Standard Industrial Protocols

Modbus RTU

Modbus RTU (Remote Terminal Unit) is a commonly used data communications protocol for serial lines. Modbus may be used as a base and therefore has derivatives developed by organisations or companies (e.g. Sunspec protocol) that meet industry specific requirements.

If the machine(s) communicates via the Modbus RTU standard, or some Modbus RTU based standard protocol such, there are several setup parameters that need to be sent to the person implementing the connections.

Make sure to enable Modbus RTU for read and write on the machine(s). This can usually be done in the settings of the machine or in a web portal that communicates with the machine.

Once the machine has been connected to the Ardexa Device, and Modbus RTU has been enabled, please send the following parameters to the person implementing the connections to ensure a successful connection:

1. Machine brand and model: This allows us to understand the type of machine that is being connected. 2. Preferred name for machine: This allows us to name the data source correctly.

3. Modbus RTU type: Standard Modbus RTU, industry specific Modbus RTU, etc.

4. Serial port: Provide the serial port to which the serial line is connected.

5. Serial Address: Default value is usually 1. If different, please send to the person implementing the connections. If multiple machines are connected, they each need a unique address, and these must all be sent to the person implementing the connections.

6. Register mapping: A mapping of all the variables to their Modbus registers is required, which can often be found in the machine's manufacturing guide. In this case, the guide should be sent to the person implementing the connections.

For proprietary (non-standard) Modbus-based protocols, please also provide the following serial parameters for the machine(s):

  1. Baud rate: default value is 19200 bps, possible values are 1200-115200 bps.

  2. Databits: default value is 8, possible values are 7 or 8.

  3. Stopbits: default value is 1, possible values are 1 or 2.

  4. Parity: default value is even, possible values are none, even, odd.


If the machine communicates via CAN Bus, please consult your Ardexa Account Manager.

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