Engee documentation

Modbus Support Blocks

Before starting to work with the library, it is recommended to read the documentation Working with Modbus TCP block library.

The library of Modbus protocol support blocks is intended for communication of the real-time application running on the RITM CPM with the control system devices via Modbus protocol.

When this library is used, the RITM, on which the real-time application is running, acts as a client of the Modbus network. Simultaneous work with 16 servers (slaves) of Modbus network is supported.

The following Modbus protocol functions are supported:

  • 1 (0x01) - reading values from several flag registers (Read Coil Status);

  • 2 (0x02) - reading values from several discrete inputs (Read Discrete Inputs);

  • 3 (0x03) - reading values from several holding registers (Read Holding Registers);

  • 4 (0x04) - reading values from several input registers (Read Input Registers);

  • 5 (0x05) - writing the value of a single flag (Force Single Coil);

  • 6 (0x06) - writing a value to a single storage register (Preset Single Register);

  • 15 (0x0F) - write values to multiple flag registers (Force Multiple Coils);

  • 16 (0x10) - writing values to multiple storage registers (Preset Multiple Registers).