User`s manual

Troubleshooting Troubleshooting
MELSEC System Q, Hardware 11 – 13
11.2.11 When the USER LED has turned on
The USER LED turns on when an error is detected by the CHK instruction or the annunciator (F)
turns on. Monitor the corresponding special relays in the monitor mode of a programming device
(CHK instruction = SM80, SD80; annunciator F = SM62, SD62 to SD79).
The USER LED can be turned off by:
• Resetting with the RESET/L.CLR switch or
• Executing the LEDR instruction in the sequence program.
11.2.12 When the BAT.ARM LED has turned on
The BAT.ARM LED turns on when a low battery capacity (CPU module battery or SRAM card
battery) is detected.
Monitor the special relays and special registers (SM51, SM52, SD51 and SD52) in the monitor
mode of a programming device.
After checking, replace the battery with a new one, and reset the CPU module or run the LEDR
instruction, and the BAT.ARM LED will turn off.
11.2.13 When the BOOT LED is flickering
● When the BOOT LED of the CPU module flickers at programmable controller power-on, at
operation start, or during operation, power off the programmable controller.
● Remove the memory card.
● Move the DIP switches SW2 and SW3 of the CPU module to ON (refer to section 4.4.2).
● Power on the programmable controller.
If the BOOT LED turns on, the automatic write from memory card to standard ROM is completed.
Perform boot operation from standard ROM.
If the BOOT LED does not turn on, a hardware fault may have occurred in the CPU module.
Please consult your local Mitsubishi service center or representative, explaining a detailed
description of the problem.
NOTE When the RESET/L.CLR switch is tilted to L.CLR several times for latch clear operation, the
USER LED flickers to indicate that the latch clear processing is in process.
When the RESET/L.CLR switch is further tilted to L.CLR while the USER LED flickering, the
USER LED turns off and terminates the latch clear processing.