The DIN-9XWxR-MOD receiver communicates to a customer supplied programmable logic controller (PLC)-based system using a MODBUS serial communication interface. The DIN module acts as a slave device to the host PLC. The host PLC must poll the DIN module to acquire the remote control system’s current state.
The DIN module includes an RS-485 / RS-422 physical interface, configurable for full- or half-duplex operation (half-duplex is the default). The DIN module supports communication at 38,400 baud, eight data bits, no parity, and two stop bits.
The DIN module supports a subset of the MODBUS remote terminal unit (RTU) protocol. Inter-frame timeout is fixed at five milliseconds. The DIN functions as a MODBUS slave with a default address of 100 decimal. The device only supports four MODBUS commands:
• Read Multiple Holding Registers (function 3)
• Write Multiple Holding Resisters (function 16)
• Read Coils (function 1)
• Write Multiple Coils (function 15)