Pressure Measurement · Beginner Guide
Pressure Sensor: The Ultimate Guide for Beginners
Pressure sensor is a necessary device in industrial production and manufacturing, but how much do you know about the pressure sensor? This guide covers 11 points to help you better understand the pressure sensor.
Audience: Beginners Topics: 11 Points Products: GPT Series Read: ~12 min
From the definition and working principle to types of pressure measurement, specifications, output signals, units, and applications — everything you need to choose and use pressure sensors with confidence.
01What Is a Pressure Sensor?
Pressure sensor is a device that can sense the pressure. It can convert the pressure signal into the electrical signal and then outputs the corresponding pressure value with the help of a backend display instrument. It is widely used in some industrial applications such as HVAC, process control, water supply, pipeline pressure monitoring, which greatly improves the efficiency of industrial production and ensures safety in industrial manufacturing.
02Working Principle of Pressure Sensor
According to different working principles, pressure sensors can be divided into piezoresistive, piezoelectric, capacitive, and resonant pressure sensors.
Piezoresistive Pressure Sensor
Measures pressure by the Piezoresistive Effect Principle. Four resistors on the sensor chip vary and form a Wheatstone bridge when pressure deforms the diaphragm. A signal processing circuit converts the pressure change into a signal change. Learn more.
Piezoelectric Pressure Sensor
Uses the Piezoelectric Effect: pressure forms an electric charge proportional to the pressure. Sensitive elements include quartz, lead zirconate titanate (PZT), or piezoelectric polymers (PVDF). Usually more expensive due to crystal material prices.
Capacitive Pressure Sensor
Uses changes in capacitance to monitor pressure changes. When pressure acts on the diaphragm, the capacitance between the film and the fixed electrode changes, deriving an electrical signal through the measurement circuit.
Resonant Pressure Sensor
Uses a resonant element to convert pressure signals into electrical signals. Main types: vibrating string, vibrating cylinder, diaphragm, and quartz crystal resonant.
03Types of Pressure Measurement
Gauge Pressure
Also known as relative pressure; refers to pressure higher than atmospheric pressure based on atmospheric pressure, which can be measured by a pressure gauge.
Absolute Pressure
Refers to the pressure value relative to absolute zero pressure. If gauge pressure is positive, then absolute pressure − local atmospheric pressure = gauge pressure.
Sealed Gauge Pressure
Encapsulates the local atmospheric pressure of the production location; if the product is used in other places, errors will occur.
Differential Pressure
The difference between two pressures: p = p1 − p2.
04Pressure Sensor vs Transmitter
Pressure sensors and pressure transmitters are both devices that measure pressure to a certain extent. However, they differ in output signals and applications.
Sensor vs Transmitter
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Aspect
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Pressure Sensor
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Pressure Transmitter
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Output signal
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Millivolt signal
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Standard analog or digital signal after amplification
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Application
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Equipment integration, assembling transmitters, laboratory use
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Industrial control: pipeline monitoring, water treatment; direct connection to PLC, DCS or display instruments
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05Pressure Sensor Different Media Types
The pressure sensor has good media compatibility and can measure most gases, liquids, oils, as well as corrosive gases and liquids.
Air Pressure Sensor
Used in weather monitoring, HVAC systems, drones and aviation equipment, automotive electronics, and consumer electronics. For HVAC or air compressors, the GPT230 pressure sensor is a good choice.
Gas Pressure Sensor
Measures common gases such as natural gas, oxygen, and other gases, including suppressed, flammable, and explosive industrial gases with corresponding solutions.
Water Pressure Sensor
Used in water treatment, water supply, and agricultural irrigation to monitor water pipe pressure. Be careful of water hammer near pumps — instantaneous pressure may break the sensor.
Liquid Pressure Sensor
Measures chemicals such as acid and alkali solutions, sulfuric acid, methanol, and ethanol, as well as food and medicine related liquids like milk, juice, and beer.
Fuel Pressure Sensor
Measures the pressure of oil products such as diesel, gasoline, kerosene, transformer oil, lubricating oil, and cooking oil.
Corrosive Liquids and Gases
For corrosive media, material selection matters: Hastelloy, titanium alloy, 316L, PTFE, and PVDF are ideal anti-corrosion materials for the sensor shell.
06Pressure Sensor in Harsh Environment
Corrosive Medium
Stainless steel shells resist mild corrosion; for highly corrosive media, the GPT235 pressure sensor uses a PTFE shell. Shell materials can also be customized: Hastelloy, titanium alloy, PVDF, etc.
Explosive Environment
For industries like petrochemicals, products with explosion-proof function are required. GAMICOS has obtained the explosion-proof certificate for pressure sensors.
Hygienic Environment
In medicine and food fields, flat membrane pressure sensors are needed — easy to clean and free of dirt harboring. The GPT210 sanitary pressure sensor is proven in food and medicine.
