DIGILENT MOTOR CONTROLS

[VIKotic Dave]

Just received 6 Digilent DMC-60 motor controllers. Excited to get them on test bot. Anyone one else out there trying out the new motor controllers?

[Richard Wallace]

There were a few comments about this controller in an earlier thread. The NI website says it is a drop-in replacement for the Victor SP, all the specs are the same, and the Victor's price is $10 less. NI has great products and they are a long-time FIRST sponsor/supplier. CTRE and IFI are innovators that have raised the bar for FRC robots in many ways, for many years.

All of the above considered, I am not seeing a reason to look into the DMC 60 controller any further. Does anyone have comparative data to change my mind?

[Kevin Sevcik]

Looks like the digilent has about $10 of smarts that might make it more desirable for non-FRC applications. It has integrated overheat protection where it chokes the throttle when the internal temperature exceeds 70C. Also it has 4 LEDs that flash CW or CCW at varying frequency depending on throttle and direction. Which might look a few bucks more awesome than two blinky lights?

EDIT: Also has current foldback which if it's not a funny name for the thermal overload protection, should reduce voltage as current demand increases, protecting the breaker, controller, and motor from damage from over current. Not sure how this would affect start-up and pushing torque in a drivetrain situation. Would be interesting to see its characteristics with a motor hooked up to a dynamo.

[Tom Line]

I hadn't looked into that motor controller, but it looks amazingly like the Talon/Victor, right down the flat section that appears to be for a future plug-in expansion in the same location as the Talon and Victor. After reading the other thread about how it's a clone, I'm a little surprised. Why would FIRST allow a blatent copy of a product like this?

[mman1506]

Originally Posted by Kevin Sevcik

Looks like the digilent has about $10 of smarts that might make it more desirable for non-FRC applications. It has integrated overheat protection where it chokes the throttle when the internal temperature exceeds 70C. Also it has 4 LEDs that flash CW or CCW at varying frequency depending on throttle and direction. Which might look a few bucks more awesome than two blinky lights?

EDIT: Also has current foldback which if it's not a funny name for the thermal overload protection, should reduce voltage as current demand increases, protecting the breaker, controller, and motor from damage from over current. Not sure how this would affect start-up and pushing torque in a drivetrain situation. Would be interesting to see its characteristics with a motor hooked up to a dynamo.

Has anyone ever had a victor or talon fail during normal usage? I've never even seen one get remotely hot. Are these features necessary?

[tr6scott]

Originally Posted by mman1506

Has anyone ever had a victor or talon fail during normal usage? I've never even seen one get remotely hot. Are these features necessary?

If by Normal, you mean when you reverse the input polarity, then yes we have seen them fail...

If that is not in your definition of Normal, then no, we have never had one fail once it survived our initial wiring, and I have probably a dozen 1st generation, talon SR's that have been beat up on practice bots for years now.

[Kevin Sevcik]

Originally Posted by mman1506

Has anyone ever had a victor or talon fail during normal usage? I've never even seen one get remotely hot. Are these features necessary?

The Victor SP has a sustained current rating of 60A. In an FRC application, it's protected by a breaker that will trip after at most 47 seconds at that load. It's already over specified for an FRC application. So no, I don't think thermally overloading Victors is a common occurrence in FRC.

On the other hand, the world is bigger than FRC, so I suspect there is in fact a market for a controller that is $20 cheaper than a Talon SRX but has enough smarts to protect itself from overcurrent and overheating.