endstop pullup resistors

#ifndef ENDSTOPPULLUPS
  // fine endstop settings: Individual pullups. will be ignored if ENDSTOPPULLUPS is defined
   #define ENDSTOPPULLUP_XMAX
   #define ENDSTOPPULLUP_YMAX
   #define ENDSTOPPULLUP_ZMAX
   #define ENDSTOPPULLUP_XMIN
   #define ENDSTOPPULLUP_YMIN
  // #define ENDSTOPPULLUP_ZMIN
#endif

#ifdef ENDSTOPPULLUPS
  // #define ENDSTOPPULLUP_XMAX
  // #define ENDSTOPPULLUP_YMAX
  // #define ENDSTOPPULLUP_ZMAX
  #define ENDSTOPPULLUP_XMIN
  #define ENDSTOPPULLUP_YMIN
  //#define ENDSTOPPULLUP_ZMIN
#endif

// The pullups are needed if you directly connect a mechanical endswitch between the signal and ground pins.
const bool X_MIN_ENDSTOP_INVERTING = true; // set to true to invert the logic of the endstop.
const bool Y_MIN_ENDSTOP_INVERTING = true; // set to true to invert the logic of the endstop.
const bool Z_MIN_ENDSTOP_INVERTING = true; // set to true to invert the logic of the endstop.
const bool X_MAX_ENDSTOP_INVERTING = true; // set to true to invert the logic of the endstop.
const bool Y_MAX_ENDSTOP_INVERTING = true; // set to true to invert the logic of the endstop.
const bool Z_MAX_ENDSTOP_INVERTING = true; // set to true to invert the logic of the endstop.
//#define DISABLE_MAX_ENDSTOPS
//#define DISABLE_MIN_ENDSTOPS

// Disable max endstops for compatibility with endstop checking routine
#if defined(COREXY) && !defined(DISABLE_MAX_ENDSTOPS)
  #define DISABLE_MAX_ENDSTOPS
#endif

// For Inverting Stepper Enable Pins (Active Low) use 0, Non Inverting (Active High) use 1
#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 when it's not being used.
#define DISABLE_X false
#define DISABLE_Y false
#define DISABLE_Z false
#define DISABLE_E false // For all extruders
#define DISABLE_INACTIVE_EXTRUDER true //disable only inactive extruders and keep active extruder enabled

#define INVERT_X_DIR true    // for Mendel set to false, for Orca set to true
#define INVERT_Y_DIR false    // for Mendel set to true, for Orca set to false
#define INVERT_Z_DIR true     // for Mendel set to false, for Orca set to true
#define INVERT_E0_DIR false   // for direct drive extruder v9 set to true, for geared extruder set to false
#define INVERT_E1_DIR false    // for direct drive extruder v9 set to true, for geared extruder set to false
#define INVERT_E2_DIR false   // for direct drive extruder v9 set to true, for geared extruder set to false

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

#define min_software_endstops false // 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.

// Travel limits after homing
#define X_MAX_POS 222
#define X_MIN_POS 0
#define Y_MAX_POS 200
#define Y_MIN_POS 0
#define Z_MAX_POS 185
#define Z_MIN_POS 0

#define X_MAX_LENGTH (X_MAX_POS - X_MIN_POS)
#define Y_MAX_LENGTH (Y_MAX_POS - Y_MIN_POS)
#define Z_MAX_LENGTH (Z_MAX_POS - Z_MIN_POS)
//============================= Bed Auto Leveling ===========================

#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line)
#define Z_PROBE_REPEATABILITY_TEST  // If not commented out, Z-Probe Repeatability test will be included if Auto Bed Leveling is Enabled.

#ifdef ENABLE_AUTO_BED_LEVELING

// There are 2 different ways to pick the X and Y locations to probe:

//  - "grid" mode
//    Probe every point in a rectangular grid
//    You must specify the rectangle, and the density of sample points
//    This mode is preferred because there are more measurements.
//    It used to be called ACCURATE_BED_LEVELING but "grid" is more descriptive

//  - "3-point" mode
//    Probe 3 arbitrary points on the bed (that aren't colinear)
//    You must specify the X & Y coordinates of all 3 points

  #define AUTO_BED_LEVELING_GRID
  // with AUTO_BED_LEVELING_GRID, the bed is sampled in a
  // AUTO_BED_LEVELING_GRID_POINTSxAUTO_BED_LEVELING_GRID_POINTS grid
  // and least squares solution is calculated
  // Note: this feature occupies 10'206 byte
  #ifdef AUTO_BED_LEVELING_GRID

