This module (shield) is designed for installation on electrical switchboard. It features 4 electromagnetic relays to control almost any household electric device: lights, roller shutters, electrical sockets. It also uses 4 analog current sensors to provide independent measurement for every output.To use this module you need a RS485 MCU Module.Technical Specification:4x SPDT electromagnetic relay (G5Q-1-EU 12VDC),4x ACS712-20A analog current sensor,4 channel optocoupler for optoinsulation,5V power regulator to power up the logic,12-pin interface for RS485 MCU Module,5-pin interface to connect external LEDs,12x screw terminal for relays,4x screw terminal for RS485 connection (12V, GND, A, B),2x screw terminal for additional power source for full optoinsulation,2-pole dip switch to choose desired power source for electromagnetic coils (single or separate power source),Maximum power consumption (including RS485 MCU Module) ~2 W,Size of Raspberry Pi (85x56 mm).AC contact rating: 10A/250VACDC contact rating: 5A/30VDC