USR-M511 Modbus Command Store and Modbus Management


This manual introduces USR-M511(Modbus Gateway, Modbus RTU to TCP) Modbus command store function and Modbus management function.

1. Modbus command store

1.1. Introduction

Enable Modbus command store function can accelerate query speed of network Modbus master and this function is suitable for multi-master query mode. The application diagram as follow:

Modbus command

1.2. Configuration

1.2.1. Hardware connection


Power M511 and connect M511 Ethernet interface to PC or to same router as PC. If user connects M511 Ethernet interface to same router as PC, user should configure M511’s static IP address to in same network segment as router as follow( is router gateway address in our test):

Hardware connection

User should use setup software USR-TCP232-M4K3-setup-V2.3.3.97.exe to configure M511.

1.2.2. Configuration

Step 1: Open browser, type in M511 IP address( in our test) and log in with username and password both are admin(Default of username and password both are admin).



Step 2: Configure Modbus command store as follow(After configuration, please click ‘Save’ and restart module):

Configure Modbus command store

Ø  Store function can only works to Modbus slave

Ø  Store function just query and update storage for command which be configured

Ø  Stored command that be configured can only enable automatic query and store function after querying of network Modbus master

Ø  The frequency of command query is related to serial baud rate. For example, baud rate is 9600, the query frequency of RTU protocol is about 400ms and the query frequency of ASCII protocol is about 800ms


Ø  If query command of network master and query command that be configured have inclusion relation, response data from network will be the data from internal cache. For example, query command 1 is 01 03 00 00 00 0A C5 CD and query command 2 is 01 03 00 0A 00 14 65 C7, user can configure as follow:

query command 1 is 01 03 00 00 00 0A C5 CD and query command 2 is 01 03 00 0A 00 14 65 C7

And any one command of above two commands query slave device, it will get fast and accurate response from internal cache.


Note: Quantity must less than 126(According to Modbus protocol)

2. Modbus management

2.1. Introduction


Modbus Gateway M511 can manage Modbus slave devices which is mainly applied to monitor data of specified device. And parameters configuration on Modbus management web page will take effect immediately. Modbus management is based on Websocket. So user needs to use browser which can support Websocket as follow:




Version 4+


Version 4+

Internet Explorer

Version 10+


Version 10+


Version 5+

2.2. Configuration


Step 1: User can refer to 1.2.1.Hardware connection and 1.2.2.Configuration Step 1 to enter M511 Web Server.


Step 2: Enable Modbus command store function and configure stored command as 1.2.2.Configuration Step 2.


Step 3: Open Modbus management web page and set the command(Command must in range of stored command in Step 2).

Open Modbus management web page and set the command

Step 4: Click ‘Save’ and refresh web page. Configure remark parameters for convenience of reference(Remark only be allowed to use Chinese character, letter and number). Then user can monitor data.