Comprehensive Analysis of Pressure Transmitter Selection Principles: From Type Determination to Accuracy and Stability Evaluation

In industrial automation systems, pressure transmitters not only perform the fundamental function of data acquisition, but also directly affect control accuracy, equipment safety, and system reliability. Faced with a wide variety of pressure transmitter products with significant structural differences, how to conduct scientific selection based on actual operating conditions is a critical issue that must be addressed in engineering design and equipment procurement.

Based on engineering application experience, this article systematically summarizes three core stages of pressure transmitter selection:
The first step is to select the correct type, the second step is to select the appropriate accuracy, and the third step is to clearly evaluate stability, helping to build a long-term reliable pressure measurement system.

I. Step One in Selection: Determine the Pressure Transmitter Type Based on the Measurement Object and Environment

The principles, structures, and packaging forms of pressure transmitters vary significantly. Before selecting any parameters, the first issue to resolve is not “how accurate,” but which type of pressure transmitter should be used.

1. Overall Analysis from Measurement Purpose and Object

Before actual measurement, the following factors should be systematically reviewed:

The measured medium is gas, liquid, or a mixed medium
The pressure is static, dynamic, or pulsating pressure
Whether high temperature, corrosion, vibration, or impact exists
Whether the measurement purpose is process control, monitoring and alarm, or data analysis

These factors directly determine the structural form and protection design of the pressure transmitter.

2. Impact of On-Site Operating Conditions on Selection

In engineering sites, the following conditions often play a decisive role:

Measurement range: normal operating pressure and possible overload conditions
Installation space: restrictions on transmitter size and interface form
Measurement method: contact measurement or diaphragm-isolated measurement
Signal transmission: wired 4–20 mA, RS485, or wireless communication
Component sourcing: balance between domestic and imported solutions in terms of technology and cost

These conditions are usually “hard constraints.” Once determined, the selectable range of pressure transmitters will be significantly narrowed.

3. Core Objective of the First Selection Stage

The objective of this stage is not to select the “best” pressure transmitter, but to eliminate unsuitable types and ensure that the selected product can be structurally and functionally compatible with on-site operating conditions over the long term.

Only after completing this step does subsequent performance parameter selection become meaningful.

II. Step Two in Selection: Understanding Pressure Transmitter Accuracy from System Requirements

Among the technical specifications of pressure transmitters, accuracy is the most concerned and also the most easily misunderstood parameter.

1. What Is Pressure Transmitter Accuracy

Pressure transmitter accuracy refers to the degree to which the measurement result approaches the true pressure value, usually expressed as a relative full-scale error, with the unit %FS.

Common accuracy classes of industrial instruments include:

0.1%FS
0.2%FS
0.5%FS
1.0%FS
1.5%FS

The smaller the numerical value of the accuracy class, the higher the accuracy.

2. Understanding the Concept of “Accuracy” from Three Dimensions

In engineering practice, accuracy is not a single concept, but a comprehensive reflection of multiple error factors:

Consistency between measurement results and true values, reflecting the combined effects of systematic and random errors
Consistency among multiple measurement results, reflecting the impact of random errors on measurement stability
Ability to control systematic errors, including temperature drift, linearity error, and zero offset

Therefore, accuracy depends not only on the sensing element, but is also closely related to compensation algorithms, manufacturing processes, and the operating environment.

3. Accuracy Selection Should Serve Measurement Objectives

In practical applications:

Qualitative monitoring or trend analysis does not require blindly pursuing high accuracy
Process control and energy management should select accuracy levels that match system errors
Quantitative analysis or metering applications require higher-accuracy pressure transmitters

Higher accuracy means higher cost; the key to selection lies in being “sufficient and stable.”

III. Step Three in Selection: Pressure Transmitter Stability Determines Long-Term Reliability

If accuracy determines whether measurements are correct, stability determines whether they can remain correct over the long term.

1. What Is Pressure Transmitter Stability

Stability refers to the ability of a pressure transmitter to maintain its output characteristics without significant changes during long-term use, usually expressed as annual drift, for example:

±0.1%FS/year

A pressure transmitter with poor stability, even if it has high initial accuracy, will gradually deviate from true values during long-term operation.

2. Main Factors Affecting Stability

Pressure transmitter stability is influenced by multiple factors:

Structural design and packaging processes
Sensor element materials and stress relief capability
Environmental temperature variations, vibration, and humidity
Power supply quality and electromagnetic interference

Therefore, the on-site environment should be fully evaluated during the initial selection stage to avoid long-term exposure of the pressure transmitter to conditions beyond its design limits.

3. Relationship Between Stability and Calibration Cycle

Stability directly determines:

Recalibration cycles
Maintenance costs
Long-term data availability

In applications where maintenance is inconvenient or frequent shutdowns are not feasible, stability requirements for pressure transmitters are particularly stringent.

IV. Summary of the Overall Engineering Selection Logic

Pressure transmitter selection is not a simple comparison of parameters, but a systematic engineering process from external conditions to internal performance:

First, evaluate on-site conditions and measurement objects to determine the transmitter type
Then, select an appropriate accuracy level based on system requirements
Finally, evaluate long-term operation with a focus on stability

Only by following this logic can situations where “parameters meet specifications but applications fail” be avoided.

Frequently Asked Questions (FAQ)

Is a pressure transmitter with high accuracy but average stability usable?
It may be usable in the short term, but in long-term operation, errors will gradually accumulate, making it unsuitable for critical measurement points.

Do all operating conditions require high-stability pressure transmitters?
For continuous operation, difficult maintenance conditions, or critical control points, high stability is particularly important.

Should price be considered first during selection?
Price should only be considered after technical requirements are satisfied.

Conclusion

The proper selection of pressure transmitters is the prerequisite for the reliable operation of pressure measurement systems. From type determination and accuracy selection to stability evaluation, every step directly affects measurement quality and service life.

By systematically understanding pressure transmitter selection principles and making rational decisions based on specific operating conditions, the true value of pressure transmitters in industrial measurement can be fully realized.

Nexisense continues to focus on the field of pressure measurement and is committed to providing stable, reliable, and engineering-proven pressure transmitter solutions for various application scenarios.