Different Modern Robotics Motor Controllers run the motors at different speeds.

[markshancock]

Our Team is running Modern Robotics Core Motor Controllers and AndyMark NevrRest40 Motors.
The Robot uses 4-wheel drive; and, ever since we changed the RunMode of the motors to be RUN_USING_ENCODER, we have had problems with the motors not all running the same speed.

This weekend we identified the problem was the firmware in one of the Modern Robotics DC Motor controllers. We updated the firmware on all the Motor Controllers and now the Motors are all running the same speed.

[Alec]

Likely cause of motors running at different speeds is that PID parameters were not set set properly. Use the Core Device Discovery App to set the PID parameters of both motor ports to AndyMark. I believe PID parameters default to Matrix motor. Also, double check PID parameters frequently. They tend to randomly revert to Matrix. Updating the firmware likely caused all ports to revert to Matrix PID parameters.

[markshancock]

I thought configuring the motor as an Nevrest40 caused to correct PID parameters to get set.
How do you force the PID config? Just do it in init?

[Alec]

I thought configuring the motor as an Nevrest40 caused to correct PID parameters to get set.

Yes.

How do you force the PID config? Just do it in init?

Yes, but only for the REV hub. For the Modern Robotics motor controller, you can only set PID coefficients via the Core Device Discovery App; not from your opmode.