Hello everyone!
I’ve recently bought two drv8825 for control two stepper motor for an application. Eveything works fine.
Next I tried to control current from winding from a microntroller using a DAC. So, I remove the potentiometers from the board and change them with DAC outputs from microcontroller. I can control current but my surprise was I’m getting a noise from the motors using DAC output.
So, with potentiometer no noise and with DAC quite noisy.
I really need to control current winding from a microcontroller.
Are AVRF and BVREF voltage inputs??
Should I use a digital potentiometer??
Any suggestion??
Thank you!
BR,
daniel
Hi, Daniel
AVREF and BVREF are used to sense a voltage as described by equation 1 in the “Current Regulation” section of the DRV8825 datasheet. Where are you seeing the noise? How are you measuring or seeing the noise? Could you post pictures of how you have your DAC connected to the board?
By the way, you might consider using our Tic stepper motor controllers to control the current of your motors from a microcontroller. The Tic T825 uses a DRV8825 driver and adds extra high level control options like position or speed control.
-Claire
Hi Claire,
Well the noise, it is an audible noise. With potentiometer the system is very quiet and interfacing with DAC I’m getting an audible noise with the motor stopped and running.
I’m using a feather M0 to interface with drv8825. All control and power pins are the same, I just remove the potentiometer and soldered a cable that goes to A0 (DAC output) of the feather M0. For the moment my application is mounted on a protoboard, so I’m available to change the drv8825 with potentiometer and with the cable soldered quicly. So, with the same situation, just changing an original drv8825 with my modification I’m getting the audible noise.
I’ve measured the voltage with oscilloscope and I noticed that the voltage from DAC seems to be cleaner than potentiometer…
Yes, I can make some pictures about my application and oscilloscpe captures.
Thank you!
BR,
daniel