Having issues using MATLAB to generate gcode to control stepper motor

[Jooseppi Luna]

Hi everyone! I'm having some strange issues using MATLAB to send gcode to an Arduino to control a stepper motor. This is my code. I have comments in there to explain it.


%Open serial port to send commands to the Arduino
s = serial('COM12');
set(s,'BaudRate',115200);
fopen(s);

%Wait for grbl to initialize
pause(2)

%Output GCode.
for i = 1:20
fprintf(s,'G01 X%d F1000\n',40 * i);
fprintf(s,'G4 P2\n');
pause(5); %This makes things work?
end

fclose(s);
delete(s);
clear s;


The main issue with the code is that, if I loop without the pause(5) in the loop, the motor will loop at most 7 times before stopping. I have put a print statement that prints the value of i into the loop, and it does print the numbers 1-20, so the loop is not an issue. The weird thing is that, if I throw in a pause() command, the loop will run for longer depending how long a time I specify for the pause. Pause(5) is enough for me to run all twenty runs.

Any idea what is going on here?

[James Riley]

Your Baud rate is pretty high. Could you settle for a rate that more closely matches your driver? You might find that your PC has a faster processor than your driver, therefore completing the loops in record time while the driver got fed too quickly. First time posting, sorry if you've considered this.