A unit can include a power supply interface; a processor board power interface operatively coupled to the power supply interface where the processor board power interface operatively couples to and supplies power to a processor board; a serial interface that operatively couples to the processor board; a microcontroller operatively coupled to the serial interface; memory operatively coupled to the microcontroller; a motor control interface operatively coupled to the microcontroller; an optically isolated digital input interface operatively coupled to the microcontroller; a digital output interface operatively coupled to the microcontroller; and instructions stored in the memory and executable by the microcontroller to instruct the unit to receive digital input via the optically isolated digital input interface from a machine and to output motor control signals via the motor control interface to at least one motor of the machine.