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  • TapHome to Modbus RTU / ASCII / TCP

    Supported communication layers

    • Modbus RTU via RS485 (BUS 1, BUS 2, or BUS 3 terminals)
    • Modbus ASCII via RS485 (BUS 1, BUS 2, or BUS 3 terminals)
    • Modbus TCP (via ethernet, connecting to local IP address or VPN)


    1. Open Settings → Expose devices and select Add Interface. Select Modbus RTU, Modbus ASCII or Modbus TCP.
    2. Define communication properties
      • 2.1 Modbus RTU or ASCII: Terminal (BUS 1, BUS 2 or BUS 3), Baud rate, Parity, Data bits, Stop bits
      • 2.2 Modbus TCP: TCP Port. (IP Address is set specifically for every device)
    3. Add devices to be exposed
      • Each device will show brief overview how to access them in 3rd party system

    Example: Switch:

    Using Modbus TCP to connect to any other system

    Simply Modbus is a great source if you are unfamiliar with the protocol. Using open source libraries for Modbus, you can connect TapHome installation with any other system that has possibility to develop a simple driver:

    • NModbus4 - C# implementation of the Modbus protocol GitHub
    • libmodbus - A Modbus library for Linux, Mac OS X, FreeBSD, QNX and Windows GitHub
    • pymodbus - A full modbus protocol written in python GitHub
    • digitalpetri / modbus - High-performance, non-blocking, zero-buffer-copying Modbus for Java GitHub
    • goburrow / modbus - Fault-tolerant implementation of modbus protocol in Go (golang) GitHub
    • node-modbus-tcp- NodeJS Modbus TCP/IP (GitHub)

    Debugging Modbus RTU connection

    Modbus RTU is using RS485 physical layer. In order to speed up your integration, please consider parallel connection of RS485 USB converter to your PC in order to see communication.

    Standard USB to RS485 converter

    Terminal software for Windows