Err Led; Led; Troubleshooting Using The Engineering Tool - Mitsubishi Electric MELSEC iQ-F Series User Manual

Checking the ERR LED
If the ERR LED flashes
If the ERR LED flashes, 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 turns on
If the ERR LED turns 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 turns off, noise may have affected the module. Consider taking the following measures.
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 102 Checking the

ERR LED)

9.3

Troubleshooting using the engineering tool

Check the error or history using the engineering tool, and identify the error cause. More detailed information on the error
as well as the error cause and action to be taken can be checked by using the engineering tool.
The engineering tool has the following functions for troubleshooting.
Function
Module Diagnostics (CPU Diagnostics)
For details on each function, refer to the
following. GX Works3 Operating Manual
102
9 TROUBLESHOOTING
9.3 Troubleshooting using the engineering tool
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
setting value of the scan time monitoring time which was set with parameters.
• 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.
• Check the ground wiring, and reexamine the wiring route and installation location.
• Fit a noise filter onto the power supply line.
Description
This function diagnoses the module. (The current error and its details can be checked.)