Troubleshooting
When the system has any trouble, perform troubleshooting in the following order.
1.
Check that each module is properly mounted and wired.
2.
Check the LED status of the CPU module.
3.
Check the LED status of each intelligent function module. (User's manuals for each module)
4.
Connects the engineering tool and execute the Module diagnostics(CPU Diagnostics) function. The error cause and the
action to be taken can be displayed.
5.
If the error cause cannot be identified in steps 1 to 3, troubleshoot by symptom. (User's manuals for each module)
Checking with LEDs
Check the module status with LEDs as a means to perform the primary diagnosis.
Checking the PWR LED
If the PWR LED is turned off, check the following items.
If the BAT LED is turned on, 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.
Checking the ERR LED
If the ERR LED flashes, check the following items.
If the ERR LED is turned on, check the following items.
If the ERR LED still does not turn off, there may be a hardware issue.
Consult your local Mitsubishi Electric representative.
If the P.RUN LED is turned off, check the status of the ERR LED and take corrective actions.
Item to check
Cause and action
Measure the voltage input to the CPU module.
If the power source is not supplying the proper voltage, provide a power source that does.
Remove extension modules and all wiring other than the
one for the power supply, and turn on the power supply.
If the PWR LED turns on in this condition, the service power supply may be shorted or
overloaded. Reconnect the modules and wire one by one to identify the cause.
Item to check
Cause and action
Check the installation of the battery.
Install the battery properly.
Check the battery voltage.
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))
Item to check
Cause and action
Write system parameters, CPU parameters, and program
files, and turn on the power supply again.
Programs or parameters may not written or damaged. Since a CPU module with the factory
default setting has no programs, the ERR LED flashes.
Item to check
Cause and action
Set the CPU module to the STOP status and turn on
the power supply again.
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.
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.
• Check the ground wiring, and reexamine the wiring route and installation location.
• Fit a noise filter onto the power supply line.
If the PWR LED still does not turn on, there may be a hardware issue.
C
onsult your local Mitsubishi Electric representative.
Checking the BAT LED
Checking the P.RUN LED
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Summary of Contents for FX5U Series
Page 1: ...FX5U Training Manual ...
