The Modbus protocol performs serial communication between the master and subordinate (VFD) using the dedicated message frame. The dedicated message frame has functions that can read and write data. Using these functions, you can:
- read and write the parameter values from the VFD
- write the input commend of the VFD
- check the operating status
The master communicates with the subordinate (VFD) by accessing the assigned holding register address.
Note: There are two different serial transmission modes: ASCII (American
Standard Code for Information Interchange) and RTU (Remote Terminal Unit) mode. This
product supports only the RTU mode, in which 1-byte (8-bit) data is transmitted as it
is. Only the communication protocol is defined by the Modbus protocol - the physical
layer is not stipulated.