The 4R-D7 module allows you to control 4 relays using the Modbus RTU protocol. Communication with the device can take place via the RS-485 or UART TTL interface.
In addition, the device has 4 control inputs protected with optocouplers (input voltage range: 3.3 V ... 30 V). The voltage from the control inputs is not the voltage directly supplying the relay coil.
Attention! The selection of the control interface is made by means of jumpers placed on the board. It is not possible to control the outputs using both communication paths simultaneously.