Postby Jetguy » Fri Mar 17, 2017 6:39 pm
The power fail resume function only works if the following conditions are met:
#1 battery is fully charged or near fully charged at the time of power failure. I don't know what the minimum required is (that changed with raisepack versions on the pcduino over time), but let's say 95% or better
#2 The gcode file being print contains the proper M1001 and M1002 command lines at the end of the starting gcode sequence and beginning of the end gcode sequence. By default, Ideamaker software has these in the slicer settings. Other 3rd party slicers need them added.
When the power fails mid print after you have gotten past the starting gcode sequence (homing, preheat, and extrusion prime) then during the print, the power is lost and the motion board and all 24V systems lose power. At that point, the pcDuino front panel LCD streaming the gcode to the motion board sees both the power loss event (because it's powered via 24V) and sees the motion board drop off and not send the last line completed) then on battery power, the pcduino writes a save point of the last gcode completed, says this on the LCD, and then shuts down the linux operating system.
When you power on the next time after such an event where ALL conditions were met AND the system said it saved a valid dump file (basically did not say Dump file NOT saved), then upon startup the first screen asks if you want to resume that saved dump file job. If you resume, it rehomes XY only and not z, and then heats up, extrudes, and then starts where it left off.
Again, assumptions that can go wrong here:
Recovery works only in a certain state of battery, in a certain sequence, only if everything is correct.
It depends on the Z axis friction that the Z stage and build plate DO NOT MOVE in the off state after the print. Since there is something on the build plate, there is no way to rehome Z axis safely. Again, this entire system not only depends on the save function, but the assumption the build plate does not move during the off state.
Finally, it assumes that as the bed cools down without heat power, that the part remains firmly stuck. If the part curls up, warps, or other problems like breaking free, you cannot effectively recover that print.
