@dc42
As you can see half way through the code, we did use G92 E0. But apparently it only resets 'E'. But I want it to reset E0 or E1 depending on the tool I have chosen. How do i do that?

@T3P3Tony
I'm sorry, you suggest M92 E0. But M92 sets axis steps/mm

So we have we a system with 5 axes: XYZ and two separate extruder axes U and V. These are btw not filament extruders but piston extruders that have a real absolute position.

What we would like to do is to be able to control them completely separately. I know we can do this by using U and V, but we have reasons to try to do this with a tool change and setting E for extrusion. In addition we would like to be able to issue a G92 E0 for each extruder separately when needed.

So now we run into a problem. I’ll explain with some manually entered Gcode and M114 commands to show the position of each extruder axis.

We start with a fully initialized and homed machine:

M114 --> X:0.000 Y:0.000 Z:50.000 U:0.000 V:0.000 E:0.000 E0:-0.0 E1:-0.0

M82; Make sure we extrude in absolute mode

T0; choose first tool
G1 E12 F500; extrude 12 mm on the first tool
M114 --> X:0.000 Y:0.000 Z:50.000 U:0.000 V:0.000 E:12.000 E0:12.0 E1:-0.0

So far it looks ok-ish, i.e.: E0 is at 12 mm as expected, E1 is still at 0; it is unclear to me how to interpret the value of ‘E’ but it is also set to 12.

T1; switch to second tool
G1 E28 F500; extrude 28 mm on the second tool
M114 --> X:0.000 Y:0.000 Z:50.000 U:0.000 V:0.000 E:28.000 E0:12.0 E1:16.0

Now it gets weird. I would have expected E1 to be at 28, but it is only at 16. And we have indeed verified that this tool has only moved 16 and not 28. The ‘E’ value is 28, whatever that means.

T0; switch back to the first tool
G92 E0; set its position to 0
M114 --> X:0.000 Y:0.000 Z:50.000 U:0.000 V:0.000 E:0.000 E0:12.0 E1:16.0

Now it gets even more confusing. I was hoping to set the position of the left extruder to 0, but only the value of ‘E’ has been set to 0, while the E0 and E1 remain at their former values.

T1; switch to the second tool
G92 E0; set its position to 0
M114 --> X:0.000 Y:0.000 Z:50.000 U:0.000 V:0.000 E:0.000 E0:12.0 E1:16.0

Same problem as with T0.

So the big question is: how do I control both extruders separately in absolute mode whilst using the tool change commands?

Thanks for any insights into this behaviour.

@chrishamm configtool.json
here ya go

@droftarts Thanks Ian for your quick response. I understand, and I kinda figured that out in the mean time. But because of the strange choices in the config tool, I thought I was doing something wrong. I'm gonna try it...

Hi. I'd like to add an analog sensor to my configuration. As there are no generic analog sensors defined, I've chosen to add a temperature sensor and define the type as 'linear analog' as this comes closest to what I need. Here, I also have to choose an input port obviously. I understand that the only analog input ports on the DUET 3-6HC board are the z-probe inputs io0 .. io4 and the thermistor inputs temp0 .. temp3. However, for the analog input port, the config tool gives me the options: out4, out4.tach or out5.tach. That sounds very wrong to me; I need an input port, not an output port, so I was expecting to be able to choose from temp0 .. temp3. What am I missing here?

In addition, if I choose e.g. out5, the input field in the tool does not get a green outline. Furthermore, the relevant section in the configtool.json file still reads as if no port has been assigned:
"analog": [{
"beta": null,
"c": null,
"lastReading": null,
"name": "position sensor",
"port": null,
"r25": null,
"rRef": null,
"state": "ok",
"type": "linearanalog"
}