Digital outputs are binary outputs (0 or 1, also called as high and low level) from the PLC. It is a processed control output from the PLC to the field. It is used to ON or OFF any piece of field equipment. It is like a contact of a relay when the preprogrammed conditions are satisfied the contacts are closed. Digital output can be used to operate solenoid valves, relays, indicating lamps or as a command to any other devices. Also, it might be used for the transfer of information in a binary code.