Modules Affected

Moto 1.0 Build 7 and earlier.

Problem

A BrainStem Moto 1.0 module incorrectly updates the 32-bit encoder count when the setpoint changes.  The actual distance traveled by the motor will be higher than that reported by the 32-bit encoder counts.  This problem applies to both channels.  It affects trapezoidal ramp operations and distance measurements obtained by reading the 32-bit encoder values.

Work-Arounds

There is no way to eliminate this error entirely.  Every setpoint change has the potential to introduce some error.

Using slow speeds and short PID periods will minimize the error.  When performing a trapezoidal ramp operation, the error can be decreased by making the ramp acceleration step time (ACCDT) large compared to the PID period.