Checking With Leds - Mitsubishi Electric MELSEC iQ-F FX5 User Manual

Checking with LEDs

Check the module status with LEDs as a means to perform the primary diagnosis.
Each LED status can be checked by using the Module diagnostics (CPU Diagnostics) of the engineering tool.
(GX Works3 Operating Manual)
Checking the PWR LED
If the PWR LED is turned off, check the following items.
Item to check
Measure the voltage input to the CPU module.
Remove extension modules and all wiring other than the
one for the power supply, and turn on the power supply.
If the PWR LED still does not turn on even after the items shown above are checked, there may be a hardware issue.
Consult your local Mitsubishi Electric representative.
Checking the BAT LED
If the BAT LED is flashing, check the following items.
The LED is valid when the optional battery is installed and the LED is set to "display" for battery errors by using the parameter.
Item to check
Check the installation of the battery.
Check the battery voltage.
Checking the ERR LED
If the ERR LED flashing, check the following items.
Item to check
Write system parameters, CPU parameters, and program
files, and turn on the power supply again.
If the ERR LED is turned on, check the following items.
Item to check
Set the CPU module to the STOP status and turn on
the power supply again.
Provide a different power supply to the CPU module.
If the ERR LED still does not turn off even after the items shown above are checked, there may be a hardware issue.
Consult your local Mitsubishi Electric representative.
Checking the P.RUN LED
If the P.RUN LED is turned off, check the status of the ERR LED and take corrective actions. (Page 41 Checking the ERR
LED)
Cause and action
If the power source is not supplying the proper voltage, provide a power source that does.
If the PWR LED turns on in this condition, the 24 V DC service power supply may be shorted or
overloaded. Reconnect the modules and wire one by one to identify the cause.
Cause and action
Install the battery properly.
If the battery voltage is reduced, replace the battery with a new one.
Battery voltage can be monitored with PLC data register SD8005.
(MELSEC iQ-F FX5U User's Manual (Hardware))
(MELSEC iQ-F FX5UC User's Manual (Hardware))
Cause and action
Programs or parameters may not written or damaged. Since a CPU module with the factory
default setting has no programs, the ERR LED flashes.
Cause and action
When the ERR LED turns off, a watchdog timer error has probably occurred. Take any of the following
measures.
• Review the program and avoid the maximum value (SD524, SD525) of the scan time exceeding the
scan time monitoring time setting value set by the parameter.
• Check that the input used for input interruption or pulse catch is not being abnormally turned on and
off in one scan.
• Check that the frequency of the pulse input to the high-speed counter is within the specified range.
• Add some WDT instructions to the program and reset the watchdog timer several times in one scan.
If the ERR LED turns off, noise may have affected the module. Consider taking the following measures.
• Check the ground wiring, and reexamine the wiring route and installation location.
• Fit a noise filter onto the power supply line.
4 PROCEDURES BEFORE OPERATION
4.14 Troubleshooting
4
41