How to Conduct Scientific Procurement and Quality Evaluation Through Key Pressure Sensor Parameters

In the fields of industrial automation, energy, environmental protection, mechanical manufacturing, and infrastructure, pressure sensors are among the most fundamental and critical measuring components. An unreasonable selection often leads to measurement distortion, frequent failures, and even system safety hazards.

For procurement or technical personnel participating in project selection for the first time, facing pressure sensors with different ranges, accuracies, output modes, and structural forms can be overwhelming. Based on engineering application experience, this article systematically outlines the parameters that must be emphasized during pressure sensor procurement and further explains how to evaluate pressure sensor quality and reliability.

I. Why Pressure Sensor Procurement Must Be Based on Parameters Rather Than Price

In actual projects, pressure sensors are not “universal components.” Different operating conditions impose significantly different requirements on measurement range, accuracy stability, media adaptability, and electromagnetic environments.

If price alone is used as the primary decision criterion, common problems include:

• Improper range selection, leading to fatigue failure due to long-term full-scale operation

• Accuracy mismatch, causing continuous accumulation of system control deviations

• Media incompatibility, resulting in corrosion or diaphragm damage

• Insufficient anti-interference capability, causing severe signal fluctuations

Therefore, systematic selection based on key parameters is the fundamental principle of pressure sensor procurement.

II. Core Parameters That Must Be Considered in Pressure Sensor Procurement

1. Range Selection: The Foundation of Safety and Service Life

Range is the most intuitive and also the most frequently misused parameter of pressure sensors.

In engineering practice, it is recommended to follow these principles:

• Normal operating pressure should be within 60%–80% of the rated range

• Possible abnormal system pressures must not exceed the maximum allowable overload

• Sufficient safety margin should be reserved for pulsating or impact pressure conditions

For example, if the system operates at 6 MPa for long periods, choosing a 10 MPa range instead of 6 MPa can significantly improve stability and service life.

2. Accuracy Grade: Matching System Requirements, Not Simply Higher Is Better

Pressure sensor accuracy is usually expressed as %FS, including:

• Nonlinearity

• Repeatability

• Hysteresis error

Selection should be based on overall error allocation of the measurement and control system:

• General process control: 0.5%FS or 0.25%FS

• Energy monitoring and equipment protection: 1.0%FS is sufficient

• Precision processes or calibration systems: 0.1%FS or higher

Additional error sources should not be ignored:

• Zero drift

• Temperature coefficients (zero and full scale)

• Long-term stability

Reasonable accuracy selection often achieves the optimal balance between performance and cost.

3. Measured Media: Determining Long-Term Reliable Operation

Pressure sensors are in direct contact with the measured media, making media compatibility critical.

The following information must be clarified before procurement:

• Media type (gas / liquid / mixture)

• Chemical composition and concentration

• Operating temperature range

• Presence of corrosive, crystallizing, or particulate substances

Different diaphragm and interface materials have distinct applicability ranges, for example:

• Stainless steel for most industrial fluids

• Special coatings or isolation diaphragms for highly corrosive media

• Hygienic structures for food and pharmaceutical industries

Media mismatch is one of the main causes of premature pressure sensor failure.

4. Pressure Type Selection: Gauge, Absolute, and Differential Must Not Be Confused

According to reference pressure, pressure sensors are classified as:

• Gauge pressure: referenced to local atmospheric pressure

• Absolute pressure: referenced to absolute vacuum

• Differential pressure: measuring the difference between two pressure points

• Negative pressure: pressure below atmospheric pressure

Typical application distinctions include:

• Pipelines: usually gauge pressure

• Vacuum systems: absolute or negative pressure

• Liquid level in sealed vessels: differential pressure preferred

If the pressure type is selected incorrectly, valid data cannot be obtained regardless of accuracy.

III. Load Characteristics of Pressure Sensors and System Matching

1. What Are Load Characteristics of Pressure Sensors

When a pressure sensor is connected to a measurement system, it may influence the measured object or signal loop, causing deviation from the true value. This phenomenon is known as the load effect.

Load characteristics exist not only between the sensor and the media, but also between:

• The sensor and data acquisition modules

• Transmitters and control systems

2. Load Requirements for Current and Voltage Outputs

Common analog output types include:

• 4–20 mA current signals

• 0–10 V voltage signals

In engineering applications:

• Current signals offer stronger anti-interference capability and are more suitable for industrial sites

• Voltage signals have higher requirements for load impedance

Typical requirements are:

• Current output load ≤ (Us − 7.5) ÷ 0.02 Ω

• Voltage output load ≥ 100 kΩ

Proper load matching helps improve measurement stability and signal integrity.

IV. How to Inspect and Evaluate Pressure Sensor Quality

1. Importance of Anti-Interference Capability Testing

In industrial environments, pressure sensors often face various electromagnetic interferences:

• Surges: transient impacts caused by lightning or large equipment switching

• Burst pulses: groups of high-frequency spike interferences

• Electrostatic discharge: accumulated static electricity released by personnel or equipment

Insufficient anti-interference capability often manifests as:

• No signal output

• Abnormal display

• Instant sensor damage

2. Accuracy and Consistency Testing Methods

Pressure sensor accuracy testing typically uses:

• High-precision pressure sources

• High-grade multimeters (0.01% accuracy)

Through multi-point loading and unloading tests, the following can be verified:

• Whether actual accuracy meets specifications

• Repeatability and linearity

• Zero and full-scale stability

These are important criteria for evaluating pressure sensor quality.

Frequently Asked Questions (FAQ)

Is choosing a larger range always safer?
Not necessarily. An excessively large range may reduce resolution and affect measurement accuracy.

Is 4–20 mA always better than 0–10 V?
In industrial environments, current signals are more stable, but selection should still be based on system architecture.

Why do pressure sensors with the same parameters vary greatly in price?
Differences often lie in sensing element quality, temperature compensation, anti-interference design, and long-term stability.

Conclusion

Pressure sensor procurement is not a simple price comparison, but a comprehensive technical decision based on operating conditions, system structure, and long-term reliability. Only by thoroughly understanding key parameters such as range, accuracy, media compatibility, pressure type, load characteristics, and anti-interference capability can the right pressure sensor be selected for project requirements.

Nexisense continues to deepen its expertise in pressure measurement, committed to providing stable, reliable, and long-term pressure sensors and system solutions for various industries, offering a solid data foundation for engineering applications.