Z-axis motors move up when auto-homing - I3 Pro B w/GT2560

[mespilus]

I've just finished my build with the I3 Pro B acrylic printer with a GT2560 controller board. When I auto-home the stepper motors (either from within Repetier or from the LCD display), the X and Y steppers go the correct direction, but the Z axis stepper motor moves UP (away from the heater bed), when it should be moving DOWN towards the heater bed and the endstop. It moves up about 5mm and then stops. Once it stops, I cannot manually move the Z-axis steppers back down again. Any ideas?

[Sherry]

I've just finished my build with the I3 Pro B acrylic printer with a GT2560 controller board. When I auto-home the stepper motors (either from within Repetier or from the LCD display), the X and Y steppers go the correct direction, but the Z axis stepper motor moves UP (away from the heater bed), when it should be moving DOWN towards the heater bed and the endstop. It moves up about 5mm and then stops. Once it stops, I cannot manually move the Z-axis steppers back down again. Any ideas?

hi,please reburn the firmware,and tell me the result.

[mespilus]

Is the firmware available for download anywhere? I tried the one that was posted in the Extruder forum, but it does not compile. It says that "Liquidcrystal does not name a type". It seems that LiquidCrystal.h is missing from the download.

[Sherry]

Is the firmware available for download anywhere? I tried the one that was posted in the Extruder forum, but it does not compile. It says that "Liquidcrystal does not name a type". It seems that LiquidCrystal.h is missing from the download.

The firmware is in the atttachment.

[mespilus]

Thanks! I managed to get the firmware to compile and upload this time. However, after restarting the printer, it is still doing the same behaviour on the Z-axis. It appears this firmware isn't right either. What can I do now?

[mespilus]

Ok, I have part of the problem solved. I changed the following line in the firmware to true (previously was false) as directed in some of the other posts on here.

#define INVERT_Z_DIR true // for Mendel set to false, for Orca set to true

Now the auto-homing is going in the correct direction, but the z-axis will only move about 2 - 5 mm before it stops. It appears to set the stopping location as the zero coordinate for the z-axis. If I auto-home again, it moves another 2 - 5 mm. I repeated this about 30 times before the motor finally hit the z min endstop correctly. Any idea why the z-axis is only moving 2 - 5 mm at a time when auto-homing?

[Sherry]

hi,please check whether the z-endstop wire is well connected. z-endstop wire should connect to z-min slot.

[mespilus]

That got it! One of the connectors wasn't crimped correctly. I tightened it up and attached it back to the z-axis end stop and it is now auto-homing correctly.

Thanks so much!