Mitsubishi Electric · MELSEC iQ-R I/O Module
A leakage current from a limit switch with an integrated neon lamp prevents the input signal from turning off. The characteristics of the neon lamp allow sufficient current to flow, keeping the input module's terminals above the OFF voltage threshold, which results in a false ON state.
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Connect an appropriate resistor in parallel across the input terminals to reduce the voltage below the OFF threshold (same as INPUT-LKG-C1).
Configure the input circuit to be independent and provide a separate display circuit to avoid unintended signals affecting the primary input.