11
 TROUBLESHOOTING
11.1 Troubleshooting
11 - 8
9
PROGRAMMING
10
DEDICATED 
INSTRUCTIONS
11
TROUBLESHOOTINGAPPENDICESINDEX
(Continued on next page)
Table11.3 Troubleshooting for other symptoms (Continued)
No. Symptom Check point Corrective action Reference
5
The diagnostic counter 
has counted up.
Master/
Slave
Bus communication error 
count
Check the Error log (address: 0CFE
H
 to 
0DFF
H
) in the buffer memory and take 
corrective actions for the error code.
Section 11.4.1
Character overrun error count
Refer to the corrective actions for the 
character overrun error (error code: 
7399
H)
Section 11.3
Section 11.4.3
Data discard count
• If it is caused by connecting the module 
to the online network, powering it on 
and accessing the network, do not 
perform such kind of operation. No 
specific action is necessary if there is no 
problem.
• If it is caused by turning off, resetting or 
disconnecting the device in 
transmission from the line, reset, do not 
perform such kind of operation during 
transmission. No specific action is 
necessary if there is no problem.
• If the message is erroneous, refer to 
"Communication with the target device 
is not available even if parameter setting 
has been completed normally.".
This section 
(3)-7
Failed transmission count
Refer to the corrective actions for the CS 
signal OFF error (error code: 7403
H)
Section 11.4.3
6
An error is found in the 
communications event 
log.
Communication error occurred.
Check the Error log (address: 0CFE
H
 to 
0DFF
H
) in the buffer memory and take 
corrective actions for the error code.
Section 11.4.1
Character overrun error occurred.
Refer to the corrective actions for the 
character overrun error (error code: 
7399
H)
Section 11.4.3
Message error occurred. Check the Error log (address: 0CFE
H
 to 
0DFF
H
) in the buffer memory and take 
corrective actions for the error code.
Section 11.4.1
Processing interrupt occurred.
7
Communication with the 
target device is not 
available even if 
parameter setting has 
been completed normally.
Is the station number setting correct?
If there is a problem with the setting, 
correct the intelligent function module 
switch setting and reset the module.
Section 6.6
Check if the transmission settings of the 
QJ71MB91 are consistent with those of 
the target device.
Check the settings again and if there is a 
problem with the setting, correct the 
intelligent function module switch setting 
and reset the module.
Section 6.6
Is the frame mode setting (RTU mode/
ASCII mode) correct?
If there is a problem with the setting, 
correct the intelligent function module 
switch setting and reset the module.
Section 6.6