When The Alm Led Turns On Or Flashes; When Watchdog Timer Error Flag (Xn0) Is On; When Error Flag (Xn2) Is On - Mitsubishi Electric MELSEC-Q Series User Manual

8 TROUBLESHOOTING

8.5 When the ALM LED Turns On or Flashes

8.6 When Watchdog Timer Error Flag (Xn0) Is On

8.7 When Error Flag (Xn2) Is On

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(1) When the LED turns on
Check item
Has Alert flag (XnC and XnD) turned on?
(2) When the LED flashes
Check item
Is the process value beyond the measured
range specified for the input range?
Is there any channel where a sensor is not
connected?
Has a loop disconnection been detected?
Check item
Check item
Has a write data error occurred?
Has AT error completion occurred?
Has a hardware error occurred?
Action
Check the contents of Alert definition (buffer
memory address: 5, 6) and take action for it.
Action
Change the input range setting to the
operating ambient range setting.
Set the channels, where the sensors are
disconnected, to unused at Unused channel
setting (buffer memory address: 61, 93).
Check for a load disconnection, external
operation device failure, sensor disconnection.
Action
Reset the programmable controller CPU or
turn on the power supply module again.
If the watchdog timer error turned on again, it
represents the Q62HLC hardware failure.
Please consult your local Mitsubishi
representative.
Action
Check the error code list in Section 8.1 and
correct the sequence program.
Check the error code list in Section 8.1 and
correct the sequence program.
• When cold junction temperature
compensation resistor is disconnected,
connect it.
• It represents the Q62HLC hardware failure.
Please consult your local Mitsubishi
representative.
MELSEC-Q
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