Modbus TCP/IP Menu

The Aranet Pro/Pro Plus Modbus TCP/IP feature currently supports "Input register" object types. All other types can be defined in the configuration file, but they will be ignored. It also refers to function codes. Only function code 4 is supported (read "Input register").

Aranet Pro/Pro Plus appears in the Modbus networks as a server (slave) having its own server(slave) ID. By default, the Aranet Pro/Pro Plus server (slave) ID is “1”.

Notes for the client side:

1. Register size: 16 bits
2. Endianness - big-endian with high word first

   • high byte first
   • high word first (for 2 register/32-bit values)
3. Supports only:

   • Modbus function: read input registers (code: 4)
   • Modbus data type: input registers (any address can be used in the supported range: 0 65535)
4. Used Modbus TCP exceptions

   • In case an unsupported function is requested, a reply message with "ILLEGAL_FUNCTION" code will be received.
   • In case an unavailable registry address is requested, a reply message with the "ILLEGAL_DATA_ADDRESS" code will be received. This exception is also sent in case the address conflicts with any other registry address.
   • In case an uninitialized registry address is being requested, a reply message with "ILLEGAL_DATA_VALUE" code will be received. The address of the registry exists, but valid data for measurement has not been assigned yet.

Modbus menu is where you set up the connection to the Aranet PRO/PRO Plus.

More information is available on this topic: Modbus