Core Technical Principles of Diffused Silicon Wheatstone Bridge Sensors

In the field of industrial automation, the measurement accuracy of the MT-A pressure transmitter directly affects production safety and efficiency. This article provides an in-depth analysis of the core technical principles of diffused silicon Wheatstone bridge sensors, comprehensively revealing how to achieve high-accuracy measurement of ±0.1%FS from material properties, structural design to calibration processes, and offering professional solutions for common faults of models such as PT-PT202 and CS-PT300.

The diffused silicon Wheatstone bridge pressure sensor uses the piezoresistive effect of semiconductor silicon material to form a Wheatstone bridge on the silicon diaphragm through precision diffusion processes. When external pressure acts on the sensor, the silicon diaphragm undergoes slight deformation, causing changes in the bridge resistance values and thereby outputting an electrical signal proportional to the pressure. This principle determines its characteristics of high sensitivity and fast response speed, making it particularly suitable for dynamic pressure measurement scenarios such as hydraulic and pneumatic control systems.

Taking the domestic high-temperature pressure transmitter BYP310 diffused silicon pressure sensor as an example, it uses a 316 stainless steel isolation diaphragm and silicone oil transmission system, which not only ensures media compatibility, but also controls temperature drift within ±0.05%FS/℃ through a temperature compensation circuit, which is the key to achieving 0.25 class high accuracy.

Impact of Material Properties on Accuracy

1.Silicon wafer purity: N-type monocrystalline silicon wafers are used, with resistivity controlled at 1-10Ω·cm, ensuring the piezoresistive coefficient remains stable between 110-120
2. Packaging material: The 304/316 stainless steel housing can withstand 300MPa overload pressure while avoiding mismatch in coefficients of thermal expansion
3. Filling silicone oil: High-purity fluorosilicone oil maintains stable viscosity within the range of -30～+85℃, reducing pressure transmission loss

Structural Design and Process Optimization Solutions

To achieve the nominal 0.1 class accuracy of models such as JPB-JPB2300, it is necessary to overcome three major technical bottlenecks:

Especially in wide-range models such as CYB-28, multi-sensor fusion technology is adopted, and segmented calibration from 0～0.01MPa to 0～250MPa is carried out to control the full-scale comprehensive error within 0.25 class.

Breakthroughs in Temperature Compensation Technology

• Dual-bridge compensation: the main bridge measures pressure, while the auxiliary bridge is dedicated to temperature compensation
• Digital temperature compensation: a built-in PT1000 temperature sensor performs real-time correction through DSP
• Segmented compensation algorithm: 5 compensation intervals are set within the ambient temperature range of -20～85℃

Calibration and Fault Diagnosis Practices

According to common fault statistics of the YB-YB3011 pressure transmitter, approximately 65% of accuracy issues result from improper calibration:

1. Zero-point calibration: Under no-pressure conditions, adjust the Zero Trim parameter through the HART protocol, allowing ±8% range adjustment
2. Full-scale calibration: Apply a standard pressure source and use the Span Trim function for ±20% range fine-tuning
3. Linearity verification: Use the 5-point method (0%,25%,50%,75%,100%) to verify FS nonlinearity

For faults caused by unclear wiring diagram identification of SWT-SWT131, note the following:
• Red wire: power supply positive (+24VDC)
• Black wire: signal output (4-20mA)
• Shield layer: must be grounded at one end only

Engineering Practices for High-Accuracy Measurement

In high-temperature scenarios such as turbo-generator units, it is recommended to select products similar to domestic high-temperature pressure transmitter BYP310, which feature:
• Wide-range adaptability to media temperatures of -30～+85℃
• 1 millisecond fast response capability
• Traceability assurance through laser marking

For long-term operating equipment such as TS-802, the following should be carried out every 12 months:
1. Seal integrity test （helium mass spectrometer leak detector）
2. Zero drift test （8-hour no-pressure monitoring）
3. Insulation resistance measurement （500VDC megohmmeter）

Summary and Recommendations

By optimizing diffused silicon sensor materials, improving packaging processes, and enhancing temperature compensation systems, modern pressure transmitters have now been able to stably achieve 0.1 class accuracy. For specific needs such as PT-A pressure transmitter calibration, it is recommended to:

• Give priority to products with laser traceability markings
• Regularly verify with standard pressure calibration equipment
• Strictly follow the installation specifications for interfaces such as Gl/4 and M20×1.5

If you need a complete technical solution for MT-A pressure transmitter accuracy optimization, please contact our engineering team for professional support.