Frequency Inverter ST600 Series High-Performance Multifunction VFD Communication protocol
-293-
For the VFD, the data address in the request of the controlling computer is not
allowed. In particular, the combination of the register address and the number of
the to-be-transmitted bytes is invalid.
The received data domain contains a value that is not allowed. The value
indicates the error of the remaining structure in the combined request.
Note: It does not mean that the data item submitted for storage in the register
includes a value unexpected by the program.
The parameter is set to an invalid value in the write operation. For example, a
function input terminal cannot be set repeatedly.
The password entered in the password verification address is different from that
set in P07.00.
The length of the data frame transmitted by the controlling computer is incorrect,
or in the RTU format, the value of the CRC check bit is inconsistent with the CRC
value calculated by the lower computer
The parameter to be modified in the write operation of the controlling computer is
a read-only parameter.
Parameter
cannot be
modified in
running
The parameter to be modified in the write operation of the controlling computer
cannot be modified during the running of the VFD.
A user password is set, and the controlling computer does not provide the
password to unlock the system when performing a read or write operation. The
error of "system locked" is reported.
When returning a response, the device uses a function code domain and fault address to indicate
whether it is a normal response (no error) or exception response (some errors occur). In a normal
response, the device returns the corresponding function code and data address or sub-function code.
In an exception response, the device returns a code that is equal to a normal code, but the first bit is
logic 1.
For example, if the master device transmits a request message to a slave device for reading a group
of function code address data, the code is generated as follows:
0 0 0 0 0 0 1 1 (03H in the hexadecimal form)
For a normal response, the same code is returned.
For an exception response, the following code is returned:
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
device is to transmit 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, the command is as follows:
To Next Page
Loading...
