Message functions – Yaskawa GPD 515-G5 Modbus RTU User Manual
Page 22
6-2 The Message Format
Message Functions
In communicating to the GPD 515 drive via Modbus RTU, there are three message functions
available. The master specifies the function to be executed by the slave according to the function
code. The following table shows the types of function codes available, and the length (quantity)
and contents of the message according to the function.
Function
Code (hex)
Function
Command
Message
Response
Message (Normal)
min.
(bytes)
max.
(bytes)
min.
(bytes)
max.
(bytes)
3
Read Multiple Registers
8
8
7
37
8
Loop-back test
8
8
8
8
10
Write Multiple Registers
11
41
8
8
The message format varies depending upon the function of the message. For each function,
there is a command message from the master and a response message initiated from the slave.
The following sections review the format of the command message and the response message
for each function.