Setting and checking incident light intensity for digital sensors FX-501/502/301/305, LS-501/403, DPS-401/402 and input unit SC-A01/A02/T1JA that are scattered inside and outside equipment can be carried out remotely for all sensors by using Panasonic SC-GU1-485, which greatly improves ease of operations such as monitoring equipment that is running and also equipment starting and maintenance. RS-485 communication provides a high level of general compatibility so that any type of PLC can be used. Integration with existing systems is possible without the need to change PLCs. High-speed communication at a maximum speed of 57.6 kbperator to instantly check information such as the incident light intensity and output statuses of the digital sensors. A maximum of 31 nodes can be connected in series. This is ideal for flexible handling when the sensors are to be installed in scattered locations or if more sensors are added. Up to a maximum of 16 sensors can be connected side by side. Power can be supplied to all of them at once, so that less wiring and installation work is required. Wire-saving connectors also makes it possible to send output signals to the PLC in a single batch.