8 TROUBLESHOOTING
MELSEC-Q
     8 - 128    8 - 128
*1 : Characters in parentheses ( ) indicate the special register numbers where individual information is being 
stored.
Error 
Code
(SD0)
*1
Error Contents and Cause Corrective Action
Corresponding 
CPU
5000
• The scan time of the initial execution 
type program exceeded the initial 
execution watch time specified in 
the PLC RAS setting of the PLC 
parameter dialog box.
• Standby system power-off occurred.
• The tracking cable was 
disconnected and reinserted without 
the standby system being powered 
off or reset.
• The tracking cable is not secured by 
the connector fixing screws.
• Read the individual information of 
the error with the peripheral device, 
check its value (time), and shorten 
the scan time. 
• Change the initial execution watch 
time or the WDT value in the PLC 
RAS setting of the PLC parameter 
dialog box.
• Resolve the endless loop caused by 
jump transition.
• Since power-off of the standby 
system increases the control system 
scan time, re-set the WDT value, 
taking the increase of the control 
system scan time into consideration.
• When the tracking cable is 
disconnected during operation, 
securely connect it and restart. If the 
same error is displayed again, the 
cause is the hardware fault of the 
tracking cable or CPU module. 
(Contact your local Mitsubishi 
representative, explaining a detailed 
description of the problem.)
QnA
Qn(H)
QnPH
QnPRH
5001
• The program scan time exceeded 
the WDT value specified in the PLC 
RAS setting of the PLC parameter 
dialog box.
• Standby system power-off occurred.
• The tracking cable was 
disconnected and reinserted without 
the standby system being powered 
off or reset.
• The tracking cable is not secured by 
the connector fixing screws.
5010
• The program scan time exceeded 
the constant scan time specified in 
the PLC RAS setting of the PLC 
parameter dialog box.
• The low speed program execution 
time specified in the PLC RAS 
setting of the PLC parameter dialog 
box exceeded the excess time of the 
constant scan.
• Review the constant scan setting 
time.
• Review the constant scan time and 
low speed program execution time 
in the PLC parameter so that the 
margin time of constant scan may 
be fully reserved.
QnA
Qn(H)
QnPH
QnPRH
The program scan time exceeded the 
constant scan time specified in the 
PLC RAS setting of the PLC 
parameter dialog box.
• Review the constant scan time in the 
PLC parameter so that the margin 
time of constant scan may be fully 
reserved.
Q00J/Q00/Q01
5011
The scan time of the low speed 
execution type program exceeded the 
low speed execution watch time 
specified in the PLC RAS setting of the 
PLC parameter dialog box.
Read the individual information of the 
error using the peripheral device, 
check the numerical value (time) there, 
and shorten scan time if necessary. 
Change the low speed execution 
watch time in the PLC RAS setting of 
the PLC parameter dialog box.
QnA
Qn(H)
QnPH