07Pressure Sensor Specifications
Key Specifications at a Glance
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Parameter
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Description
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Pressure connection
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Threaded interface (G, NPT, BSPT, metric M20×1.5), plus flange, clamp, plug-in, and welding interfaces
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Pressure range
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Common units: MPa, KPa, Pa, bar, PSI. The range should not be too small (easy damage) or too large (inaccurate measurement)
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Electrical connection
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Hirschmann, Packard, aviation plug, and wire connection
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Power supply
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Common industrial supplies: 5V, 12V, and 24V DC. Overvoltage may damage the sensor; undervoltage causes unstable output
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Output signals
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Analog (current 4~20mA; voltage 0~5V, 0~10V, 0.5~4.5V) and digital (RS485, RS232, I2C)
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Medium
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Water, gas, oil; PTFE, PVDF or Hastelloy shells for corrosive media; gold-plated sensors prevent hydrogen embrittlement; heat sinks for high temperatures
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Accuracy
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Related to repeatability, nonlinearity, and hysteresis. GAMICOS common accuracy: 0.5%, 0.25%; some products reach 0.075% and 0.1%
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08Pressure Sensor Output Signal
Millivolt Output
Pressure sensors usually output millivolt signals. Unlike transmitters, they have no signal conditioning circuit and cannot directly output analog signals.
Current Output
Mainly 0~20mA and 4~20mA (more common). Not easily affected by noise; the 20mA upper limit avoids spark hazards and the 4mA lower limit detects broken wires.
Voltage Output
Common signals: 0~5V, 0~10V, 1~5V. Advantages: simple interface, direct ADC connection, short transmission distance, low cost.
Frequency Output
Converts pressure into a periodic signal with variable frequency (square wave, pulse). Strong anti-interference ability and controllable consumption for industrial automation, automotive electronics, and IoT.
Digital Output
Common digital outputs: I2C, RS485, RS232, Lora, NB-IoT, Bluetooth. Features: anti-interference, high precision, rich data, two-way communication, and compatibility.
09Pressure Sensor Units
Common Pressure Units and Conversions
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Unit
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Definition / Conversion
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Pascal (Pa)
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SI unit of pressure: one newton per square meter. 1Pa = 1N/m²
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Kilo Pascal (KPa)
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1KPa = 1000 Pa
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Bar
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1 bar = 100 KPa; from the Greek word "baro", meaning weight
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mmHG
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One millimeter of mercury under standard gravity: 1mmHg ≈ 133.322 Pa
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inHG
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One inch of mercury: 1inHg ≈ 3386.39 Pa
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PSI
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Pounds per square inch; more commonly used in the United States
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Atm
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Atmosphere: precisely equal to 101,325 pascals. 1atm = 101,325 Pa
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10Why Do You Choose the Pressure Sensor?
Accurate Process Control
Continuously monitor pressure in pipelines, containers, or reactors and feed the value back to control systems such as PLC and DCS. Abnormal pressure triggers timely feedback to avoid danger.
Maximize Economic Benefits
Greatly reduces labor through system automation — no point-by-point monitoring needed. Saves energy consumption and resource waste, maximizing cost efficiency and economic benefits.
Safety Assurance
Avoids safety accidents caused by high or low pressure. Explosion-proof and lightning-proof designs protect extreme environments such as wild, flammable, and explosive applications.
11Application of Pressure Sensor
Industrial Automation
Monitors pipeline and equipment pressure to reduce overpressure or underpressure accidents; abnormal pressure triggers emails or messages to notify staff for emergency repairs.
Auto Industry
Indispensable in engine systems, brake systems, turbocharger systems, and tire pressure monitoring systems.
Medical Care
Monitors patient physiological parameters and medical equipment. Used in ventilators, blood pressure monitors, infusion pumps, analgesic pumps, endoscopes, and more.
Environment Monitoring
Meteorological forecasting, hydrological monitoring (floods, droughts), industrial pollution control (waste gas and sewage discharge), and deep-sea exploration.
Aerospace
Monitors combustion chamber pressure, fuel hydraulic pressure, and lubricating oil pressure; vital in atmospheric data systems, life support systems, and rocket recovery systems.
Water Conservancy Project
Senses water pressure changes in real time for rivers, reservoirs, dams, irrigation systems, and water pipelines, supporting water resource management and flood prevention.
12Conclusion
The pressure sensor market has great prospects and plays an important role in various industries under industrial scenarios. The use of pressure sensors has greatly improved the efficiency of industrial production, reduced labor costs, and ensured the safety of industrial production.
13FAQs
What are world-famous pressure sensor brands?
World famous pressure sensor brands are: Honeywell, Siemens, Endress Hauser, Wika, Emerson, Yokogawa, etc.
What are the differences between a pressure sensor and pressure gauge?
Pressure sensors require external power supply, have high accuracy, can output electrical signals, and can be connected to back-end devices such as PLC and DCS. Pressure gauges display pressure values mechanically, do not require external power supply, have low accuracy, can output pressure values intuitively, and are low in price. Pressure sensors are used in automated control, high-precision, and remote monitoring scenarios; pressure gauges can be read directly on-site and suit low-cost occasions.
What are the differences between a pressure sensor and a pressure switch?
Pressure sensors output continuous electrical signals with high accuracy, can be used with controllers (PLC, DCS) to realize complex functions and be integrated into automation systems. They are usually expensive. When the pressure reaches the threshold, the pressure switch switches the circuit and outputs a discrete signal; its accuracy is low, usually 2.5%, and the cost is low with simple maintenance.
