Mitsubishi Electric · MELSEC iQ-R I/O Module
The I/O status indicator LED for a specific input point is not illuminated, suggesting that the external input signal is either not present, not strong enough, or not being processed correctly by the I/O module. This can be due to a missing or incorrect external power supply to the I/O module or an internal module failure.
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Verify that the external power supply for the I/O module is connected and that its voltage meets the module's specifications.
Use the engineering tool to perform a forced ON/OFF operation on the device concerned and observe if the I/O indicator LED responds accordingly.
If the I/O indicator LED error persists after troubleshooting, consult your local Mitsubishi Electric representative.