Judging the quality of a sensor requires a comprehensive evaluation from three aspects: performance indicators, measurement methods, and environmental adaptability, to ensure accurate data and stable operation in practical applications.
Judging Quality by Core Performance Indicators
The intrinsic quality of a sensor can be measured by the following key indicators:
Accuracy: The degree to which the measured value closely approximates the true value; the smaller the error, the better.
Sensitivity: The ability of the output signal to respond to changes in the input; high sensitivity can capture minute changes.
Linearity: The degree to which the input-output relationship deviates from an ideal straight line; the smaller the value, the more stable the characteristics.
Repeatability: The consistency of results when measuring the same quantity multiple times; directly affects reliability.
Stability: Minimal performance drift after long-term operation; not easily affected by factors such as time and temperature.
Response Time: Quickly reflects changes in the measured parameter; suitable for dynamic monitoring scenarios.
High-quality sensors typically provide complete calibration data and error range specifications at the factory.
Commonly Used Measurement Methods for Testing Sensor Performance
1. Multimeter Testing (Basic Method): Measure whether the sensor's input/output resistance is within the nominal range.
For example, the bridge resistance of a weighing sensor should be 380±2Ω, and the signal terminal resistance should be 350Ω±10Ω.
Temperature sensors can have their resistance measured at different temperatures to observe whether they conform to the expected trend.
2. Voltage/Current Signal Testing: After powering the sensor, check whether its output signal is normal.
For example, the resistance of a water temperature sensor at 80℃ should be between 200–400Ω; deviation may indicate damage.
When an oxygen sensor is working normally, its voltage should fluctuate between 0.1–0.9V; a fixed high or low level indicates failure.
3. Oscilloscope Waveform Analysis (Advanced Diagnosis): Observe the dynamic signal waveform; for example, the crankshaft position sensor output should be regular pulses.
Waveform distortion, abnormal amplitude, or no signal indicates a sensor or circuit fault.