8-in-8-out Modbus Relay Communication Protocol Description

Communication Protocol Description

This product supports standardsmodbusA part of the instruction, supportmodbus-RTUControl relay on/off, Display input status, Other functions are not supported! Detailed instruction generation and parsing methods, You can refer to the Chinese version of the protocol based on the register table in this articleMODBUSThis product supports function codes.

Broadcast address: 01, 02, 03, 05, 06, 15, 16

Operations on broadcast addresses245, Will operate all modules on the bus, Function code.

Read the status of the relay01: Register address 0 represents the first path, Representing the second route, 1Function code;

Read the status of switch input02: Register address 0 represents the first path, Representing the second route, 1Function code;

Operate the status of a single relay05: Register address 0 represents the first path, Representing the second route, 1Function code;

Operate the status of multiple relays15: Register address 0 represents the first path, Representing the second route, 1Function code,

All follow the above rules and so on01/02/05/15Function code.

Read the values of multiple registers03Function code

Write the value of a single register06Function code

Write values for multiple registers16The register addresses corresponding to the above three function codes are as follows:

Register address:
Saved the address of the local machine to support reading and writing: 0 Support function code, Register address03, 06, 16
The saved input state only supports reading: 500 Address, Representing the500Road1-16Address, Representative501Road17-32Based on the input quantity, and so on, Support function code. Register address03.

Starting from this register address, the status of the output relay is saved: 10 00Address. Representing the10 00Road1-16Address, Representative10 01road17-32road, According to the number of relays, and so on. Support reading and writing, Support function code03, 06, 16

Register address: 15 00Starting from this register address, the values of internal variables are saved. Address15 00Representing internal variables1, Address15 01Representing internal variables2, and so on, Support function code03, 06, 16, Instructions can only read or write one internal variable at a time.

Use function codes01Read the status of the relay

Use function codes02Read the status of switch input

Use function codes05Operate the status of a single relay

Use function codes15Change the status of multiple relays