What voltage have you set the stepper driver to?
Frankly I'd experiment with a 3.3V drive to the control pins PUL and DIR, and get rid of the MOSFETs and 12V PSU. Since the inputs are just optoisolators I'd suggest that 3.3V would be sufficient to activate them.
I'd set the driver voltage to 5V, connect PUL+ and DIR+ to two GPIO pins on the Pi, and connect PUL- and DIR- to Pi GND. In fact, you don't even need DIR in order to test.
Drive the GPIO high to turn on the LED in the optoisolator, which asserts that signal. You could even test by connecting PUL- to Pi GND and a flying lead to 3.3V on the Pi. Tap the flying lead on PUL+ to generate 3.3V pulses which should make the stepper move.
If this is a commercial product I wouldn't rely on 3.3V signals (assuming it works) but it's fine for testing/evaluation. I would use 5V signalling with a transistor buffer here. No need for the 12V supply.
Frankly I'd experiment with a 3.3V drive to the control pins PUL and DIR, and get rid of the MOSFETs and 12V PSU. Since the inputs are just optoisolators I'd suggest that 3.3V would be sufficient to activate them.
I'd set the driver voltage to 5V, connect PUL+ and DIR+ to two GPIO pins on the Pi, and connect PUL- and DIR- to Pi GND. In fact, you don't even need DIR in order to test.
Drive the GPIO high to turn on the LED in the optoisolator, which asserts that signal. You could even test by connecting PUL- to Pi GND and a flying lead to 3.3V on the Pi. Tap the flying lead on PUL+ to generate 3.3V pulses which should make the stepper move.
If this is a commercial product I wouldn't rely on 3.3V signals (assuming it works) but it's fine for testing/evaluation. I would use 5V signalling with a transistor buffer here. No need for the 12V supply.
Statistics: Posted by ame — Sun Mar 16, 2025 10:40 am