Perpetual Pending for Extruder Temperature to be reached

Recently this problem appeared out of nowhere, and I think it's happening in Slic3r, because when I load old gcode files into Repetier, the problem disappears.

The problem is: A few days ago, I went to print something, and after the bed and hotend were done heating, the printer just sat there motionless and wouldn't continue through the code: there was no movement.

The eventual solution was to delete the "wait for extruder temp to be reached" line out of the start of the gcode, and for that to work I've needed to wait until the extruder is hot before I start the program, which means I can't just press play on a cold printer and walk away.


My gcodes that are more than a week old have no problems, while the new ones do, despite identical lines.... It makes no sense. Maybe it's a problem with Repetier, but, as I said, old gcode files don't get hung up.

I suppose you'd like to see my gcode.

This first one is the code that first gave me the problem of not starting:

; generated by Slic3r 1.1.7 on 2015-03-23 at 17:19:21

; perimeters extrusion width = 0.50mm
; infill extrusion width = 0.50mm
; solid infill extrusion width = 0.50mm
; top infill extrusion width = 0.50mm

G21 ; set units to millimeters
M190 S70 ; wait for bed temperature to be reached
M104 S220 ; set temperature
G28 ; home all axes
G1 Z0.200 F100 ; lift nozzle
M109 S220 ; wait for temperature to be reached
G90 ; use absolute coordinates
G92 E0
M82 ; use absolute distances for extrusion
G1 F2400.000 E-3.00000
G92 E0
G1 Z0.350 F9000.000
G1 X53.161 Y40.413 F9000.000
G1 E3.00000 F2400.000
G1 X54.235 Y39.012 E3.23760 F1200.000
G1 X55.377 Y37.664 E3.47530
G1 X56.583 Y36.374 E3.71299
G1 X57.851 Y35.145 E3.95065
G1 X59.178 Y33.980 E4.18828
G1 X60.560 Y32.881 E4.42598
G1 X62.194 Y31.719 E4.69579

(Problem solved by deleting "M109 S220 ; wait for temperature to be reached")

This second one is code from two days earlier, code that has no problems:

; generated by Slic3r 1.1.7 on 2015-03-21 at 07:38:48

; perimeters extrusion width = 0.50mm
; infill extrusion width = 0.50mm
; solid infill extrusion width = 0.50mm
; top infill extrusion width = 0.50mm

G21 ; set units to millimeters
M190 S70 ; wait for bed temperature to be reached
M104 S220 ; set temperature
G28 ; home all axes
G1 Z0.200 F100 ; lift nozzle
M109 S220 ; wait for temperature to be reached
G90 ; use absolute coordinates
G92 E0
M82 ; use absolute distances for extrusion
G1 F1800.000 E-3.00000
G92 E0
G1 Z0.350 F9000.000
G1 X74.267 Y83.938 F9000.000
G1 E3.00000 F1800.000
G1 X75.702 Y82.844 E3.24283 F1200.000
G1 X77.210 Y81.930 E3.48009
G1 X78.516 Y81.292 E3.67576
G1 X82.852 Y79.411 E4.31184
G1 X83.597 Y79.135 E4.41879
G1 X85.128 Y78.641 E4.63534
G1 X86.024 Y78.403 E4.76007

Edited 1 time(s). Last edit at 03/26/2015 02:06PM by kre8.

As you say, it makes no sense because the codes up to the "M109" command are identical. I suspect therefore that there is another variable present - some difference in the printer's state when you ran the new code to when you ran the older code. There is another possibility - the printer controller almost certainly buffers commands, and so there may be a command some way past the start code that causes the problem when it is buffered (though it is difficult to see how). If you cannot think of any differences in the printer's state, you could try editing the problem G code by removing everything after the first move and see whether that freezes at the M109. If not, add more and more of the original file until you hit the problem.

One other possibility I can think of - there is a rogue character (byte) in the file that does not show up in a text editor but is causing the issue. The rogue byte could be deleted when you delete the M109 line - either because it is in that line or because your text editor filters out all non-ASCII characters when it saves an edited file. You could therefore try looking at the file with a HEX editor for any strange characters. (e.g. the byte 0x04 won't necessarily show in a text editor but could be interpreted as "end of file" by the printer controller).

Dave

Are you by chance SD printing? If you have the checkboxes to include start and finish gcode selected when uploading your file to the SD card that may be messing with your results.