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modbus_tcp_client

modbus_tcp_client#

Overview#

This example demonstrates how to use Modbus TCP protocol to control board LED light.

FreeModbus supports bellow feature:

  • Read coil(0x01)

  • Read discrete inputs(0x02)

  • Read holding registers(0x03)

  • Read input registers(0x04)

  • Write single coil(0x05)

  • Write single holding register(0x06)

  • Write board LED status(0x0d)

  • Read board LED status(0x0e)

  • Write multiple coils(0x0f)

  • Write multiple holding registers(0x10)

Running the demo#

If the test passes, serial port output:

Please input Modbus Server ip address(for example 192.168.1.2):
Note: don't use backspace key or space key!
Modbus Server ip: 10.91.20.33

Initializing PHY...
[LINK STATE] netif=0, state=down
[LINK STATE] netif=0, state=up, speed=100M_full

************************************************
Modbus TCP example
************************************************
FOR TASK ETH Get IP address from DHCP...

IPv4 Address : 10.91.20.66
IPv4 Subnet mask : 255.255.255.0
IPv4 Gateway : 10.91.20.254

Enable LED1
0 1 0 0 0 6 1 13 0 0 0 1
Enable LED2
0 1 0 0 0 6 1 13 0 1 0 1
...

Use the MIMXRT1180-EVK board as modbus Server simulator, write board LED status(0x0d) to control LED light

Supported Boards#

MIMXRT1180-EVK
Hardware requirements

  • Mini/micro USB cable

  • Network cable RJ45 standard

  • MIMXRT1180-EVK board

  • Personal Computer

Board settings

No special settings are required.

Prepare the Demo

  1. Connect a USB cable between the host PC and the OpenSDA USB port on the target board.

  2. Connect network to the target board(ENET4) via an Ethernet Cable.

  3. Open a serial terminal with the following settings:

    • 115200 baud rate

    • 8 data bits

    • No parity

    • One stop bit

    • No flow control

  4. Write the program to the flash of the target board.

  5. Press the reset button on your board to start the demo.

IMX943-EVK
Hardware requirements

  • Mini/micro USB cable

  • Network cable RJ45 standard

  • IMX943-EVK board

  • Personal Computer

Board settings

No special settings are required.

Prepare the Demo

  1. Connect a USB cable between the host PC and the OpenSDA USB port on the target board.

  2. Connect network to the target board(J25) via an Ethernet Cable.

  3. Open a serial terminal with the following settings:

    • 115200 baud rate

    • 8 data bits

    • No parity

    • One stop bit

    • No flow control

  4. Download the program to the target board.

  5. Either re-power up your board or launch the debugger in your IDE to begin running the example.

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