Patent ID: 8858494

Claim:
An infusion pump assembly having a reverse rotation prevention system, said assembly comprising: a roller assembly configured to rotate forward to pump fluid at a flow rate; a coil configured to generate a coil field in response to a coil voltage; a rotor configured to generate a rotor field that cooperates with the coil field to urge the rotor from a first rotor position toward a second rotor position, said rotor field having a polarity, said rotor being rotationally coupled to the roller assembly such that when the rotor is urged toward a the second rotor position the roller assembly is urged from a first roller assembly position toward a corresponding second roller assembly position for movement of the rotor in a first direction; a rotor position sensor arranged to output a rotor position signal indicative of the polarity; and a controller adapted to receive an infusion schedule, receive the rotor position signal, determine the flow rate based on the infusion schedule, output the coil voltage based on the flow rate and the rotor position signal, and detect a change in the rotor position signal, wherein if a change in the rotor position signal is detected when the flow rate is zero, the controller outputs a coil voltage effective to hold the rotor in place and thereby prevent reverse rotation of the roller assembly in a second direction, opposite the first direction.