Can't set DRV8825 to enough current

Support Motor controllers/drivers and motors
1

Greetings,

I’m working on my first CNC project, using a Theremino controller and CNC shield with 4 DRV8825 drivers for NEMA 23 stepper motors. I haven’t tried the motors yet, as I’m stuck trying to set the proper current on the 8825 drivers.

I’ve followed the instructions on the video on how to set the current limit, but the problem is that I can’t get any reading above 80 mA on any of the 4 drivers for any setting of the potentiometer. My power supply to the board (and the drivers) shows 24.2V.

According to my estimate, I would want to get around 1.6A from each driver, but I can’t get anywhere near that. I have tried two different multimeters with the same result.

Thanks for your help.

Dave

2

Hello, Dave.

How are you measuring that 80 mA current? What did you set the VREF voltage to and how did you measure that? Is there a datasheet for your motor you could link to here or, if not, what is the voltage and current ratings for your stepper motors or the resistance of the motor coils?

-Nathan

3

Thanks for your prompt response, Nathan.

I just read the instructions for my project and watched Pololu’s setting the VREF video for the 17th time, and realized that I’m an idiot. I was measuring current at the top of the potentiometer, and not voltage. Do’h.

Noobie!

Dave