This is a pretty obscure one to troubleshoot: we found the following and are looking for a way to fix the issue...

In essence this appears to be a bug in the bFloatDuringInactiveMotorPWM setting in relation to the Tetrix Motor Controllers.

In order to get the "bFloatDuringInactiveMotorPWM = false;" (brake when the motor is not moving) functionality, the nxt and the controllers must be started in the following order.

1. Power (12V) on to the controllers.
2. Turn on NXT
3. Start Program

if the NXT is on (even if no program is running), and the Tetrix controller 12V power is cycled, when the program is started, the motors attached to the controllers automatically float when a zero power is sent. Also the encoder PID seems to stop working.

We've tried putting the bFloatDuringInactiveMotorPWM command (even setting it true, waiting, then setting it false) into the program. We've tried the PID setting commands too...

So... Is there a way to have the NXT re-send the initial power-up configuration to the Tetrix controllers? or?

Any one got experience or a solution to this?

I thought that the "bFloatDuringInactiveMotorPWM" command was only for the Lego motors.

While that may be true, the same function is active on Tetrix motors too.

We have a procedural solution that our team uses religiously now... if the 12V power ever gets shut off, then NXT must also be turned off, and then turned back on only when the 12V is on first...

It's a pain, but we get PID controlling zero speed on Tetrix motors that way.

It seems like there should be a software solution, but we haven't seen one yet.