It then interprets it in itself and transfers it to other devices that it commands in the field. Collection and transfer of information can be done analog or digitally. For example, data from the sensor can be transferred to a valve. PLCs should be preferred if the system to be controlled is larger and requires more operations. It can also be devided into many types like Ewelink Smart Relay, Tuya Smart Relay and so on for different models. http://www.hochiot.com/smart-relay/tuya-smart-relay/