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So, I'm doing a feedrate/flowrate test from @mhackney 's guide for successful prints and I'm profiling a new filament. I know the GCODE to enter to manually extrude at certain feedrate, etc. However, the machine will never take two commands back to back. I'll enter it once, let it do it's thing, change the temp, and attempt to do it again. But the machine does nothing. This happens both in MatterControl and in Repetier-Host. Has anyone else experienced this before?

My guess is you're probably in absolute extrusion mode instead of relative. So if you tell it to extrude 3mm, it'll do it, and then when you send the same command again, the printer says it's already at 3mm of extrusion, nothing to do. You'd have to say extrude 6mm to get another 3mm. Or go to relative extrusion. G91 for relative position of everything in most firmwares, though reprapfirmware apparently requires M83 for relative extrusion.

Ah ha! Yes, I was doing G1 E5 F60, and from what I've read, the G1 command is absolute movement. Ok. I'll have to look further into this! Thanks a lot!

G1 doesn't specify absolute or relative. That is controlled by the mode the printer is in when the command is passed.

Oh. Really? Ok, I misread. So how is that set in the machine?

M82 sets extruder to absolute. M83 sets it to relative.

Sorry about that, I'm preparing an update with example code that sets the M83 so you are doing relative extrusion moves.

So I can just send M83 first, and then do my tests? I take it that I should probably set it back to absolute before I go back to printing?

mhackney wrote:Sorry about that, I'm preparing an update with example code that sets the M83 so you are doing relative extrusion moves.

Are you going to mention that those tasks can be most easily achieved by manually inputting the GCODE into the host? I think it would be good to mention since that's the simplest way to accomplish it. If you already stated that, I apologize as I did not notice.

That should work.

Actually, you can print in either mode, provided you (or the start gcode generated by your slicer) set(s) the appropriate mode for the setting you're using in the slicer.