Shanghai Beizhi Electronic Technology Co., Ltd/Shanghai Biaozhi Electronic Technology Co., Ltd.

I. Incorrect Bias Voltage

1. Bias voltage equals the supply voltage

   • Cause: Open circuit in cable connection or internal sensor wiring.

   • Solution: Replace the cable or sensor.

2. Bias voltage approaches zero

   • Cause: Open circuit in cable connection or internal sensor wiring.

   • Solution: Replace the cable or sensor.

3. Bias voltage deviates significantly (outside ±A range of normal bias voltage)

   • Cause 1: Malfunction in the sensor's internal circuitry.

     • Solution: Replace the sensor.

   • Cause 2: Environmental temperature fluctuations causing voltage drift.

     • Solution: Install a thermal insulation sleeve or replace the sensor.

II. Unstable Bias Voltage

• Bias voltage fluctuates uncontrollably

  • Cause: Unstable internal circuitry in the sensor.

  • Solution: Replace the sensor.

III. Correct Bias Voltage

• Sensor failure despite normal bias voltage

  • Cause: Damage to the sensor's internal sensing element.

  • Solution: Replace the sensor.

I. Low Sensitivity

1. Bias voltage equals the supply voltage

   • Cause: Sensor aging or material instability.

   • Solution: Bake the sensor within its operating temperature range. Note: Sensitivity may temporarily recover but will generally degrade again over time.

2. Degradation of the piezoelectric coefficient in the sensor's sensing element

   • Cause: Long-term use or environmental stress.

   • Solution: Recalibrate the sensor.

II. Excessive Sensitivity Deviation

• Sensitivity deviation under non-ambient temperatures

  • Cause: Excessive temperature response coefficient of the piezoelectric material.

  • Solution: Select sensors with smaller temperature response coefficient deviations.

  • 
    

I. Poor System Low-Frequency Response

1. Sensor’s low-frequency cut-off frequency is too high

   • Cause: The sensor’s inherent low-frequency response is insufficient.

   • Solution:

     • Check the sensor’s low-frequency response (via time constant measurement).

     • Replace with sensors with superior low-frequency performance.

2. Inadequate low-frequency cut-off of equipment (constant current voltage source/charge amplifier)

   • Cause: The connected devices limit the system’s low-frequency capability.

   • Solution: Select constant current sources/charge amplifiers with appropriately low cut-off frequencies.

II. Poor Low-Frequency Signal-to-Noise Ratio (SNR)

• Excessive sensor low-frequency noise

  • Cause: SNR degrades significantly at low frequencies.

  • Solution: Use sensors meeting low-frequency SNR specifications.

III. External Signal Interference

• Transient environmental temperature variations

  • Cause: Temperature fluctuations distort measurements.

  • Solution:

    • Install thermal insulation sleeves on sensors.

    • Select sensors with low temperature response coefficients.

I. High-Frequency Signal Amplification

1. Distortion caused by sensor mounting method

   • Cause: Poor mechanical contact or resonance due to mounting.

   • Solution:

     • Adjust the mounting method to improve contact stiffness.

     • Use rigid mounting techniques (e.g., screws instead of adhesives) to enhance the sensor’s high-frequency range.

2. Low resonant frequency of the sensor’s internal sensing element

   • Cause: Limited high-frequency response due to sensor design.

   • Solution: Replace with sensors featuring higher resonant frequencies and superior high-frequency performance.

3. Poor stiffness of the sensor’s insulated mounting base

   • Cause: Mechanical damping or resonance from low-stiffness insulation.

   • Solution: Replace the base with a high-stiffness insulated mounting base.

II. High-Frequency Signal Attenuation

• Insufficient constant current from the voltage source during long-distance signal transmission

  • Cause: Current limitations reduce high-frequency signal integrity.

  • Solution: Select a constant current voltage source with adequate current output based on signal frequency and amplitude requirements.

I. Signal Output Attenuation

1. Reduced measurement range due to low supply voltage

   • Cause: Depleted battery or incorrect voltage supply.

   • Solution: Replace the battery or correct the battery voltage.

2. Bias voltage exceeding specifications due to ambient temperature variations

   • Cause: Temperature drift affecting sensor stability.

   • Solution: Use sensors with stable bias voltage performance.

3. Nonlinearity of the sensor

   • Cause: Sensor output deviates from linear response at high amplitudes.

   • Solution: Replace with sensors featuring larger measurement ranges.

4. Insufficient constant current from the voltage source during long-distance signal transmission

   • Cause: Current limitations distorting signal integrity.

   • Solution: Select a constant current voltage source with adequate current output based on signal frequency and amplitude.

II. Unstable Bias Voltage

• Output signal superimposed with high-frequency harmonics

  • Cause: Resonance effects from the sensor’s inherent frequency response.

  • Solution: Replace with sensors featuring higher resonant frequencies.

I. Unstable Signal Fluctuation

• Output signal instability due to transient temperature variations affecting bias voltage

  • Cause: Rapid temperature changes causing bias voltage drift.

  • Solution: Use sensors with stable bias voltage performance.

II. External Environmental Noise Interference

1. Ground loop noise

   • Cause: Multiple grounding points creating current loops.

   • Solution: Avoid multi-point grounding and use electrically isolated sensors.

2. Electromagnetic interference (EMI)

   • Cause: EMI from nearby electronic devices.

   • Solution: Use sensors with double-layered shielded housing.

3. Strong acoustic field interference

   • Cause: High-intensity sound waves inducing mechanical noise.

   • Solution: Mitigate using double-layered shielded housing on sensors.

4. Transient temperature fluctuations

   • Cause: Temperature shifts affecting ultra-low-frequency, high-sensitivity sensors.

   • Solution: Install thermal insulation sleeves on sensors.

5. Base strain interference at the measurement point

   • Cause: Mechanical strain from the mounting surface.

   • Solution:

     • Use shear-type accelerometers with low base strain sensitivity.

     • Minimize the contact area between the sensor and the measured object.

III. Measurement System Noise

1. Sensor electrical self-noise

   • Cause: Intrinsic noise from the sensor’s circuitry.

   • Solution: Verify sensor noise levels and select sensors with appropriate SNR (signal-to-noise ratio).

2. Cable-induced electrical noise

   • Cause: Poor-quality cables (common with charge-output sensors).

   • Solution: Replace with high-quality low-noise shielded cables.

3. Power supply noise

   • Cause: Noise from AC/DC power sources.

   • Solution: Use low-noise power supplies or switch to battery power.

4. Data acquisition system range settings

   • Cause: Improper range selection amplifying noise.

   • Solution: Select an appropriate measurement range to optimize signal resolution.