Replace Arduino with PLC as stepper controller

Hey all.

I’m currently able to control my stepper motor by utilizing an Arduino Mega 2560 hooked up to a stepper driver. The Arduino works great with the stepper driver since the control pins on the driver are normally operated at 5V. However, I would like to substitute the Arduino with my 24V signal output PLC, and have therefore decided to mimic the connections with my PLC. The stepper driver’s user manual states 24V CAN be used to signal to the driver as long as a 2kohm resistor is used in series with the control pins. Nonetheless, I have been unsuccessful in operating the stepper motor with the PLC output. :confused:

Attached are pictures of my Arduino circuit with the stepper driver to control the motor, as well as info on the driver’s control specifications. When I attempted to operate the motor with the PLC, I connected the 24V digital output signal to the PUL pin, and then connect a 24V power supply to the OPTO pin. The digital output pin on the PLC is not noted as PWM, but I don’t think this should matter since I’m pulsing very slowly (about 1 step per s). Can anyone explain why I may be able to operate the stepper motor with the Arduino, but not with the PLC? Thanks for any help!!!

Try a PLC forum.

Can you show a schematic for your PLC connections?

For that connection, PLC outputs have to be SINKING (connect to ground when active), are they?

Thanks for helping guys.

dougp:
Can you show a schematic for your PLC connections?

I’ve attached an quick sketch of my PLC connection. The first sketch at the top shows my current configuration with my stepper driver. I’m purely trying to mimic my output from the Arduino setup, except that I incorporate a 2kOhm resistor. The lower sketch in the image shows a new proposed wiring configuration, but would require a different stepper driver than the one I am currently using.
Let me know your thoughts! Thanks.

Do you have the driver GND connected to the PLC GND?

JCA34F: Do you have the driver GND connected to the PLC GND?

Nope. I assumed since I didn't have the driver GND connected to the Arduino GND in any way, I didn't have to do that for my PLC setup. So I should connect the driver GND pin that I would normally connect my power supply GND to, to my PLC GND instead?

Btw, here is a picture of my pin configuration on my driver while using the Arduino. Is the GND pin you’re talking about the GND pin shown in the picture?

khills: So I should connect the driver GND pin that I would normally connect my power supply GND to, to my PLC GND instead?

Well, if the optocoupler wiring is correct, you shouldn't need a shared GND, which PLC (brand and model number)?