Reset Extruder Position

[sathvik]

Good day, everyone!
With G92 E0, I'm attempting to reset the extruder position. However, it has no effect on the value of my current extruder in DWC.
There are three extruders in my system. And I'd like to modify E2's value (Tool 3).
When I send M114 in DWC, I notice that the value of E (virtual extruder coordinate) is changed rather than E2.
I'm using object model programming with move.extruders[2].position to detect if the extruder has reached its maximum position, and if it has, I want to pausing it, calibrating it, and resetting it to zero so I can repeat the process.

I'd appreciate it if someone could propose a workaround.
This topic has already been discussed but I believe object model programming was not available then: https://forum.duet3d.com/topic/9766/reset-extruder-ignored-in-dwc-and-other-observations

[sathvik]

Using reprap firmware version 3.3

[dc42]

@sathvik as you have observed, G92 only affects the virtual extruder position. The extruder positions reported by DWC are the extrusions since the job started. They depend on many other factors apart from the accumulated extrusion commanded by the slicer, for example mixing ratio, extrusion factor, and nonlinear extrusion.

Please explain what you mean by "calibrating it" (i.e the extruder).

[sathvik]

@dc42 Thank you for your reply
I am currently working on automatic pipetting machine. I want to use extruder as a motor for a pipette. So, when it reaches its max position, I am driving it back and want to set it to zero.

[dc42]

@sathvik have you considered configuring the pipette as an axis instead of an extruder?