CONTROLLER

PROBLEM TO BE SOLVED: To improve the performance and noiseproof property of an arithmetic operation in a controller having respective control units duplicated or multiplexed to mutually independently perform the same arithmetic operation. SOLUTION: In the controller CS made redundant by a control unit 2 and a control unit 1 mutually connected through a backboard bus 3 in a communicable way, the respective control units have a communicating part 14 which always mutually transmit and receive a permanent frame between a synchronizing register 15 for storing synchronization processing data and the control unit 12 and can directly access the synchronizing register 15, wherein the communicating part 14 transmits and receives data about synchronization stored in the synchronizing register 15 to/from a control unit of a connection destination by using the permanent frame. COPYRIGHT: (C)2008,JPO&INPIT