Z_RAISE_BEFORE_HOMING / G28 / G28XY

[woodsmoke]

Core XY printer, Marlin development downloaded 02/03/15. Arduino 1.05

define Z_RAISE_BEFORE_HOMING 4

Start Printer, G28 (or) G28XY. Neither command raises the Z before homing.

See #1549 for Marlin config.

[thinkyhead]

Try adding these lines immediately after line 1638 (#if defined (Z_RAISE_BEFORE_HOMING) && (Z_RAISE_BEFORE_HOMING > 0)) and see if it makes any difference....

current_position[Z_AXIS] = 0;
plan_set_position(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS]);

[thinkyhead]

Hmm, well never mind! That change won't matter if you have Z_SAFE_HOMING enabled.

[thinkyhead]

So... You should print out some messages to the serial out at the point where it might be failing, and see what's going on. Insert some statements like the following between lines 1648-1660 and then try G28 to see how it behaves....

  SERIAL_ECHO_START;
  SERIAL_ECHOPAIR("z dest:", destination[Z_AXIS]);
  SERIAL_ECHOLN("");

[thinkyhead]

From what I can see, this routine has never been programmed to raise the Z before homing with G28 XY. Only homing commands that include Z (G28, G28 Z, G28 XZ, G28 YZ, and G28 XYZ) are programmed to invoke Z_RAISE_BEFORE_HOMING, and only G28 and G28 XYZ are programmed to invoke it without first having homed X and Y to a known position (setting the axis_known_position flags).

[woodsmoke]

I'll begin my adventures in coding forthwith

[boelle]

is this related to #1553 ?

[woodsmoke]

It works now

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