Product introduction
ADM-4108R is a 8 channel relay switch output module, which is used in the signal control of industrial device. Support 8 channel A type normal open relay output, the relay capacity is 3A @250VAC/30VDC. RS-485 communication interface, support the MODBUS RTU protocol, can connect configuration software, PLC, DCS industrial control touch screen.
Product specification
Switching Output
1. output channel: 8 channel A type relay output
2. Load voltage: 0~250VAC or 0~30VDC
3. Load current: 3A
Communication interface
1. Communication protocol: MODBUS-RTU
2. Interface type: RS-485 interface
3. Interface protection: 15KV ESD protection, 1500V isolation protection
4. Baud rate: 1200/2400/4800/9600/19200/38400/57600/115200
5. Parity ：None, even, odd
6. Default: 9600, N, 8, 1 (modifiable)
System parameter
1. Module size: 104mm x 72mm x 26mm
2. Installation: 35mm din rail installation
3. Environment: temperature: -20~70℃ humidity: 0-95%, not condensing
4. Power supply: DC9~30V is less than 3W
LED indicator definition
1. POWER: power status indication, "bright" power supply is normal
2. COMM: RS-485 communication indication, that "flash" is sending and receiving data
3. RO0~RO7: relay action indication, "bright" relay is closed
Using the default communication parameters
When you forget module communication (ID, baud rate, parity bit), the INIT and VS- pins are short circuited, module electrifying, The communication parameters of the module are (9600, N, 8, 1), ID is 1.INIT and VS- pin is disconnected, module using parameters set by the user, default parameters for the module (9600, N, 8, 1), ID is 1.
Module register address description
1.00001~00008: relay output register address (0x),
Use 01 and 15 function code 0000H~0007H.
2.40161~40163: module parameter register address (4x),
Use 03 and 06 function code 00A0H~00A2H.

MODBUS-RTU Protocol communication format
Write the output value of the 8 channel relay (16hex)
Host sending ：01 0F 00 00 00 08 01 0F BE 91
01(ID)        0F(Function code)    00 00(Start address)   00 08(Total register)
01(Total byte )        0F(The value that is written, 0F is RO0-RO3 output 1 and RO4-RO7 output 0)     BE 91 (CRC Code)
Module return ：01 0F 00 00 00 08 54 0D
01(ID)        0F(Function code)     00 00(Start address)   00 08(Total register)
54 0D (CRC Code)