I brought this thread back to life as my question is related...and keeping the answers together seems like a good idea.
My printer is.a delta...
I have dual extruders, both offset along the Y axis. I leveled the printer quite well with extruder one before I enabled extruder 2, although it was always installed and skims just above the prints made by extruder 1 as desired. When I went to try using extruder 2 I first just put in the offset from extruder 1 in the firmware......this worked okay...but I wanted to maximize my print area and wanted to split the offsets between the extruders so one was positive the other negative. So if the distance between them is 2000 steps then Ext1 would be -1000 and Ext2 would be 1000. This would center the effector over then bed....
But something odd happens when I try this....the nozzles now ride several mm above the bed and are not completely offset from each other correctly...this seems really wrong compared to more normal operation with just the second extruder offset by a positive number.
Maybe this has to do with how I calibrated the bed but I don't see how. While I did get everything flat knowing that EXT1 was offset from center the whole effector plate seems to move flat so I don't think this is some effector tilt issue....
Any Ideas? Maybe negative extruder position offsets are just not allowed?
Thanks