PURPOSE: To shorten the time from input to display by quickly performing the processing of recognition of the state input from a sensor switch and display of state data in each input/output control part.

CONSTITUTION: The state signal from the sensor switch is recognized by keeping the input state effective for a certain time in an input circuit of an input/output control part 5, and the result is stored in an input/output control circuit 7 to perform the state management and is reported to not only an input control circuit 6 but also an output circuit 9 to display the state on a display part 10. Consequently, the processing of input and display is performed in the input/ output control part 5. A central processing part 4 scans the state with each input/output control part as the unit, and the instruction of scan indication is decoded by an output control circuit 8 of each input/output control part 5, and the input control circuit 6 receives this instruction to transmit state data to the central processing part 4 through a bus. Thus, the time from input to display is shortened to reduce the load of the central processing part.