of the VFD (E00.01,
Communication Protocol
144
Code
Name
Meaning
09H
Password
protection
When the upper monitor is writing or reading and the user password is
set without password unlocking, it will report that the system is locked.
The slave uses functional code fields and fault addresses to indicate it is a normal response or
some error occurs (named as objection response). For normal responses, the slave shows
corresponding function codes, digital address or sub-function codes as the response. For objection
responses, the slave returns a code which equals the normal code, but the first byte is logic 1.
For example: when the master sends a message to the slave, requiring it to read a group of
address data of the VFD function codes, there will be following function codes:
0 0 0 0 0 0 1 1 (Hex 03H)
For normal responses, the slave responds the same codes, while for objection responses, it will
return:
1 0 0 0 0 0 1 1 (Hex 83H)
Besides the function codes modification for the objection fault, the slave will respond a byte of
abnormal code which defines the error reason.
When the master receives the response for the objection, in a typical processing, it will send the
message again or modify the corresponding order.
For example, set the "running command channel"
parameter address is
0001H) with the address of 01H to 03, the command is as following:
VFD
address
Read
command
Parameters
address
Parameters
data
CRC check
But the setting range of "running command channel" is 0
–
2, if it is set to 3, because the number is
beyond the range, the VFD will return fault response message as below:
VFD
address
CRC check
Fault code
Abnormal
response code
Abnormal response code 86H means the abnormal response to writing command 06H; the fault
code is 04H. In the table above, its name is operation failed and its meaning is that the parameter
setting in parameter writing is invalid. For example, the function input terminal cannot be set
repeatedly.
9.6 Example of writing and reading
Refer to 9.4.1 and 9.4.2 for the command format.
9.6.1 Example of reading command 03H
Read the state word 1 of the VFD with the address of 01H (refer to table 1). From the table 1, the
parameter address of the state word 1 of the VFD is 2100H.