A printed circuit board for dividing a single digital signal from a field and supplying the divided digital signals to dual digital input modules according to the present invention includes a field connection unit which has a first electric module connected to an external device installed in the field through a cable; a first digital input module connection unit which has a second electric module connected to a first digital signal input unit (DI) of a control unit through a cable and a third electric module connected to a first power line; a second digital input module connection unit which has a fourth electric module connected to a second digital signal input unit (DI) of the control unit and a fifth electric module connected to a second power line; a first circuit unit which includes a first current limit circuit module for making a forward current transmitted from the field connection unit to the first digital input module connection unit constant and a first backward flow prevention diode for preventing
