A pressure sensor (Pressure Transducer) is a transmitter that can sense pressure signals and convert them into usable output electrical signals according to certain rules.
The pressure sensor usually consists of a pressure sensitive element and a signal processing unit. According to different test pressure types, pressure sensors can be divided into gauge pressure sensors, differential pressure sensors and absolute pressure sensors.

Today I will mainly introduce three common detection methods for pressure sensors. Hope it helps everyone.
1. Pressure test. The method of detection is to power the sensor. Use your mouth to blow the air hole of the pressure sensor. Use the voltage file of a multimeter to detect the voltage change at the output of the sensor. If the relative sensitivity of the pressure sensor is large. This amount of change will be obvious. If nothing has changed. You need to use a pneumatic source to apply pressure instead.
2. Zero point detection. Use the voltage file of a multimeter. Detect the zero output of the sensor under no pressure. This output is generally mV level voltage. If the technical specifications of the sensor are exceeded, the zero deviation of the sensor is out of range.
3. Detection of bridges. It mainly detects whether the circuit of the sensor is correct. It is generally a Wheatstone full-bridge circuit. Use the ohm file of the multimeter to measure the impedance between the input terminals and the impedance between the output terminals. These two impedances are the input and output impedances of the pressure sensor. If the impedance is infinite, the bridge is disconnected. It means there is a problem with the sensor or the definition of the pin is not correct.

The output signal of the two-wire pressure transmitter is generally 4-20MA. The supply voltage is 24VDC. The two wires are a red (representing positive 24V power supply), and a black or blue (representing positive signal output). The wiring method is that the red wire is connected to the positive source and the blue wire is connected to the signal positive, and then the power supply negative and the signal negative are shorted.
The three-wire pressure transmitter is generally a voltage output. Wire one (red power supply is positive), one black (power supply is negative), and one yellow (signal output is positive). The output ground is common to the power supply.

Oxygen plays an important role in the smelting process, chemical industry, national defense industry, and healthcare. However, the process of oxygen production and use is extremely prone to combustion and explosion.
The analysis is based on the mechanism of the “three elements” of combustion and explosion (combustible materials, oxidants, and excitation energy). The high-purity high-pressure oxygen transported in the oxygen pipeline is a very strong oxidant. The higher the purity, the higher the pressure, the stronger the oxidation, the more dangerous.
The potential sources of excitation energy for combustion or explosion are roughly the following: friction, compression heat, impact force, arc, resonance, etc.
In the construction of industrial oxygen pipelines, multiple cleaning processes such as derusting, scrubbing, sand blasting, blowing, degreasing, and acid cleaning should be carried out. Remove the oil and impurities in the pipeline to make it reach the condition of transporting oxygen medium. Check and accept according to relevant standards, and use it after passing the test.
For oxygen pressure measurement, choosing a clean instrument filled with inert oil not only improves the safety level, but also greatly reduces the risk of economic and time loss caused by maintenance or failure replacement.
Sino-Inst pressure sensor for oxygen measurement
Accuracy: ± 0.15% FS
Fill with Fluorolube® oil to ensure no oxidation reaction
Oil-free production process, oxygen-level cleaning process
Φ19mm standard OEM pressure / differential pressure sensor
Constant current / constant voltage power supply
All stainless steel 316L material

A pressure sensor is a device for pressure measurement of gases or liquids.  Pressure sensors can also be used to indirectly measure other variables such as fluid/gas flow, speed, water level, and altitude. Pressure sensors can alternatively be called pressure transducers, pressure transmitters, pressure senders, pressure indicators, piezometers, and manometers, among other names.
In short, a pressure sensor converts pressure into a small electrical signal, which is sent and displayed. Therefore, these are also commonly referred to as pressure transmitters. Two common signals used are 4 to 20 mA signals and 0 to 5-volt signals.
Most pressure sensors work using the piezoelectric effect. This is when the material generates a charge in response to stress. This stress is usually compressive, but may be twisted, bent, or vibrated.
Pressure sensors detect pressure and can determine the amount of pressure by measuring the charge.
The pressure sensor needs to be calibrated in order to know what voltage or milliamp (mA) signal corresponds to what pressure. This is the basic “zero” and “span” calibration or minimum and maximum, which is a common job for maintenance personnel.
Read more about: What is a pressure sensor and how it works? 

