@dsela said in Trouble setting up a second extruder:
question, if I have two extruders and I only want to set one, what is the correct syntax?
There's this note on the M584 Gcode dictionary entry:
Every driver that is assigned must have its current set using M906. Not setting a current will default a low current (approx 1/32 of the driver max current), however M906 will report 0 until a current is assigned. Disable the driver explicitly if you do not want any current sent to a driver that is assigned.
Though this applies mainly to internal drivers (and explains why your second extruder wasn't working), it means that external drivers have the current set to 0 in the firmware. Realistically, this doesn't matter, as that setting is not sent to the external driver anyway.
So you can set the external driver current to any value you want; it doesn't matter, as the setting isn't applied to external drivers. But you do need to set the current of the second driver, and to index that, you need to set the current of the first driver (despite it being external) to something, so it knows that the second value relates to the second driver. You can use M906 E0:1000, or set one M906 value to apply to all extruders, eg M906 E1000. While the firmware will report the current setting for each extruder drive, the current for the external driver is irrelevant.
Ian