VEX Motor Controller

The VEX Motor Controller is a device which converts a standard logic-level PWM servo control signal into motive power to drive a Motors.

This article is only relevant for old VEX Cortex system, which is no longer competitive.

A motor controller is not required for the VEX Cortex ports 1 and 10.

The VEX Motor Controller performs the function of an H-Bridge. Its FETs, or power output transistors, have a low enough ON resistance to not heat appreciably, even when controlling a stalled motor. VEX Motor Controllers add an additional 24 inches of wire onto a motor, which can be a blessing to avoid a PWM extender or a curse when managing short wire runs.

VEX Motor Controllers are driven using a standard hobby servo control scheme, with a 1 ms pulse running full reverse, a 1.5 ms pulse stopping the motor, and a 2 ms pulse running full forward. A non-standard 200 us pulse will engage an active brake. These pulses typically appear on a 20 ms (50 Hz) duty cycle, but faster update rates up to 300 Hz may be possible with PROS.

Teams Contributed to this Article:

• BLRS (Purdue SIGBots)