Air pressure sensor is an instrument used to measure the absolute pressure of gas. Air pressure sensor is mainly suitable for physical experiments related to gas pressure. It can also measure dry, non-corrosive gas pressure in biological and chemical experiments.
The main sensing element of the air pressure sensor of the air compressor is a thin film that is sensitive to the pressure of the air pressure and a thimble opening control. In the circuit, it is connected with a flexible resistor. When the pressure of the measured gas decreases or increases, the thin film deforms to drive the ejector pin, and the resistance of the resistor will change. The resistance of the resistor changes. The signal voltage of 0-5V is obtained from the sensing element, and is received by the data collector after A / D conversion, and then the data collector transmits the result to the computer in an appropriate form.
The main component of many air pressure sensors is a variable-capacitance silicon capsule. When the external atmospheric pressure of the variable-capacitance silicon membrane box changes, the thimble moves, and the single crystal silicon membrane box elastically deforms with it, thereby causing a change in the capacitance of the parallel plate capacitor of the silicon membrane box to control the air pressure sensor.
More about Gas Pressure Sensor.

The pressure sensor is a device that detects pressure and converts the pressure signal into an electrical signal and outputs it linearly. Common types include strain gauge, piezoresistive, capacitive, piezoelectric, and vibration frequency pressure sensors.
We use strain gauge pressure sensors as an introduction. It is mainly composed of 4 parts: elastomer, strain gauge, measuring circuit and transmission cable.
Strain gauge pressure sensor measurement principle: When the pressure sensor elastic body is deformed under the action of external force. The strain gauge attached to the elastic body then bends. The resistance of the strain gauge changes. Then the measurement circuit converts the change in resistance into an electrical signal (usually a millivolt signal).
Elastomer: Elastomer is the pressure sensor shell. The main materials are aluminum alloy, alloy steel and stainless steel.
Strain gauge: The strain gauge pressure is an important part of the sensor. Commonly used strain gauge base material adopts polymer film material. The strained material is usually high-purity constantan. The strain gauge is attached to the elastic body through dehydration. The elastic body is deformed by force. The strain gauge then deforms. Thereby changing the resistance value.
Measurement circuit: Transform the resistance change of the strain gauge into a millivolt signal output through the Wheatstone bridge.
Transmission cable: 4-core shielded cable with four wires of red, black, green and white. Red: Power +. Black: Power-. Green: signal +. White: Signal-.

Pressure Switch:
As the name suggests, a pressure switch is a switch. It’s just that this switch is the pressure set in advance. When the measured medium reaches this pressure level, the switch can automatically turn on or off. The pressure switch must be given a pressure value in advance. Then turn the switch on or off. They are used for simple control and are all digital outputs.
Pressure Sensor:
The pressure sensor can output not only analog signals but also digital signals. Digital signal processing is more convenient, and remote transmission is also possible. The pressure sensor is composed of a pressure sensitive element and a conversion circuit. Use the pressure of the measured medium to produce a small change in current or voltage output on the pressure sensitive element.

The main function of a pressure transmitter is to transmit pressure signals to electronic equipment. The pressure is then displayed on the computer. For example, the mechanical signal of water pressure is converted into an electronic signal such as voltage or current (usually 0-5V or 4-20mA). Pressure and voltage or current have a linear relationship. It is generally proportional, so the voltage or current output by the transmitter increases with increasing pressure.
A pressure transmitter is a sensor commonly used in industrial practice. It is widely used in various industrial automatic control environments. Involving water conservancy and hydropower, railway transportation, intelligent buildings, production control, aerospace, military industry, petrochemicals, oil wells, electric power, ships, machine tools, pipelines and many other industries. The pressure transmitter workshop must be in direct contact with the measured medium. Often run in high temperature, low temperature, corrosion, vibration, shock and other environments. Whether it works normally on the job site depends not only on the quality of the product. It also depends on optimized engineering design and reasonable model configuration. And proper installation and maintenance. Pressure transmitters are a key element in the fluid industry.
Pressure transmitters are mainly used in the following areas:
1.Petroleum, petrochemical, chemical industry, supporting with throttling devices. Provides accurate flow measurement and control. Measures pressure and level in pipes and tanks.
2.Electric power, city gas, and other companies. Places requiring high stability and high accuracy measurement.
3.Pulp and papermaking are used in places that require chemical-resistant liquids and corrosion-resistant liquids.
4. Steel, non-ferrous metals, ceramics, used in furnace pressure measurement and other places requiring high stability, high precision measurement and other places. It is used in places where stable measurement is required under strict control (temperature, humidity, etc.).
5. Machinery and shipbuilding, used to strictly control the place where high precision is required for stable measurement.
In general, the pressure transmitter is mainly used to measure the pressure of the medium and the liquid level.