Z Offset problem

Hello!
I have "Electron 3D - Sixth Generation Prusa i3" and I use Cura and Pronterface on Mac.
Almost everything is perfect except one problem. All my prints become 0.8 mm lower in Z axis. No matter if it is 10 or 50 mm high object.
When I move the print head to home position LCD screen show that Z is at 0.8. Through printers LCD at Z Offset settings I can get it down to 0.5mm, but when in Pronterface I move to Home position its again goes back to 0.8. How to get rid of it? Is it somewhere in firmware? When I adjust Pronterface Z Offset settings (Settings/Options/Build dimensions/Z offset) it makes no sense. Probably I do something wrong...
It is only first spool of filament for me, so I am absolute beginner and ask for your help!
Martins

There is a command somewhere that will reset the Z height.

Hello!
So, nobody can help me...?

I'm a newbie too, so take this with a pinch of salt, but... If the LCD is showing the Z0.8 that suggests the motors have not skipped steps (because the controller has counted the Z0.8).

Where is the endstop for the Z axis ? For my printer I have the endstop mounted just above one of the Z motors so the nozzle just touches the printbed when it homes, and then Slic3r is set with a Z offset of -0.5 so that the Z zero position is just above the home position. I think you can also set the offset using the G92 gcode (so I use 'G92 Z-0.5').

Try checking the end stop position, and also make sure you've calibrated the Z axis correctly (so a move of 100mm actually moves 100mm).

Paul.

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www.paulhurley.co.uk