7.3.2 Modbus-RTU Protocol
7.3.2.1 Function Code and Protocol (Unit: byte)
In the following section, station ID is the value set at CM.01 (Int485 St ID), and
starting address is the communication address. (The starting address size is in bytes).
For more information about communication addresses, refer to 7.4 DriveView9 on
page 226.
Function Code #03: Read Holding Register
Function Code #04: Read Input Register