Detailed Explanation of Nexisense Pressure Sensor Measurement Modes: A Comprehensive Guide to Gauge, Absolute, and Vacuum Pressure

In industrial automation, process control, and equipment monitoring, pressure sensors are indispensable core components. They convert medium pressure signals into standard electrical signals, providing real-time data for control systems. The Nexisense pressure sensor series is renowned for high precision and strong stability, supporting multiple measurement modes to adapt to various working conditions. Starting from definitions, this article systematically explains the three main measurement modes—gauge, absolute, and vacuum—and provides practical guidance combined with principles, structures, advantages, application scenarios, and maintenance.

Definition and Role of Pressure Sensors

A pressure sensor (Pressure Transducer) is a device or apparatus that can sense pressure and convert it into a usable electrical signal according to specific rules. It usually consists of a pressure-sensitive element and a signal processing unit, and is widely used to monitor the pressure status of gases, liquids, or steam.

Nexisense products cover the full range from micro-pressure to high pressure, supporting 4-20mA, 0-10V, or digital outputs. This facilitates connection to PLC, DCS, or SCADA systems, providing a reliable basis for safe operation and process optimization.

Analysis of Working Principles

The working principle of a pressure sensor is based on the physical characteristics of the pressure-sensitive element. Core elements often use diffused silicon, ceramics, or metal strain gauges. When pressure is applied, it causes the diaphragm to deform, generating changes in resistance or capacitance, which are then amplified and linearized to output a standard signal.

Different measurement modes are essentially differences in the reference pressure: Gauge pressure uses atmospheric pressure as the baseline, absolute pressure uses a vacuum as the baseline, and vacuum (negative) pressure focuses on the portion below atmospheric pressure. Nexisense utilizes high-performance pressure-sensitive chips and isolated diaphragm designs to ensure long-term stability and anti-overload capabilities.

Internal Structure Analysis

Nexisense pressure sensors feature a compact and durable structure, typically including a sensitive diaphragm, isolation diaphragm, signal processing circuit, and housing. The sensitive diaphragm directly senses the pressure, while the isolation diaphragm protects the chip from corrosive media. The housing is mostly made of 304 or 316L stainless steel, with protection ratings reaching IP65 or higher.

The junction box supports shielded cables, and some models integrate temperature compensation circuits to reduce the impact of temperature drift. The overall modular design facilitates on-site installation and maintenance.

Significant Advantages

Nexisense pressure sensors perform excellently across all measurement modes. High accuracy (typically ±0.25% FS), wide range coverage, and strong anti-interference capabilities are their core highlights. The isolated design effectively handles corrosion and overpressure, with fast response times (millisecond level) suitable for dynamic monitoring.

Various output modes and interface compatibility reduce the difficulty of system integration. These features together guarantee the reliable operation of equipment in harsh environments.

Detailed Explanation of the Three Main Measurement Modes

1. Gauge Pressure Measurement

Gauge Pressure refers to the portion of the medium pressure that exceeds the local atmospheric pressure, also known as relative pressure. One side of the sensor feels the medium pressure, while the other side is open to the atmosphere (or connected to the atmosphere through a vent hole).

Gauge pressure is commonly used in daily industrial settings, such as hydraulic systems, compressor outlets, and pipeline pressure monitoring. Typical ranges include 0-1MPa, 0-10MPa, etc.

2. Absolute Pressure Measurement

Absolute Pressure is the absolute pressure referenced against a vacuum; it is the sum of all pressures within the medium space. The internal part of the sensor usually uses a sealed cavity, which contains a vacuum or a fixed reference pressure.

Absolute pressure is suitable for scenarios where the influence of atmospheric pressure needs to be eliminated, such as vacuum systems, barometric altimeters, and aerospace equipment. Ranges are often expressed in kPa abs or bar abs.

3. Vacuum (Negative) Pressure Measurement

Vacuum Pressure (Negative Pressure) refers to a pressure state lower than atmospheric pressure, also known as vacuum degree. A vacuum pressure sensor is essentially a gauge pressure sensor, but with the range extended to negative values (e.g., -100kPa to 0kPa).

Commonly found in vacuum pumps, suction cup systems, and vacuum adsorption equipment. During measurement, care must be taken to avoid excessive vacuum causing diaphragm damage.

Diverse Application Scenarios

Gauge pressure sensors are widely used in booster cylinders, superchargers, gas-liquid boosters, presses, compressors, and air conditioning refrigeration equipment. Absolute pressure sensors are common in vacuum packaging, semiconductor manufacturing, and meteorological instruments. Vacuum sensors are applied in medical suction devices, vacuum forming machines, and laboratory vacuum systems.

Nexisense products cover these fields, supporting customized ranges and interfaces to help different industries achieve precise control.

Selection and Installation Precautions

When selecting, it is necessary to clarify the medium type (gas/liquid/corrosive), range, accuracy requirements, and measurement mode. Gauge pressure is the most common; absolute pressure is suitable for occasions with large atmospheric pressure changes; vacuum pressure requires attention to overload protection.

During installation, the sensor should be placed in a position with stable pressure and suitable temperature, avoiding vibration and heat sources. Pipeline installation requires an isolation valve for easy maintenance. Ensure reliable sealing and that the vent hole (for gauge types) faces downward to prevent water accumulation.

Maintenance and Upkeep Guide

Daily checks should ensure wiring is firm and the diaphragm is clean to avoid clogging. Regular calibration (recommended once a year) should be performed to record zero drift. Corrosive media require the selection of isolated diaphragm types. When not in use for a long time, store in a dry, non-corrosive environment.

Correct maintenance can significantly extend service life and maintain measurement accuracy.

Technical Parameters at a Glance

Frequently Asked Questions

What is the difference between gauge and absolute pressure?
Gauge pressure references atmospheric pressure and its value changes with weather; absolute pressure references a vacuum and the value is stable.

Can vacuum sensors measure positive pressure?
Some models support bidirectional ranges, but the specifications must be confirmed.

How to judge if a sensor is damaged?
If the zero drift exceeds the standard or the output is abnormal, calibration or replacement is required.

How to select for corrosive media?
Priority should be given to models with ceramic or titanium alloy isolation diaphragms.

Are there requirements for installation position?
Stay away from vibration and heat sources; the probe should be in full contact with the medium.

Conclusion

The measurement modes of pressure sensors—gauge, absolute, and vacuum—each have applicable scenarios, directly determining the meaning and reliability of the measurement results. Nexisense provides precise and stable pressure monitoring solutions through advanced design and diverse products. Understanding the principles of different modes, rational selection, and standardized installation and maintenance are the keys to achieving efficient and safe production. In the process of industrial intelligence, choosing the right pressure sensor and applying it scientifically will bring significant value to your equipment operation and process optimization.