BENSHAW RSi GM2 Series - Communication Protocol; Modbus-RTU Protocol

RS-485 Communication Features
890054-00-00
GM2 Series VFD
186
Note
When registering control parameters, register the operation speed (0h0005, 0h0380,
0h0381) and operation command (0h0006, 0h0382) parameters at the end of a parameter
control frame. The operation speed and operation command must be registered to the
highest number of the parameter control-h (Para Control-h).
For example, when the Para Ctrl Num is 5, register the operation speed to Para Control-4
and the operation command to Para Control-5.
Communication Protocol
The built-in RS-485 communication supports Modbus-RTU protocol.
Modbus-RTU Protocol
7.3.1.1 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).
Function Code #03: Read Holding Register
Query Field Name
Response Field Name
Station ID
Station ID
Function(0x03)
Function (0x03)
Starting Address Hi
Byte Count
Starting Address Lo
Data Hi
# of Points Hi
Data Lo
# of Points Lo
…
CRC Lo
…
CRC Hi
Data Hi
Data Lo
CRC Lo
CRC Hi
Function Code #04: Read Input Register
Query Field Name
Respo
nse
Field
Name
Response Field Name
Station ID
Station ID
Function(0x04)
Function (0x04)
Starting Address Hi
Byte Count
Starting Address Lo
Data Hi
# of Points Hi
Data Lo
# of Points Lo
…
CRC Lo
…
CRC Hi
Data Hi
Data Lo
CRC Lo
CRC Hi
# Number of Points
# Number of Points