SD540 Motor controllers won't run in reverse

[tdbroun]

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