Marlin responding differently to pronterface commands vs SD card gcode Been testing my ATMega256 marlin laser engraver with pronterface, and all the motion commands work, and things like G0 S200 X60 Y60 will move the head and also activate the laser for the entire motion. Great. I put the same in a gcode test file to run from an sd card: G1 S200 X100 G0 S200 X100 Y60.333 G1 S200 X0 G0 S200 X0 Y60.667 G1 S200 X100 a simple back and forth scanning pattern ... and the laser blinks every time the command changes - that is, when it changes direction, I see the laser flash briefly - but for the rest of the time the laser is off. Why might this be? Not sure if this is related, but I can also manually turn the laser on with M4, but then any motion immedialtey turns it off again. Appreciate any advice or things to try! Can also provide more detail and context if needed, apologies if this was not enough. https://reprap.org/forum/read.php?415,890410,890410#msg-890410 Tue, 06 Oct 2026 05:22:19 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?415,890410,890432#msg-890432 Re: Marlin responding differently to pronterface commands vs SD card gcode https://reprap.org/forum/read.php?415,890410,890432#msg-890432 VDX Firmware - Marlin Fri, 02 Sep 2022 06:06:52 -0400 https://reprap.org/forum/read.php?415,890410,890428#msg-890428 Re: Marlin responding differently to pronterface commands vs SD card gcode https://reprap.org/forum/read.php?415,890410,890428#msg-890428 maccadacca Firmware - Marlin Thu, 01 Sep 2022 23:30:00 -0400 https://reprap.org/forum/read.php?415,890410,890422#msg-890422 Re: Marlin responding differently to pronterface commands vs SD card gcode https://reprap.org/forum/read.php?415,890410,890422#msg-890422 rq3 Firmware - Marlin Thu, 01 Sep 2022 13:40:32 -0400 https://reprap.org/forum/read.php?415,890410,890413#msg-890413 Re: Marlin responding differently to pronterface commands vs SD card gcode https://reprap.org/forum/read.php?415,890410,890413#msg-890413 VDX Firmware - Marlin Thu, 01 Sep 2022 05:01:46 -0400 https://reprap.org/forum/read.php?415,890410,890410#msg-890410 Marlin responding differently to pronterface commands vs SD card gcode https://reprap.org/forum/read.php?415,890410,890410#msg-890410 G1 S200 X100
G0 S200 X100 Y60.333
G1 S200 X0
G0 S200 X0 Y60.667
G1 S200 X100

a simple back and forth scanning pattern ... and the laser blinks every time the command changes - that is, when it changes direction, I see the laser flash briefly - but for the rest of the time the laser is off. Why might this be?

Not sure if this is related, but I can also manually turn the laser on with M4, but then any motion immedialtey turns it off again.

Appreciate any advice or things to try! Can also provide more detail and context if needed, apologies if this was not enough.]]> maccadacca Firmware - Marlin Thu, 01 Sep 2022 00:04:09 -0400