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MELSEC-A
6 TROUBLESHOOTING
6.2 Using the LED Indications to Check Errors
This section explains how to check errors using the LED indications of the AJ65SBT-
64AD.
Refer to the PLC CPU and master module user's manual for issues regarding the PLC
CPU and master module.
(1) When the AJ65SBT-64AD "PW" LED is off
Check item Corrective action
Is 24VDC power on? Check the external power supply.
Is the voltage of the 24VDC power supply within the
specified value?
Set the voltage value to within the range 20.4 to
26.4V.
(2) When the AJ65SBT-64AD "RUN" LED is flashing
Check item Corrective action
Is the LED flickering at 0.1s intervals in the normal
mode?
1. Using the remote input signals (RXn4 to RXn7),
check the channel at which the input range
setting error has occurred.
2. Make correction to the sequence program or
GPPW setting.
Is the LED flickering at 0.1s intervals in the test
mode?
Set all channels to any of "user range settings 1 to
3" in input range setting.
Is the LED flickering at 0.5s intervals in the test
mode?
Change the offset/gain adjustment to within the
available setting range.
(3) When the AJ65SBT-64AD "RUN" LED is off
Check item Corrective action
Has the watchdog timer error occurred?
Using the link special registers (SW0084 to
SW0087) of the master module, check the
watchdog timer error and power on the AJ65SBT-
64AD again.
If the "RUN" LED is not lit after power is switched
on again, the possible cause is a hardware fault.
Contact your nearest Mitsubishi representative.
Has the TEST terminals (across 8-9) been shorted
to enter the test mode?
After making offset/gain adjustment, open the TEST
terminals (across 8-9).
(4) When the AJ65SBT-64AD "L RUN" LED is off
Communications are broken.
For details, refer to troubleshooting in the user's manual of the master module
used.