Mitsubishi Electric MELSEC iQ-F FX5UC Series, User Manual

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15 TROUBLESHOOTING
15.7 Troubleshooting for Each Symptom
261
15
Input does not turn off
Writing/reading data
Data cannot be written to the programmable controller
If data cannot be written to the CPU module from the engineering tool, check the following items.
If writing still cannot be performed even after the items shown above are checked, there may be a hardware issue. Consult
your local Mitsubishi Electric representative.
Data cannot be read from the programmable controller
If data cannot be read from the CPU module to the engineering tool, check the specification of the target memory to be read.
Check the memory and reset the CPU module again. Then try programmable controller read again.
If reading still cannot be performed, there may be a hardware issue. Consult your local Mitsubishi Electric representative.
The program is unintentionally overwritten
The boot operation may be being performed. Read the parameters and review the boot file settings with the engineering tool.
If the boot operation is not being performed, there may be a hardware issue. Consult your local Mitsubishi Electric
representative.
For details on the boot operation, refer to

MELSEC iQ-F FX5 User's Manual (Application).
■ For the FX5UC-  M  /DS 
Disconnect the external wiring and apply a voltage of 24VDC "between the
COM
 terminal and the input terminal" or "between the S/S terminal and the
input terminal". Check with the LED or a peripheral whether the input turns on.
■ When the input turns on
Check that the input device does not have a built-in diode or parallel
resistance. If so, refer to the precautions for connecting input devices.
■
When the input does not turn on
With a tester, check that the voltage "between the COM  terminal and the
input terminal" or "between the S/S terminal and the input terminal" is
approximately 24VDC.
When the input voltage is below 20.4VDC, check that the voltage of the
external power supply is "24VDC +20%, -15%".
Check the configuration of the external wiring and connected devices and the
connection of the extension cables.
Item to check Action
Check that there is no leakage current from input devices. When the leakage current is 1.5mA or more, connect a bleeder resistance.
(
 Page 178 Wiring precautions)
Item to check Action
Check if a password is not registered. When a password has been registered, authenticate the password with the
engineering tool.
When an SD memory card is the write destination, check that the write
protection is not applied to the card. Remove the write protection from the SD memory card.
 Page 81 SD Memory Card
When an SD memory card is the write destination, check that the card is
formatted. Format the SD memory card.
Check that the size of the write data does not exceed the memory capacity. • Ensure sufficient empty capacity.
• After initializing the memory, write in the set of project data backed up by the
customer.
Item to check Action