Condition:New
Type:Logic ICs
Model Number:MB8RO
Operating Temperature:-10 to +55
type of output:8 normally open relay output
Load capacity:250V resistive load 3A inductive load 1A
Communication type:RS485 MODBUS-RTU
Characteristic:Signal acquisition, RS485 communication, the main power of mutual isol
Technology:Industrial patch design
MB8RO 8 way relay output module, relay can be controlled through the MODBUS bus, the relay can be set on the electric load prefabricated state, or set a power load last relay power down state; control interface for the isolation of RS485, using Modbus-RTU communication, direct fit PLC, DCS and domestic various configuration software.
The first chapter product introduction
A.Summary
MB8RO 8Road relay output module, the relay can be controlled through the MODBUS bus, the control interface for the isolation of RS485, the use of Modbus-RTU communication, directly with the PLC, DCS, and various domestic configuration software, etc..
The relay output, the power supply and the RS485 communication electrical signals are isolated from each other, which can effectively restrain all kinds of mode and common mode interference, and ensure the reliability of the module.
Two.Characteristic
1.Using Modbus-RTU protocol.
2.Relay output, power supply, RS485 communication electrical signals isolated from each other.
3.RS485The communication signal output interface is protected by the overvoltage and overcurrent.
4.Relay operation mode and communication format can be set by software.
FivePower polarity protection.
SixRelay output function
1)Conventional mode: on the electric load out of the preset state function, out of state power down does not save.
2)Power down storage mode: the module power off after the save out of the state, after the power up before loading off the power out of the state.
Three.Technical index
project | parameter |
signal output | 1Output channel: 8 normally open relay output 2Load capacity: resistive load 250V/2A inductive load 250V/1A 5.Relay coil and contact isolation voltage: 2000V |
Communication output | 1Communication protocol: MODBUS-RTU 2Interface type: isolated RS485 communication, the output of the interface using the overvoltage and overcurrent protection 3Baud rate: 1200BPS, 2400bps., 4800bps, 9600bps, 19200bps 38400bps57600bps, 115200bps. 4Check bit: no parity check, parity check 5. setting: module address, baud rate, parity bit is set up by the software 6Communication distance: 9600bps 1200 meters 7.Isolated voltage: 1500V |
Module size | A.Separate module size: 104mm*72mm*26mm B.With terminal and guide rail box size: 124mm*72mm*45mm |
Installation method | Standard DIN guide rail installation |
work environment | Temperature: -10 ~ +55℃? temperature humidity: 35~85%(not dew) |
Working power supply | 1Power supply voltage: 10V~30V wide range of power supply, with the power supply polarity protection 2Power consumption: less than 3W |
Four.Product appearance and external wiring diagram

Five.Module indicator lamp and switch function specification
1.POW/SET;Module working status indication
A.Green light: the module works in the running state. B. red light: the module is configured to write parameters, need to re power up.
2.TXD/RXD:Communication status indication
A.The green light flashes: the communication receives the data B. red light flashes: the module is sending data
C.The green light is always on: DATA+ and DATA- on the communication line RS485 line is connected to the reverse or the connection is broken.
3.Module right reset switch
1)When the communication parameters (module address, baud rate, parity bit) do not know or communication parameter misspecification, and can not establish contact module communication, the solution is to reset the communication parameters; we use the clip to hold the reset switch is not open, 5 seconds after the [POW/SET] module of the red indicator lights, release the reset switch, the communication the parameters have been reset, as long as the power supply module after the restart time, the communication parameters of the module has been reset.
2)Communication parameters after reset: Address: 1, baud rate: 9600bps, parity: No.
Six.Terminal definition
terminal | Name | Explain | | terminal | Name | Explain |
1 | RY5A | Relay output channel 5 | 11 | RY0A | Relay output channel 0 |
2 | RY5B | 12 | RY0B |
3 | RY6A | Relay output channel 6 | 13 | RY1A | Relay output channel 1 |
4 | RY6B | 14 | RY1B |
5 | RY7A | Relay output channel 7 | 15 | RY2A | Relay output channel 2 |
6 | RY7B | 16 | RY2B |
7 | DATA+ | RS485Communication + | 17 | RY3A | Relay output channel 3 |
8 | DATA- | RS485Communication - | 18 | RY3B |
9 | +Vs | Power input + | 19 | RY4A | Relay output channel 4 |
10 | GND | Power input - | 20 | RY4B |
Seven.Principle block diagram

Eight.MODBUSRegister description
1.Module supports MODBUS function code
Code | Meaning | operation |
0x01H | Read more than one coil register | Read the values of one or more coil registers |
0x03H | Read more than one hold register | Read one or more of the value of the register. |
0x05H | Write a coil register | Write the value of a coil register |
0x 06H | Write a single hold register | Write a data to hold register |
0x0FH | Write one or more coil registers | Write one or more of the value of the coil register |
0x 10H | Write more than one hold register | Write one or more data to hold registers |
2.Register definition description
1)Coil register0x01H,0x05H,0x0FH)
address | parameter | read/write | minimum value | Maximum value | Explain |
00001 | RO0 | Read and write | 0 | 1 | Relay output0 |
00002 | RO1 | Read and write | 0 | 1 | Relay output1 |
00003 | RO2 |