    // set the rectangle in which to probe
    #define LEFT_PROBE_BED_POSITION 15
    #define RIGHT_PROBE_BED_POSITION 170
    #define BACK_PROBE_BED_POSITION 180
    #define FRONT_PROBE_BED_POSITION 20

     // set the number of grid points per dimension
     // I wouldn't see a reason to go above 3 (=9 probing points on the bed)
    #define AUTO_BED_LEVELING_GRID_POINTS 3


  #else  // not AUTO_BED_LEVELING_GRID
    // with no grid, just probe 3 arbitrary points.  A simple cross-product
    // is used to esimate the plane of the print bed

      #define ABL_PROBE_PT_1_X 15
      #define ABL_PROBE_PT_1_Y 180
      #define ABL_PROBE_PT_2_X 15
      #define ABL_PROBE_PT_2_Y 20
      #define ABL_PROBE_PT_3_X 170
      #define ABL_PROBE_PT_3_Y 20

  #endif // AUTO_BED_LEVELING_GRID


  // these are the offsets to the probe relative to the extruder tip (Hotend - Probe)
  // X and Y offsets must be integers
  #define X_PROBE_OFFSET_FROM_EXTRUDER -30
  #define Y_PROBE_OFFSET_FROM_EXTRUDER 6
  #define Z_PROBE_OFFSET_FROM_EXTRUDER 0

  #define Z_RAISE_BEFORE_HOMING 4       // (in mm) Raise Z before homing (G28) for Probe Clearance.
                                        // Be sure you have this distance over your Z_MAX_POS in case

  #define XY_TRAVEL_SPEED 8000         // X and Y axis travel speed between probes, in mm/min

  #define Z_RAISE_BEFORE_PROBING 5    //How much the extruder will be raised before traveling to the first probing point.
  #define Z_RAISE_BETWEEN_PROBINGS 5  //How much the extruder will be raised when traveling from between next probing points

  //#define Z_PROBE_SLED // turn on if you have a z-probe mounted on a sled like those designed by Charles Bell
  //#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.

  //If defined, the Probe servo will be turned on only during movement and then turned off to avoid jerk
  //The value is the delay to turn the servo off after powered on - depends on the servo speed; 300ms is good value, but you can try lower it.
  // You MUST HAVE the SERVO_ENDSTOPS defined to use here a value higher than zero otherwise your code will not compile.

//  #define PROBE_SERVO_DEACTIVATION_DELAY 300


//If you have enabled the Bed Auto Leveling and are using the same Z Probe for Z Homing,
//it is highly recommended you let this Z_SAFE_HOMING enabled!!!

  #define Z_SAFE_HOMING   // This feature is meant to avoid Z homing with probe outside the bed area.
                          // When defined, it will:
                          // - Allow Z homing only after X and Y homing AND stepper drivers still enabled
                          // - If stepper drivers timeout, it will need X and Y homing again before Z homing
                          // - Position the probe in a defined XY point before Z Homing when homing all axis (G28)
                          // - Block Z homing only when the probe is outside bed area.

  #ifdef Z_SAFE_HOMING

    #define Z_SAFE_HOMING_X_POINT (X_MAX_LENGTH/2)    // X point for Z homing when homing all axis (G28)
    #define Z_SAFE_HOMING_Y_POINT (Y_MAX_LENGTH/2)    // Y point for Z homing when homing all axis (G28)

  #endif

  #ifdef AUTO_BED_LEVELING_GRID	// Check if Probe_Offset * Grid Points is greater than Probing Range
    #if X_PROBE_OFFSET_FROM_EXTRUDER < 0
      #if (-(X_PROBE_OFFSET_FROM_EXTRUDER * AUTO_BED_LEVELING_GRID_POINTS) >= (RIGHT_PROBE_BED_POSITION - LEFT_PROBE_BED_POSITION))
	     #error "The X axis probing range is not enough to fit all the points defined in AUTO_BED_LEVELING_GRID_POINTS"
	  #endif
	#else
      #if ((X_PROBE_OFFSET_FROM_EXTRUDER * AUTO_BED_LEVELING_GRID_POINTS) >= (RIGHT_PROBE_BED_POSITION - LEFT_PROBE_BED_POSITION))
	     #error "The X axis probing range is not enough to fit all the points defined in AUTO_BED_LEVELING_GRID_POINTS"
	  #endif
	#endif
    #if Y_PROBE_OFFSET_FROM_EXTRUDER < 0
      #if (-(Y_PROBE_OFFSET_FROM_EXTRUDER * AUTO_BED_LEVELING_GRID_POINTS) >= (BACK_PROBE_BED_POSITION - FRONT_PROBE_BED_POSITION))
	     #error "The Y axis probing range is not enough to fit all the points defined in AUTO_BED_LEVELING_GRID_POINTS"
	  #endif
	#else
      #if ((Y_PROBE_OFFSET_FROM_EXTRUDER * AUTO_BED_LEVELING_GRID_POINTS) >= (BACK_PROBE_BED_POSITION - FRONT_PROBE_BED_POSITION))
	     #error "The Y axis probing range is not enough to fit all the points defined in AUTO_BED_LEVELING_GRID_POINTS"
	  #endif
	#endif

