How to Determine if a Temperature Averaging Sensor Needs Replacement

Determining whether a temperature averaging sensor needs replacement requires a comprehensive assessment based on three dimensions: data anomalies, physical detection, and system response. Especially in Wuhan's high-temperature and high-humidity environment, a combination of AI early warning systems and on-site tools is crucial for accurate decision-making.

1. Data Anomalies: Distorted System Readings (Primary Signal)

Continuous Exceeding of Main/Backup Temperature Difference: If the difference between the main and backup sensor readings at the same location exceeds 2°C for 3 consecutive seconds and cannot be recovered after nitrogen purging, it indicates that the main sensor has drifted or failed.

Temperature Jump or Zeroing: If a temperature jump exceeds 5°C/s or the signal remains zero for more than 10 seconds outside of start-up/shutdown phases, it may indicate a broken wire, short circuit, or insulation breakdown.

Automatic AI Health Weight Reduction: If the PHM system shows that the weight of this location has been reduced to <0.3, while other locations are normal, it indicates low data reliability.

2. Physical Inspection: Abnormal Circuit Condition (On-site Verification)

Multimeter Resistance Measurement: Thermocouple circuit resistance should be 2~10Ω. <2Ω indicates a short circuit, >10Ω indicates poor contact or an open circuit.

Insulation Resistance Test: Use a 500VDC megohmmeter to measure the insulation resistance between the casing and the signal line. It should be >100MΩ. A value below this indicates moisture or damage.

Infrared Thermometer Comparison: If the measured temperature on the nozzle's outer surface deviates from the system reading by >3℃, and coking is ruled out, the temperature measurement is inaccurate.

Operational Recommendation: Perform a rapid comparison during each shift's inspection to form a "data-physical" dual verification closed loop.

3. System Functionality Test: Fault Tolerance Mechanism Failure

Redundancy Switching Failure: Simulating a main sensor disconnection, the system fails to switch to the backup channel within 0.5 seconds, or the temperature fluctuation after switching exceeds ±1.0℃;

Ineffective Filtering: Injected noise signals cause the controller's 5Hz low-pass filter to fail to suppress glitches, resulting in incorrect AI compensation;

Safety Degradation Anomaly: After disconnecting AI communication, the system cannot seamlessly switch to PID control, leading to excessive temperature control accuracy.

Engineering Standard: Failure of any of the three tests indicates a potential problem with the sensor or circuit, requiring replacement.

4. Common Replacement Trigger Scenarios (Wuhan High Humidity Focus)