Hello I'm having a problem with the sequence order of events. I am under the impression that g-code (or the machine) will wait for each command to complete before moving on to the next command. But I'm not seeing this.
I have a plotter machine that controls a pen. The machine has an X & Y axis. The Pen Up/Down command is controlled by a code M280P0S30/M280P0S0
The pen is going down too early. I can see 2 possible reasons for this:
- Perhaps there's some problem here with my code or understanding of what these codes do
G28 X Y ; Auto-home
G90 ; ABS
G21 ; MM
G1 F3000 ; Speed
M280P0S30 ; Pen up
;;; Problem occurs here: Pen goes down
G1 X50 Y50 ; Move command
M280P0S0 ; Pen down
G4 P50 ; Pause
G1 X50 Y55 ; Move command
G1...snip.... more move commands
Can anyone tell me if there are any mistakes here?
- Perhaps the M280 codes do not wait for the G1 codes to complete?
- Perhaps the G4 code is throwing things off?
- Perhaps I need a faster/slower speed?
- I am wondering if the machine buffers and blocks individually based on the type of codes. (A G1 command would block another G1 command but not a M280 command.)
I'm sending the commands over a serial connection. There are too many commands to send all at once so I introduced a pause between the commands. Is it possible that the machine blocks and buffers per-servo? In pseudo code that looks like:
Wait 1 second
Send g-code command: G28 X Y ; Auto-home
Wait 1 second
Send g-code command:G90 ; ABS
Wait 1 second
Send g-code command:G21 ; MM
Wait 1 second
Send g-code command:G1 F3000 ; Speed
Wait 1 second
Send g-code command:M280P0S30 ; Pen up
Wait 1 second
(Problem occurs here: Pen goes down)
Send g-code command:G1 X50 Y50 ; Move command
Wait 1 second
Send g-code command:M280P0S0 ; Pen down
Wait 1 second
Send g-code command:G4 P50 ; Pause
Wait 1 second
Send g-code command:G1 X50 Y55 ; Move command
Is it possible that the machine will allow an M280 code to run before a G1 code if the machine is currently busy with an existing G1 code?
