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Project design

    Datahub Modbus_TCP Protocol Illustration

    How to Build up Datahub ModbusTCP Connection

    1. Follow datahub1000 installation guide to register Solaxcloud monitor account.


    2. Get the datahub IP address. For WiFi connection, get the WiFi IP address, for LAN connection, get the LAN IP address. There are two ways to have the datahub IP address, you can login monitor account and follow below screen shot to check the IP address, or connect to datahub WiFi signal, use local mode to login to check the IP address. (For the early generation datahub please login, please contact us to confirm the generation).

    3. Use PC or laptop to connect to the same home router that datahub connected, open modbus software to input the IP address, start to inquiry the register data.


    Data Reading

    DataHub has 4 485 ports, each string is connected to a maximum of 20 devices, of which each device has a common read register address of 40, so the total number of registers under each serial port is 40*20 = 800. 


    Reading RS485 communication address starts from 35000, so the starting address of the four serial ports is: 35000, 35000+800, 35000+800*2, 35000+800*3, and the modbus address of the device needs to be calculated through the formula.

    You can query the address of the parameter you want to know through this formula: 

    Start address + (serial port number-1) * 800 + (device address-1) * 40 + offset

    The offset can be viewed by yourself according to the table below.

    (This table is for modbus function code 04.)

    For example,

    1. Address query

    Now I want to know the start address of the third device under serial port 2. The starting address should be:

    35000+(2-1)* 800 +(3-1)*40 = 35880

    (Since each device has a common read register address of 40, the 35880-35919 are all this device’s address. Apparently, the next one’s (the forth device under serial port 2) starting address is 35920. )

    2. Parameter Address

    Now I want to know the address of the AC side grid frequency of the third device under serial port 2. The address should be:

    35000+(2-1)* 800 +(3-1)*40 + 6 = 35886


    Data Writing

    At present, DataHub only supports 06 single write, enter the value to the corresponding offset address.


    Software Operation: Use the software Modbus Poll

    1.  Connect to Datahub.

    (1) Click Connection, select Connect, and the interface will pop up

    (2) Select Modbus TCP/IP

    (3) Enter the IP of DataHub

    (4) Click OK


    2.  Query Inverter Information

    (1) Select Read/Write Definition...

    (2) Select 04 Read Input Registers (3x)

    (3) Enter the calculated start address of the device you want to query

    (4) Enter the query length (40 registers per machine, up to 125 registers per query)

    (Which means you can query no more than 3 device at a time)

    (5) Click OK


    3.  Returns the Results

    4.  Data Write

    (1) Select 06: Write Single Register

    (2) Enter the register address to be written

    (3) Enter the value written by the register address

    (4) Click Send

    (5) Return Response OK to write successfully.



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