Fan assignment clarification under RRF3

jens55

I let the smoke escape from one of my mosfets that control the fans (thought the fuse would cover stupidity but sadly it didn't)
The fan in question is fan 1 and I figure I would just re-route everything to fan 2 for now.

My current fan assignments in config.g are:

M950 F1 C"fan1" ; create fan 1 on pin fan1
M106 P1 S1 H1:2 T45

I thought that I could just change "fan1" to "fan2" but obviously my understanding of the RRF3 configuration lines is incorrect.
My thought was that the M950 line assigns the "fan1" connector to fan 1 which is why I thought I could get away with changing only the fan1 connector to the fan2 connector (ie M950 F1 C"fan2")
My interpretation of the next line is that now that the fan2 connector is assigned to be the second (F1) fan, I can configure that fan (P1) to run full speed (S1) when heater 1 or heater 2 (H1:2) exceed 45 degrees (T45) but that doesn't work.
To make it go I had to change the second line to use P2 which doesn't make sense. I don't recall exactly what all I changed
I have been reading the documentation but I am obviously mis-interpreting things and unless I can get it straight in my head, it will surely bite me in the behind at a future time.

Thanks in advance for any clarification.

dc42

If you are running RRF 3.0 and not one of the 3.01 beta versions, then most likely you still have Fan 2 assigned to the fan2 output, so that output isn't free. Try this:

M950 F2 C"nil"
M950 F1 C"fan2"

In 3.01 we've removed the default fan assignments, so the second command should work by itself.

jens55

Thanks, that fixes it and things make sense again. I was under the impression that RRF3 had no default assignments so it never occurred to me that there might be a conflict.

dc42

@jens55 said in Fan assignment clarification under RRF3:

Thanks, that fixes it and things make sense again. I was under the impression that RRF3 had no default assignments so it never occurred to me that there might be a conflict.

RRF3 on Duet 3 has no default assignments. RRF 3.0 on Duet 2 does; but after seeing the problems it can cause, we decided to remove the default assignments in the 3.01 beta releases.

jens55

Ahhh, good call !