Principle and dynamics of wireless pressure sensors
Published time: 2019-12-20 10:28:06
The wireless pressure sensor is a low-power battery-powered (also optional external power supply) wireless digital output pressure sensor, optional GPRS, LORa, NB-iot and other wireless communication protocols. The wireless pressure sensor can display pressure and upload data in real time, and has the characteristics of high precision, convenient use, and good stability. The wireless pressure sensor has a built-in MCU and low-power design to realize the wireless transmission function of uploading the pipeline pressure in the field to the cloud. Suitable for intelligent fire protection in fire protection pipelines, fire end, fire pump room, smart city, petrochemical industry and remote areas, etc., which require unattended and remote monitoring.
Principle of wireless pressure sensor
The digital pressure sensor adopts the piezoresistive strain principle, and its core component resistance strain gauge is a sensitive device that converts the strain change on the device under test into an electrical signal. It is one of the main components of the sensor. The most widely used resistance strain gauges are metal resistance strain gauges and semiconductor strain gauges. The metal resistance strain gauge has two kinds of filament strain gauges and metal foil strain gauges. Usually, the strain gauge is tightly bonded to the mechanical strain matrix by a special adhesive. When the stress changes due to the force of the substrate, the strain gauges are also deformed together, so that the resistance of the strain gauge is changed, thereby The voltage applied to the resistor changes. Such strain gauges typically have a small change in resistance when subjected to force. Typically, such strain gauges form a strain bridge that converts impedance changes into digital signals.
Wireless pressure sensor dynamics
The so-called dynamic characteristic refers to the characteristic of the output of the sensor when the input changes. In practice, the dynamic characteristics of a sensor are often expressed in terms of its response to certain standard input signals. This is because the sensor's response to a standard input signal is easily experimentally determined, and its relationship to the standard input signal has a certain relationship with its response to any input signal, and it is often known that the former can presume the latter. Commonly used standard input signals are step signals and sinusoidal signals, so the dynamic characteristics of the sensor are also commonly expressed by step response and frequency response.
Linearity of wireless pressure sensor
Typically, the actual static characteristic output of the sensor is a bar curve rather than a straight line. In actual work, in order to make the meter have a uniform scale reading, a fitting straight line is commonly used to represent the actual characteristic curve, and the linearity (non-linearity error) is a performance index of this approximation.
There are several ways to select a fitted line. For example, the theoretical straight line connecting the zero input and the full-scale output point is used as the fitted straight line; or the theoretical straight line with the smallest square of the deviation from each point on the characteristic curve is used as the fitted straight line, and the fitted straight line is called the least squares method. Straight line.Tag: sensors