	
  #endif
  
#endif // ENABLE_AUTO_BED_LEVELING


// The position of the homing switches
//#define MANUAL_HOME_POSITIONS  // If defined, MANUAL_*_HOME_POS below will be used
//#define BED_CENTER_AT_0_0  // If defined, the center of the bed is at (X=0, Y=0)

//Manual homing switch locations:
// For deltabots this means top and center of the Cartesian print volume.
#define MANUAL_X_HOME_POS 0
#define MANUAL_Y_HOME_POS 0
#define MANUAL_Z_HOME_POS 0
//#define MANUAL_Z_HOME_POS 402 // For delta: Distance between nozzle and print surface after homing.

//// MOVEMENT SETTINGS
#define NUM_AXIS 4 // The axis order in all axis related arrays is X, Y, Z, E
#define HOMING_FEEDRATE {50*60, 50*60, 50, 0}  // set the homing speeds (mm/min)

// default settings

#define DEFAULT_AXIS_STEPS_PER_UNIT   {80,80,4000,90}  // default steps per unit for Ultimaker
#define DEFAULT_MAX_FEEDRATE          {250, 250, 2, 22}    // (mm/sec)
#define DEFAULT_MAX_ACCELERATION      {1000,1000,5,1000}    // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for Skeinforge 40+, for older versions raise them a lot.

#define DEFAULT_ACCELERATION          500    // X, Y, Z and E max acceleration in mm/s^2 for printing moves
#define DEFAULT_RETRACT_ACCELERATION  500   // X, Y, Z and E max acceleration in mm/s^2 for retracts

// Offset of the extruders (uncomment if using more than one and relying on firmware to position when changing).
// The offset has to be X=0, Y=0 for the extruder 0 hotend (default extruder).
// For the other hotends it is their distance from the extruder 0 hotend.
// #define EXTRUDER_OFFSET_X {0.0, 20.00} // (in mm) for each extruder, offset of the hotend on the X axis
// #define EXTRUDER_OFFSET_Y {0.0, 5.00}  // (in mm) for each extruder, offset of the hotend on the Y axis

// The speed change that does not require acceleration (i.e. the software might assume it can be done instantaneously)
#define DEFAULT_XYJERK                20.0    // (mm/sec)
#define DEFAULT_ZJERK                 0.4     // (mm/sec)
#define DEFAULT_EJERK                 5.0    // (mm/sec)

//===========================================================================
//=============================Additional Features===========================
//===========================================================================

..........................

Edited 3 time(s). Last edit at 08/11/2015 09:35AM by 55rebel.

Did you ever solve this? I'm having the same problem too

Edit: Figured it out. Z_SAFE_HOMING doesn't work when X home is at a max endstop. Had to mess around with the configuration and flip the X motor connector, now it works fine. Also, turn on DISABLE_MAX_ENDSTOPS.

Edited 2 time(s). Last edit at 08/29/2015 09:14PM by therippa.

Would you be able to zip up your arduino files you are using? Want to use this sensor with my Folgertech i3 but need to update my arduino, it would be greatly appreciated!

Does anyone that has this working know why the machine will not probe multiple places before printing? I don't understand why nothing I've tried fixes this. I cannot get proper auto_leveling. I finally have it moving properly with Auto_bed leveling enabled. It homes z to 0 then begins to print I have entered the rectangle parameters and change grid points to 3 instead of 2, but I get nothing for these changes from the behavior in the machine. Please help 1 year and counting on trying to fix this issue.

Any help would be greatly appreciated.

If you want it to do a auto level befoer it starts the print, you will need to enter a G29 command in the slicer start g-code (or edit the g-code and insert a G29 )

I have entered G29 into the start code. It doesn't perform a grid probe it lowers the z axis until the probe triggers then starts printing.

Quote
Duteycs
I have entered G29 into the start code. It doesn't perform a grid probe it lowers the z axis until the probe triggers then starts printing.

What firmware is this for ?

Therippa's Marlin firmware for the Folgertech 2020 Prusa i3. I figured out the problem. My endstop settings were preventing the printer from moving during a G29. I finally have this printer usable. Working on Calibration now. Thanks for replying.