Upward homing Z axis

I am having a very hard time getting my print to home upwards then when the print starts go down to bed level. I have tried many different combinations in Marlin including replicating the Configuration.h nophead provided on Github. When I manually jog it down to bed level and send the M114 command it says Z:0, but when I home to the top Z is also 0. Any ideas?

EDIT: Before I print and home Z with pronter face it says that it is at 209.10 which is correct. As soon as I start the print and send m114 it says that the top is at 0. Is there a setting in slic3r that I am missing?

Current settings:
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.

// Travel limits after homing
#define X_MAX_POS 205
#define X_MIN_POS 0
#define Y_MAX_POS 205
#define Y_MIN_POS 0
#define Z_MAX_POS 211
#define Z_MIN_POS 0
// 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 {3000, 3000, 200, 0}  // set the homing speeds (mm/min)

// default settings

#define DEFAULT_AXIS_STEPS_PER_UNIT   {4.968,4.968,159.00,760*1.1}  // default steps per unit for Ultimaker
#define DEFAULT_MAX_FEEDRATE          {3000, 3000, 200, 25}    // (mm/sec)
#define DEFAULT_MAX_ACCELERATION      {3000,3000,100,10000}    // 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          3000    // X, Y, Z and E max acceleration in mm/s^2 for printing moves
#define DEFAULT_RETRACT_ACCELERATION  3000   // 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                15.0    // (mm/sec)
#define DEFAULT_ZJERK                 0.4     // (mm/sec)
#define DEFAULT_EJERK                 5.0    // (mm/sec) 
#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)

// 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 {3000, 3000, 200, 0}  // set the homing speeds (mm/min)

// default settings

#define DEFAULT_AXIS_STEPS_PER_UNIT   {4.968,4.968,159.00,760*1.1}  // default steps per unit for Ultimaker
#define DEFAULT_MAX_FEEDRATE          {3000, 3000, 200, 25}    // (mm/sec)
#define DEFAULT_MAX_ACCELERATION      {3000,3000,100,10000}    // 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.

Edited 2 time(s). Last edit at 06/06/2014 09:29PM by jakobnator.

Where is your Z_HOME_POS ?

That should be 209.1....

Is that all in the file too because it's somewhat duplicated.....

If you are trying to emulate nophead's settings for Marlin in a later version, which you appear to be doing, then you need to do two things:

1. Uncomment #define MANUAL_HOME_POSITIONS
2. Set #define MANUAL_Z_HOME_POS to your Z height value

Of course you will also need to set MANUAL_X_HOME_POS and MANUAL_Y_HOME_POS to correct values.

Regards,
Neil Darlow

EDIT: Added hint about MANUAL_X_HOME_POS and MANUAL_Y_HOME_POS.

Edited 2 time(s). Last edit at 06/08/2014 06:05AM by neildarlow.

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

Sorry for bringing back an old thread but I am still having the same issue. I have done as you said with the MANUAL_HOME_POSITIONS and setting the Z height. Still no dice, after homing the Z axis and sending the m114 command it says that it is at the top of the build volume (557.4). However, as soon as the print starts it stays at the top and prints, once I stop the print it says the top is at 0. Then once I home it again it says its back at 557.4. Very strange.......

557.4? I thought you said home was 209.1.

What does the start of your gcode look like? Maybe it changes Z.

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[www.hydraraptor.blogspot.com]

Yea I am not so sure why it is such a big number but, I can try recalibrating my steps per mm later. Slic3r gcode starts with:

G28 ; home all axes
G1 Z5 F5000 ; lift nozzle

EDIT: I would also like to point out that when the print starts it makes this very loud "charging" sound, it kind of sounds like a capacitor charging but a lower pitch. I can only assume that this is it attempting to send G1 Z0 command but it fails to actually move. Another strange thing is if I home the z axis in pronterface, then try to send G1 Z0 it won't work unless I jog the z a little beforehand. Any ideas?

EDIT2: I fixed it, I didn't realize that the max feedrate was mm/sec instead of mm/min which can be seen in homing feedrate and pronterface.

Edited 3 time(s). Last edit at 07/05/2014 12:21PM by jakobnator.