DMC01 Protection?

Hi Folks,

I’m enjoying my new DMC01 on a differential drive robot project!

Its driving a pair of Pittman gear motors. I’m totally impressed with the smooth control it provides right out of the box…with the default RC settings. Plug and Play…literally. The single joystick option is awesome…it just works perfectly to control our bot.

I’m wondering what protections are built-in on this board.

I notice that when backdriving the motors with the board powered off, the LED’s light…both the 2 motor LED’s and the blue power LED. Is there protection for current from backdriving motors?

13A is about the stall current for my motors according to the data sheet. Could you summarize the overcurrent protection in case the drive exceeds 13A? I’ll plan to fuse the motors at 12A…but I’m wondering how robust this board is.

Any other protection details? How about the auxiliary motor…planning to hook that one up to another Pittman motor of the same size.

Overall, could you summarize how other folks have smoked these boards, and design considerations to avoid?

Thanks! Jeff

Hello, Jeff.

The TReX Dual Motor Controller DMC01 uses the Dual VNH2SP30 Motor Driver Carrier as a base. The dual VNH2SP30 motor driver carrier has reverse voltage protection and over-current protection. You can read more about these features on the dual motor driver’s product page and in the datasheet for the VNH2SP30 , which can be found under the “Resources” tab of the TReX’s product page.

From my experience, when these boards get damaged it is generally because of accidentally making a bad connection or pushing the board beyond its capabilities.

- Grant

Thanks Grant…good to see the datasheet…that’s helpful.

It looks like this board has a good amount of headroom over the current limit specs…handles current up to 50A typical.

For backdriving, I still have a concern. The lights on the motor controller board light up when the motors are back driven. The LED’s for the motors don’t surprise me, but the blue power LED kinda does…the voltage from the motors is making its way back to the boards power supply.

Is there some protection for the motor controller to handle the power coming in from the motors?

Having the power from the motors go to the power rails is in some sense a protection. It’s generally not a problem unless you backdrive the motors faster than they can go when you power them. For instance, if you get 200RPM at 12 V, you’d have to spin the motors faster than 200RPM to generate more than 12V, which typically doesn’t happen.

- Grant

Thanks Grant…good to know. Must be that the blue LED comes on well below 12V…doesn’t take much backdriving to light it up.

I’ll check the voltage while backdriving. I assume its OK up to the max voltage for the board…which I think is 16V?

Yes, it should be fine to backdrive the motor as long as the voltage does not exceed the board’s maximum voltage rating.

- Grant