TECHTOP TD20 Series Product Manual page 111

TD20 Series VFD
Code Name
04H Operation failed
05H Password error
06H Data frame error
Written not
07H
allowed.
The parameter
cannot be
08H
modified during
running
Password
09H
protection
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" of the VFD (P00.01, parameter address is 0001H) with
the address of 01H to 03, the command is as following:
VFD
address
But the setting range of "running command channel" is 0–2, if it is set to 3, because the number is
exceed the range, but indicate the message frame is an illegal
frame.
The parameter setting in parameter writing is invalid. For example,
the function input terminal cannot be set repeatedly.
The password written to the password check address is not same
as the password set by P7.00.
In the frame message sent by the upper monitor, the length of the
digital frame is incorrect or the counting of CRC check bit in RTU is
different from the lower monitor.
It only happen in write command, the reason maybe:
1. The written data exceeds the parameter range.
2. The parameter should not be modified now.
3. The terminal has already been used.
The modified parameter in the writing of the upper monitor cannot
be modified during running.
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.
Parameters
Read
command address
Meaning
Parameters
data
-109-
Communication Protocol
CRC check