SD540 Motor controllers won't run in reverse
 

We have encountered a problem with the new SD540 motor controller and were wondering if anyone else had experienced it. We chose to use these controllers exclusively because of the reduced footprint of the 4 bank model. Like every other low bar bot, robot space is at a premium and this unit puts 4 controllers in the space of 3.

The problem is that we cannot get the motors to turn in the reverse direction. We executed the calibration procedure multiple times. We changed to different PWM ports on the RoboRio. We created a brand new project just for testing to remove the possibility of anything else we had in our code from impacting the controllers. We verified that there is a PWM signal coming from the RoboRio. The controllers just don’t respond to signals in the reverse direction. We already swapped out the 4 bank controller unit with another and got the same results (after callibration). When we put a Talon SR in its place, it worked flawlessly. Any ideas before I scrounge up 8 motor controllers and try to find space for them on an already jam packed robot?

Thanks
Tim

Re: SD540 Motor controllers won't run in reverse
 

Tim,
If the controller is satisfied with the calibration procedure, then you likely have a hole in your software. When you expect the motor to reverse, what is the motor actually doing? Is it moving or is it just stationary? Be aware that limit switch input may affect operation. Also check the position of your DIP switches on the bottom.

Re: SD540 Motor controllers won't run in reverse
 

The fact that the software works flawlessly with a Talon SR eliminates our software as a root cause. (unless my problem solving logic is flawed) We put a multi-meter on the pwm signal line and verified that we are sending a voltage in both directions (although the values escape me at the moment).
When we send the reverse signal, there is no response from the controller.

We have nothing attached to the limit switch pins, and they are set to normally open.

Re: SD540 Motor controllers won't run in reverse
 

Tim,
The DIP switches also affect operation on this controller. The limit switch, when sensed, may prevent motor operation in one direction. The controller could be fooled into thinking it is beyond the limit in that direction and therefore will prevent control in that direction.

Re: SD540 Motor controllers won't run in reverse
 

What model multimeter did you use, and did you have it set to AC or DC?

See this post, and then this one.

Re: SD540 Motor controllers won't run in reverse
 

You can watch the behavior here on a bench with a signal generator and an oscilloscope. First calibration, then normal operation. Cycling of power, then no reverse.

https://www.youtube.com/watch?v=xaKI...ature=youtu.be

Re: SD540 Motor controllers won't run in reverse
 

Update!

The manufacturer has replied that they have reproduced this condition and are making firmware changes to correct it.

Thanks for your efforts to help us out.

Tim

Re: SD540 Motor controllers won't run in reverse
 

Nice video, thanks.

Don't know if this has anything to do with the problem you are seeing, but it doesn't look like you are waiting a full 5 seconds when you are calibrating.


Can users update the firmware themselves, or do they have to ship the units back to mindsensors?

Re: SD540 Motor controllers won't run in reverse
 

Users can upgrde the firmware themselves, the instructions to upgrade are here: http://www.mindsensors.com/blog/how-...roller-for-frc