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Chapter 4 Parameters|
Revision Nov. 2008, VLE1, SW V1.03 4-95
3.6 Exception response:
The AC motor drive is expected to return a normal response after receiving command messages
from the master device. The following depicts the conditions when no normal response is replied to
the master device.
The AC motor drive does not receive the messages due to a communication error; thus, the AC
motor drive has no response. The master device will eventually process a timeout condition.
The AC motor drive receives the messages without a communication error, but cannot handle them.
An exception response will be returned to the master device and an error message “CExx” will be
displayed on the keypad of AC motor drive. The xx of “CExx” is a decimal code equal to the
exception code that is described below.
In the exception response, the most significant bit of the original command code is set to 1, and an
exception code which explains the condition that caused the exception is returned.
Example of an exception response of command code 06H and exception code 02H:
ASCII mode: RTU mode:
STX ‘:’ Address 01H
‘0’ Function 86H Address Low
Address High
‘1’ Exception code 02H
‘8’ CRC CHK Low C3H Function Low
Function High
‘6’ CRC CHK High A1H
‘0’
Exception code
‘2’
‘7’ LRC CHK Low
LRC CHK High
‘7’
CR END 1
END 0
LF
The explanation of exception codes:
Exception
code
Explanation
01
Illegal function code:
The function code received in the command message is not
available for the AC motor drive.
02
Illegal data address:
The data address received in the command message is not
available for the AC motor drive.
03
Illegal data value:
The data value received in the command message is not available
for the AC drive.
04
Slave device failure:
The AC motor drive is unable to perform the requested action.
10
Communication time-out:
If Pr.09-03 is not equal to 0.0, Pr.09-02=0~1, and there is no
communication on the bus during the Time Out detection period (set
by Pr.09-03), “cE10” will be shown on the keypad.