Mitsubishi QJ71MB91, User Manual

Page: 333 / 372

11
TROUBLESHOOTING
11.4 Error Codes
11.4.2 Exception code list
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11.4.2 Exception code list
"Exception code" is an error code common to the MODBUS protocol, which is
embedded in a response message when a slave returns an error response in reply to a
request message sent from the master.
(1) When the QJ71MB91 is a master
When the QJ71MB91 (master) has received an exception code from the target device
(slave), take corrective actions referring to the manual for the target device (slave).
(2) When the QJ71MB91 is a slave
When the target device (master) has received an exception code from the QJ71MB91
(slave), take corrective actions referring to the following.
(a) Exception code storage location
When processing on a slave (QJ71MB91) has completed in error, the exception
code can be confirmed by the Error log area (address: 0CFE
H
to 0DFF
H
) in the
buffer memory.
(b) Exception code list
The following is a list of exception codes used when the QJ71MB91 is a slave
(Continued on next page)
Table11.15 Exception code list
Exception
code
Error name Description
Corrective action
Target device (Master side) QJ71MB91 (Slave side)
01
H
(1)
Illegal Function
The slave (QJ71MB91) received
an unsupported function code.
Check function codes supported
by the QJ71MB91, and modify the
request message to be sent.
-
02
H
(2)
Illegal Data
Address
The specified address of the
MODBUS device is erroneous.
Check the MODBUS device
type and size supported by the
QJ71MB91, and correct the
specified address in the request
message to be sent.
-
03
H
(3)
Illegal Data Value
A value contained in the data unit
of the request message is
incorrect.
Review the data unit of the
request message.
-
04
H
(4)
Slave Device
Failure
An unrecoverable error occurred
while the slave (QJ71MB91) was
attempting to perform the
requested action.
Review the data unit of the
request message.
Remove the cause of the error
occurred on the QJ71MB91 side.
If the QJ71MB91 issued this code,
check the error code in the Error
log area and take corrective
actions.
( Section 11.4.1 (8))