Abstract: The present invention relates to control architecture for a centrifuge motor speed control system having dual processors. The processors are configured in a master-slave relationship for some predetermined subset of instrument control functions during the execution of which the slave operates under the direction of the master to effect that subset of control functions. However, each of the processors is independently responsive to a speed signal from a tachometer and is independently capable of controlling the additional instrument control function of conditionally coupling the motor to a source of energy.