JohnSL FSR board and z probe setup
This question regarding z probing using JohnSL FSR board. That board has 3 FSR connection. My printer will have dual extruder with its own x and z axes. For setting bed mesh levelling, Do I need two of JohnSL board or 1 is sufficient?
I'd like to use only 1 FSR board and use that same FSR to probe both head independently. Is this doable? If so then I think this would automatically took care of the offset between the two hotends in the event of changing nozzles
On a standard IDEX machine with independent X carriages but a common Z axis, I think you could run G29 bed probing separately for each head, storing the resulting height maps using different filenames. Then in the tpost#.g tool change files, load the height map for the incoming tool.
If you have a separate Z axis for each head, one option might be to use the FSRs to Z home each head independently, switching the Z axis to the appropriate motor driver using M584. After homing both, use M584 to assign both drivers to Z.
Either way, only one FSR interface board needed.
thank you 42 I do have separate Z axis and got the duex5 as well
I'm not sure what you mean by "use M584 to assign both drivers to Z."
I was about to use
M584 X0 Y1 Z2 U3 V4 E5:6 ; U for the other x axis and V for the other z axis and basically the two extruder motor will connect to Duex5
The current firmware doesn't support remapping the Z axis in the way that it supports remapping X and Y, so you can't use V as a substitute Z axis. That's why you will need to use M584 to change the Z driver mapping if you want to perform G29 mesh bed probing separately for each head. If you are happy with both Z motors moving together most of the time, then Z2:4 can be the normal mapping in M584 and you can change it to Z2 or Z4 just when you want to probe the bed.
Will that be implemented in future firmware? I think it would continue to build upon the idea of U map to X and V map to Z