What is a pressure scanner?

Gensors DAS-P16 Pressure Scanner

"Pressure Scanner" or "Pressure Multiplexer". This is a common professional device in fields such as fluid 

mechanics, aerospace, and automotive wind tunnel testing.

Core Definition

A Pressure Scanner is an electronic, computer-controlled multi-channel pressure switching and measurement 

system. Its core function is to sequentially or rapidly measure pressure from multiple input points and convert 

the pressure value at each point into an electrical signal output.

You can think of it as a "multiplexer for pressure data" or an "electronic switch" for pressure ports.

Why is it needed? (Comparison with Traditional Methods)

Before the advent of pressure scanners, how did engineers measure a large number of pressure points 

(for example, hundreds of pressure taps on an aircraft wing model surface)?

Traditional Method: Single Sensor + Mechanical Scanivalve

Uses a single pressure sensor connected, via a motor-driven mechanical rotary valve, to different pressure 

ports one by one.

Disadvantages:

Very Slow: Switching one channel could take several seconds; measuring hundreds of points could take minutes, 

making it impossible to capture transient changes.

Bulky: Complex mechanical structure.

Low Reliability: Mechanical parts are prone to wear and tear, with risk of air leaks.

Poor Synchronization: Since measurements are sequential, data from different points are not acquired at the 

"same moment," introducing errors for unsteady flow fields.

Modern Method: Pressure Scanner

Uses a common high-precision sensor (or equips each channel with a miniature sensor), with high-speed 

switching via solid-state electronic switches (e.g., solenoid valves).

Advantages:

Very Fast: Capable of scanning tens of thousands of channels per second, enabling the capture of dynamic 

pressure changes.

High Accuracy: The core sensor is highly accurate, and since all channels share the same sensor, calibration 

errors between multiple sensors are avoided.

Excellent Synchronization: Although still sequentially sampled, the speed is so high that data from all channels 

can be considered "simultaneous."

Compact and Reliable: Electronic design, no moving parts, small size, long lifespan.

Automation: Fully computer-controlled, easy to integrate into data acquisition systems.

Primary Working Principles

Single High-Precision Sensor Type (Common)
Dozens of pressure inlets are connected to a common, high-precision pressure sensor via an array of precision 

solenoid valves.
The computer controls these valves, opening only one at a time to allow the pressure from that channel to be measured by the sensor. It then closes that valve and rapidly opens the next one.
Automatic zero calibration is performed before measurement to eliminate errors like thermal drift.

Multi-Miniature Sensor Integrated Type (More Modern)
A miniature, strictly matched and calibrated MEMS (Micro-Electro-Mechanical Systems) pressure sensor chip 

is integrated for each pressure channel.
The electronic switch no longer switches the pneumatic path, but instead switches the electrical signal outputs 

of these sensors to the data acquisition system.
Advantage: Speed can be maximized because the pneumatic path is always connected, avoiding potential pressure 

disturbances and delays caused by valve switching.

Key Features and Technical Parameters

The performance of a pressure scanner is primarily evaluated based on the following parameters:

Number of Channels: Typically modules with 16, 32, 48, 64 channels, etc. Multiple modules can be combined to 

expand to hundreds of channels.

Pressure Range: The range of pressures it can measure (e.g., ±1 psi, ±5 psi, 0-15 psi). The appropriate range must 

be selected based on the experiment to ensure accuracy.

Accuracy: Usually expressed as a percentage of Full Scale (%FS), e.g., 0.05% FS. This is one of the most important 

metrics.

Scan Rate: The number of channels that can be switched and measured per second (e.g., 50,000 channels/second).

Pressure Media Compatibility: Compatibility with which fluids (air, oil, water, etc.).

Operating Temperature Range: Especially important for internally integrated sensors, temperature stability is crucial.

Communication Interface: How it communicates with the host computer, e.g., Ethernet, USB, RS-232, etc.

Main Application Areas

Aerospace: Measuring surface pressure distribution on aircraft and rocket models in wind tunnel tests is its most 

classic and primary application.

Automotive Industry: Automotive wind tunnel testing, measuring surface pressure on car bodies to optimize 

aerodynamic performance (reduce drag, minimize wind noise).

Turbomachinery: Measuring complex pressure fields inside gas turbine engines, compressors, and fan blades.

Universities and Research Institutions: Conducting various fundamental research in fluid mechanics and aerodynamics.

Environmental Monitoring: Monitoring multi-point atmospheric pressure or ventilation duct pressure.

Summary

In simple terms, a pressure scanner is a "super switch" that uses electronic and automated methods to efficiently, 

rapidly, and accurately measure a large number of pressure points. It has revolutionized the traditional cumbersome 

and inefficient measurement methods and is an indispensable key device in modern aerodynamic experiments 

and fluid measurement.