Upper limit switch in addition to the bltouch for origin

[siskusan]

Hello, Could someone tell me how you can program a Z limit switch so that when you step on it, it reverses the movement of the axis and continues the search for the origin with the BLtouch when homing is requested from the printer, in case of being close to the physical limit of height?
Thanks

[rjenkinsgb]

Just look at a typical axis homing sequence - a fast move to the switch, back off, then a slow move to the switch.

If you do the fast move, then back off, move X/Y to the correct position for the probe reference and do G30, that should work, I believe.
eg. something like this?

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v3.3.2 on Mon Sep 13 2021 22:19:30 GMT+0100 (British Summer Time)
G91               ; relative positioning
G1 H2 Z5 F6000    ; lift Z relative to current position
G1 H1 Z-305 F1800 ; move Z down until the endstop is triggered <<< Adjust maximum height
G92 Z0            ; set Z position to axis minimum (you may want to adjust this)

; Uncomment the following lines to lift Z after probing
G91              ; relative positioning
G1 Z5 F100       ; lift Z relative to current position
G90              ; absolute positioning

; Move X & Y to probe position
G0 X100 Z100 ; <<<<<<<<<<<<<<<<<<Set appropriate position

; Probe for precise zero
G30

I just have the normal endstop/limit switch Z reference, then do a bed level and Z reference etc. in the start code section of the slicer start gcode.

[siskusan]

Thanks is not exactly what I need but it has given me an idea, I don't really want to go to the limit every time I originate, I just need to be able to move the Z axis towards the table in the case of a stop near the upper physical limit, When executing Home Z it rises 5mm and ends up crashing, what I am going to do is create a macro according to your proposal to be able to move the Z towards the table a distance of 10 mm despite not having the origin and then do homing.

Macro: Move Z without origins
G91; relative positioning
G1 H2 Z5 F6000; lift Z relative to current position

I really appreciate your help and interest
Greetings