SM2-RM has 3 digital inputs DI. It is easy to connect movement sensor, surge, optical barrier, door sensor and various other devices that use contact inputs to indicate its status.
These 3 digital inputs can also be used for reading values from electro meter, water or gas meter on condition that the meters have pulse output SO.

Bring supply signal DC- on DCOM terminal. Voltage between terminals DCOM and DI (DI1-DI3) must be higher than 8V in order to switch on the input.