1. Zero-point drift anomaly
Symptom: Output current deviates from the 4mA baseline value under no load (deviation > ±0.2mA).
Reason: Deformation of the sealing ring (silicone ring expansion rate > 5% at high temperatures) or tilted installation (angle > 5°) leading to abnormal stress transmission.
Solution: Replace with a fluororubber sealing ring (temperature resistance > 200℃), and use a laser level to calibrate the mounting surface (angle deviation < 0.5°).
2. Electromagnetic interference
Symptom: Calibration signal superimposed with 50/100Hz power frequency noise (fluctuation > ±0.5mA).
Reason: Signal lines are laid parallel to frequency converter cables (spacing < 20cm) or shielding layer grounding failure (grounding resistance > 4Ω).
Solution: Run signal lines through galvanized steel pipes (wall thickness ≥ 1.2mm) with double-ended grounding, and add a copper shielding cover (attenuation ≥ 30dB).
3. Installation stress interference
Symptom: Sensitivity decreases by 20%-30%, linearity < 85%.
Reason: Uneven bolt torque (deviation > ±2N·m) or insufficient base flatness (roughness Ra > 3.2μm).
Solution: Gradually increase torque in steps (6N·m→9N·m→12N·m), and grind the mounting surface to Ra ≤ 1.6μm.
4. Temperature drift exceeding limits
Symptom: Zero-point offset > 0.5%FS for every 10℃ increase in temperature.
Reason: Charge output type sensor not selected in high-temperature environment (>80℃) or PCB compensation circuit failure.
Solution: Switch to a charge output model with a temperature resistance of 150℃ (such as the ST5484E-121 series), and regularly check the thermistor resistance value (should be 10kΩ±1% at 25℃). 5. Electrostatic Discharge Damage
Symptoms: Wheatstone bridge open circuit, output signal drops to zero.
Cause: Electrostatic discharge from the human body (>5000V) breaks down the sensing element.
Solution: Wear an anti-static wrist strap (grounding resistance 1MΩ) before operation, and select a Class 3B protection level sensor (ESD resistance ≥8000V).
6. Calibration Equipment Error
Symptoms: Non-linear error still >2% after multiple calibrations.
Cause: Using an uncertified vibration table (accuracy <±1%) or neglecting high-frequency ranges (e.g., >10kHz).
Solution: Use a certified vibration table (accuracy ±0.5%), covering the full frequency range for calibration.
