Print Rescue

Over the last couple of years I've lost a few prints because of power failures.  I know, I should have a UPS on each printer but I don't.  In fact, a couple of the power failures have lasted long enough to kill my one UPS battery during a print.

I used to use Octoprint when I had one printer.  I now have three.  Running multiple instances of Octoprint was not an option.  I finally decided to try Repetier server.  I love it!  I had a couple of times the power went out and the print stopped and I noticed the "Rescue" option, but I didn't know how to get the z height correct and have no z max sensor.  Last night my power went out toward the end of an 8 hour print.  I was furious.  Instead of writing it off I decided to see what it would take to rescue my print.  It already homes x and y on power failure recovery so all I had to do was either set the correct z height or home z.  Luckily the print was far enough back from the gantry I was able to home on the front left corner and, to be safe, I wanted to raise the z height to the last known location so I just copied and pasted the gcode to the console - G1 Z40.150 F180 (from the logs).  I hit "Rescue" and it went directly over to the correct location and started printing. 

I am even more impressed with Repetier than I was before, and I was already very impressed! 

Now to figure out how to recover my core xy that homes in the middle of the bed.  Is there a way to tell the printer that the current z height is xxx?


  • Found it.  In theory G92 Z40.150 should have told the printer that it was currently at Z40.150 without homing.  That is if the printer was not in the middle of a z hop when the power went out.
  • If your printer allow moving z without homing there is nothing to do. Server should send G92 Zlastz on it's own as it assumes you are on z height of the line from where you continue.

    z hop is in deed the weak point here. Since moves are buffered and due to power loss last lines may also not be logged there is no way for the server to detect if you are in z hop or not. So all you can do is move manually over the print to judge your self if you are in z hop or not and select a line after or before z hop from where server thinks it was.
  • Yea I figured out the G92 part.  For z hop I would need to look closer at the gcode since Simplify 3D controls that and not firmware.  I just need to make sure there is a E command after the last Z command.  If so it is on a printing layer and not a travel layer.  The hardest part is remembering to do that lol.

    But I am super excited to not lose more prints from power loss.  Thanks for the great software!
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