Knowledge Base /
Technical Notes
MODBUS TCP/IP Functions Supported
By Martin Berutti
Product: IOD-4101 - Modbus TCP/IP Master Driver (General Modbus TCP/IP Communications)

This technical note answers questions about what Modbus functions are supported by the DeltaV Virtual IO Module.

The DeltaV Virtual IO Module, VIM-4201, with the Modbus TCP/IP Driver, IOD-4101, supports the following Open Modbus TCP/IP functions:

Class 0 -

  • Read Multiple Registers (3)
  • Write Multiple Registers (16)

Class 1 -

  • Read Coils (1)
  • Read Input Discretes(2)
  • Read Input Registers (4)
  • Write Coil (5)
  • Write Single Register (6)

Class 2 -

  • Force Multiple Coils (15)

Machine/vendor/network specific functions -

  • Diagnostics(8)

Other unsupported functions don't really fit into the DeltaV serial dataset architecture, are PLC specific, or have historically been deemed unnecessary.