| Symptom | Likely Cause | Fix | | :--- | :--- | :--- | | | Incompatible or unseated sensor | Power down, reseat sensor, ensure firmware matches sensor type. | | 4-20mA reads 0mA (open circuit) | Wiring polarity reversed on OUT1 | Swap the signal and ground wires on the PLC side. | | Reading drifts after warm-up | Moisture or debris on sensor | Remove sensor, dry with warm (not hot) air for 2 hours, reinstall. |