The spindle sensor is a vibration‑monitoring module that interfaces with the machine tool’s control system to provide real‑time displacement and vibration data for predictive maintenance. Common failure modes include loss of signal due to wiring corrosion, sensor misalignment causing false high‑amplitude readings, or firmware corruption leading to erratic outputs; sensors may also fail mechanically if bearings wear out or heat exceeds design limits. First‑check diagnostics: verify power and ground continuity to the sensor board, inspect cable harness for fraying or loose connectors, and review the host controller’s error logs for communication timeouts or abnormal vibration thresholds.[oss-gpt-20b]