PURPOSE: To establish the selective contrl unit in which the back up function can easily be attached, by providing the manual operaion circuit which produces the sam signal as the selective drive instruction from the control eletronic computer as manual drive control signal.

CONSTITUTION: When the OFF line mode is selected with the operation of the of the operation panel 12, the selective drive signal C1 from the control calculator 11 to the decoder circuit 22 is selected to the manual operation circuit 35 with the OFF line selection switch CH1, and the output selection code signal C7 of the circuit 35 is given to the circuit 22. Further, the application and interrruption signal C6 from the operation panel 12 to the output control circuit 28 is selected to the circuit 35 with the selection switch CH2. Thus, the signal C3 the same as the selective drive signal from the computer with the relay panel output circuit 26 is given to the local circuit 1 with manual selection. Accordingly, the number of outputs of the computer can be reduced and the manual operation can incorporate to the computer in hardware, allowing to attach the back up function easily.