Read/Write Operation Examples - INVT Goodrive270 Series Operation Manual

Goodrive270 series VFD for fan and pump
Code Name
When returning a response, the slave uses a function code domain and fault address to indicate
whether it is a normal response (no error) or exception response (an error occurs). In a normal
response, the slave returns the corresponding function code and data address or sub-function code.
In an exception response, the slave returns a code that is equal to a normal code, but the first bit is
logic 1.
For example, if the master sends a request message to a slave for reading a group of function code
address data, the following code is generated:
In a normal response, the slave returns the same function code. In an exception response, the slave
returns the following code:
In addition to the modification of the code, the slave returns a byte of exception code that describes
the cause of the exception. After receiving the exception response, the typical processing of the
master is to send the request message again or modify the command based on the fault information.
For example, to set the "Channel of running commands" (P00.01, the parameter address is 0000H) to
03 for the VFD whose address is 01H, the command is as follows:
01
VFD
address
However, the "Running command channel" ranges from 0 to 2. The value 3 is out of the setting range.
In this case, the VFD returns an error message response as shown in the following:
The exception response code 86H (generated based on the highest-order bit "1" of the write
command 06H) indicates that it is an exception response to the write command (06H). The error code
is 04H, which indicates "Operation failure".

9.4.7 Read/Write operation examples

For the formats of the read and write commands, see section 9.4.1 and 9.4.2.
9.4.7.1 Read command 03H examples
Example 1: Read state word 1 of the VFD whose address is 01H. According to the table of other
Modbus function addresses in Table 9-1, the parameter address of status word 1 of the VFD is
2100H.
The read command transmitted to the VFD is as follows:
being locked" is reported.
0 0 0 0 0 0 1 1 (03H in the hexadecimal form)
1 0 0 0 0 0 1 1 (83H in the hexadecimal form)
06 00 01
Parameter
Write
address
command
01 86
VFD Exception
address response code
Definition
00 03
Parameter
data
04 43 A3
Error code CRC
-309-
Communication protocol
98 0B
CRC