Print fan error at end of print - slic3r problem
This post is NOT about a broken cable! It's a software / firmware problem.
I've updated to the latest version of Slic3r PE, and I'm using the latest firmware release also (3.2.1).
Slic3r is creating a problem. It is sending redundant M107's to turn off the print fan at the end of a print. The first one apparently is "baked into" Slic3r; the second command is part of the default "End G-Code" in Printer Settings. And it seems that what happens with these back-to-back commands is that the controller for the fan gets confused and issues a "PRINT FAN ERROR". Unfortunately, this "emergency stop" condition stops the print right there, before the head is retracted away from the finished print, and it also leaves the heat bed control set to the value used during the print (although the nozzle does cool off).
If I eliminate either one of the redundant M107 commands, I don't get the error.
Of course, the firmware in the printer should be able to handle this. We can point a finger at either the firmware developers or Slic3r developers!
G1 E-0.30000 F2100.00000 ; retract
M107 ; disable fan
; Filament-specific end gcode
G4 ; wait
M221 S100
M104 S0 ; turn off temperature
M140 S0 ; turn off heatbed
M107 ; turn off fan
G1 X0 Y200; home X axis
M84 ; disable motors
Re: Print fan error at end of print - slic3r problem
I also had a FAN ERROR yesterday, from out of the blue. Your theory about the redundant M107 commands is interesting, but I'm afraid that it is a bit more complicated than that. I ran the following gcode:
M106 S255
G4 S10
M107 ; disable fan
; Filament-specific end gcode
G4 ; wait
M221 S100
M104 S0 ; turn off temperature
M140 S0 ; turn off heatbed
M107 ; turn off fan
G1 X0 Y200; home X axis
M84 ; disable motors
It did not produce a FAN ERROR, so there must be something else involved. Also, every gcode file I have ever printed on this machine has redundant M107 commands, and this is the first FAN ERROR I have ever encountered.
I am running 3.2.0, so I can't tell if the issue exists in 3.2.1, but if it was as simple as running multiple M107 commands, we would have a lot more complaints about FAN ERROR. We should try to come up with a very small gcode file that triggers the error, so the Prusa team can run it.
Re: Print fan error at end of print - slic3r problem
I must admit, I can't seem to reproduce the problem. BTW, I'm using firmware 3.3.0 now. I'll try to close the issue or report it as non-reproducible on Github.