Does it matter where to plug in motors?

My team’s robot utilizes 9 motors, but strangely enough ports 1, 2, 3, 4, 5, 6, 7, 8, and 10 are occupied and port 9 is empty. I always assumed that you could just switch around the motors in their ports and reconfigure them in the robot’s programs.

My question: does it make a difference in which port a motor, or a sensor, is plugged into the Cortex?

Last year, we found that the 2-wire ports 1 and 10 have significantly less power than the 3-wire ports with MC29s. For some people there is no noticeable difference, but we noticed it a decent bit.

I would try to avoid using 1 and 10, or at least make sure the lift or drive doesn’t have a mix of 2 and 3 wire motor ports, if it’s possible.

How did you determine this? The components used for the H-bridge that drives ports 1 & 10 are identical to those in an MC29.

Ports 1 & 10 also work better when used in closed loop control (ie. PID control) as they allow a much faster update and are not affected by the inherent delays when using the RC pwm ports.

See this old post.

Does the same thing apply to sensors?

I don’t fully remember how we found it out, but it wasn’t anything quantitative. I think we had both two wire ports on one side of the drive and it curved to that side, and upon flipping the ports it curved to the other side. We also noticed something with the motor on it’s own in a 2-wire versus 3-wire port, but it was all just qualitative observations.

It was nothing major, but somehow we managed to notice it and it had an effect. I don’t think it really will matter, but I still try to keep the different ports on separate systems. Anyways, I’ve always wondered why the Cortex has the two 2-wire ports instead of all 3-wire?

Sort of. Digital ports 4 and 10 share the same interrupt, which can lead to things not working (not reading or resetting, not sure?) when both are used. See this thread:

Edit: Oh, and there is a speaker port labelled SPK at the bottom of the sensor ports, it’s not for a sensor, and the only place you plug the speaker in! I felt really stupid last year when I always read about some speaker port and couldn’t find it while staring straight at it… :stuck_out_tongue:

It doesn’t it will work but you want to break your motors in half page 1-5 is one bridge and the other is ports 6-10 so we take two motors from each side for our power expander.