Goodrive3000 series medium voltage VFD
Moudbus protocol
-205-
Code
Name
Meaning
06H
Incorrect data
frame
The data frame sent from the host controller is incorrect in the length, or in the
RTU format, the value of the CRC check bit is inconsistent with the CRC value
calculated by the lower computer.
07H
Parameter
read-only
The parameter to be modified in the write operation of the host controller is a
read-only parameter.
08H
Parameter can
be modified in
running
The parameter to be modified in the write operation of the host controller cannot
be modified during the running of the VFD.
09H
Password
protection
If the host controller does not provide the correct password to unlock the system
to perform a read or write operation, the error of “system being locked” is
reported.
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:
0 0 0 0 0 0 1 1 (03H in the hexadecimal form)
In a normal response, the slave returns the same function code. In an exception response, the slave returns:
1 0 0 0 0 0 1 1 (83H in the hexadecimal form)
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 "Running command channel" (P00.01, the parameter address is 0001H) of the VFD whose
address is 01H to 03, run the following command:
VFD
address
Write
command
Parameter
address
Parameter
data
CRC
01
06
00 01
00 03
98 0B
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:
VFD
address
CRC
Error code
Exception
response code
01
86
04
43 A3
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".
8.4.7 Reading and writing examples
For the formats of the read and write commands, see sections 8.4.1 and 8.4.2.
8.4.7.1 Example of reading command 03H
Example 1: Read state word 1 of the VFD whose address is 01H. According to the table of other Modbus function
addresses, the parameter address of state word 1 of the VFD is 2100H.
The read command transmitted to the VFD is as follows:
