Marlin needs to remember z position

Devilclarke

Ok so i need marlin to remember the z position after power off otherwise it sets to 0 and tries to move down to 'clear head' before probing for home. any ideas?

Samuel Pinches

I don't think trying to remember the z-position is a good idea - the idea of endstops is that you never know your reference position when the printer starts. Things can move when the printer is turned off... 

What is the clear head you're talking about? Is this when starting a print? Can't you just use G28 to home printer first?

I assume by "move down", you're referring to the Z-603S with a z-moving bed, rather than an i3 printer with a z-moving nozzle? The proper solution would be to add z-max endstops.

Devilclarke

i am thinking about adding a max z but in the short term wanted to see if we could fix this. it is when calling G28 after xy have homed that it drops the bed ( yes Z-603s)

Samuel Pinches

Even if you modify the firmware to add this feature, the next problem will be that writing the current position to flash memory every time it changes will rapidly wear out the flash memory... 

Devilclarke

no its not every time it can be set to 180 and stay there and when booted it will set z to 180 before home meaning the software end stop will stop homing from pushing it below

Devilclarke

TBH i use the BLTouch for zmin so i may just move the original endstop to z max