Development of an algorithm for identifying an inductive speed sensor

This paper presents a new diagnostic algorithm for the early detection of faults in the data-measuring channel of inductive speed sensors used in low-speed marine internal combustion engines. Unlike traditional methods based solely on signal presence or amplitude thresholds, the proposed approach involves a two-parameter analysis combining the temporal and frequency characteristics of the sensor output signal. Specifically, the algorithm continuously monitors two key parameters: the duration of individual pulses and the number of pulses accumulated over a fixed oneminute interval. Thresholds for these parameters, set within a pulse duration range of 50 — 200 ms, are determined based on the engine speed operating range, corresponding to stable idle running and maximum load. Deviations beyond these limits trigger an alarm, indicating potential sensor degradation, electromagnetic interference, or mechanical failure. The algorithm is implemented in the CODESYS 2.3 environment using standard programmable logic controller (PLC) function blocks, ensuring compatibility with existing marine automation systems and enabling seamless integration without hardware modifications. The auxiliary simulation module simplifies autonomous validation by emulating realistic sensor signals under both nominal and fault conditions. The developed solution improves system reliability by enabling the timely detection of latent faults that are often undetectable by traditional self-diagnostic mechanisms, thereby enhancing operational safety, reducing unplanned downtime, and supporting condition-based maintenance strategies in marine environments.

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