Summary:Smart sensor is based on sensor technology, the signal sent by the sensor signal processing. This paper mainly introduces the implementation of intelligent pressure sensor, which is divided into two parts: hardware and software. The hardware part mainly introduces the characteristics and implementation methods of each application device; the software part mainly introduces the compiling ideas of information processing.
Smart sensors are based on sensor technology and signal processing by the sensor. First, the signal is amplified by the chopper stabilization amplifier, and then the analog-to-digital conversion is performed by the A/D converter and then controlled by the microcontroller AT89C51, and finally displayed. Here, the smart pressure sensor studied is to display the pressure after the electrical signal output by the pressure sensor is processed, and the intelligence is further improved through the keyboard control.
With the continuous development of computer technology, information processing technology is also constantly improving. But as a sensor that provides information, its development lags behind the computer's information processing function. This has caused the automatic detection technology to be affected, and detection technology is an indispensable and important means for human beings to understand the world and transform technology. Based on the above factors, more and more scientific and technical workers attach great importance to the sensor technology, prompting the rapid development of sensor technology to meet the needs of information processing technology. The breakthrough is based on the level of testing technology. Piezoresistive diffusion silicon pressure sensors are widely used at low prices. The smart pressure sensors based on single-chip microcomputer technology are widely used because of their convenient use and accurate measurement. The core of the pressure sensor is the diffusion silicon resistance bridge. The smart pressure sensor uses single chip technology to collect data and signal processing and output the display results. The piezoresistive coefficient of diffused silicon is a function of temperature, so there is a sensitivity drift, and the factors affecting temperature are many: measurement environment changes, the effect of measuring the heat generated by the circuit, etc., so to get a more accurate pressure value The pressure sensor must be calibrated. The zero point of the pressure sensor has thermal drift, electrical drift and time drift. The measures to reduce the thermal zero drift of the pressure sensor are the resistance values ​​of the force sensitive resistors and the equality of their temperature coefficients.
This paper mainly introduces the implementation of intelligent pressure sensor, which is divided into two parts: hardware and software. The hardware part mainly introduces the characteristics and implementation methods of each application device; the software part mainly introduces the compiling ideas of information processing.
Chapter 1 Introduction Sensor technology occupies a very important position in the field of modern science and technology. It is a vantage point for people in the development of high and new technology in the 21st century. Sensor technology is considered as the key to the development of modern high technology in foreign developed countries. Since the 1980s, Japan has ranked sensor technology as the first priority for high salvage technology. The United States and other Western countries have also listed sensor basic knowledge as a key component of national science and technology and national defense technology development. At present, the world is facing a new technological revolution. The main basis of this revolution is information technology. The development of information technology has brought tremendous, extensive, and profound changes to all sectors and fields of the human society and the national economy. It is a powerful driving force for the development of human society today. It is also changing the production methods of traditional industries and bringing about the renewal and transformation of traditional industries and other emerging industries. In the field of military defense, aerospace, marine development, bioengineering, health care, commodity inspection, environmental protection, safety scope, and household appliances, almost every modern project can not be separated from sensor technology.
The collection of information refers to the acquisition of information that people need from nature, as well as during production or scientific experimentation. Information acquisition is achieved through sensor technology, so sensor detection technology is essentially information acquisition technology. Obviously, in the three major aspects of modern information technology, “acquisition†is the primary basis, there is no “acquired†information, communication “transmission†is “passive waterâ€, and computer “processing†is “ Without rice."
However, with the rapid development of computer technology, information processing technology is constantly updated and improved. However, as an element sensor providing information, its development lags behind the computer's information processing function. This affects the automatic detection technology and directly affects the further development of multiple technologies. Based on the above factors, more and more scientific and technical workers attach great importance to the sensor technology, prompting the rapid development of sensor technology to meet the needs of information processing technology.
The intelligent pressure sensor designed and researched is to display the pressure after processing the electrical signal output by the pressure sensor, and to make the intelligence more perfect through the keyboard control.
Chapter II Structure and Characteristics of Smart Sensors and Data Acquisition and Data Processing Section 1 Structure and Characteristics of Smart Sensors Figure 2-1 shows the structure of smart sensors.
Smart sensor features:
(!) Extends the measurement range and function, and can meet the measurement of parameters and various requirements of the measurement;
(2) Improved sensitivity and measurement accuracy, weak signal measurement, and various corrections and compensations; measurement data can be accessed;
(3) Improve the stability and possibility of measurement, eliminate external interference, and perform selective measurement to improve the performance of the sensor;
(4) It has self-diagnosis function, functions such as identifying fault location, identifying fault status, and functions difficult to implement with hardware;
(5) There can be multiple tree formats and digital communication interfaces.
Both intelligent sensors and sensor intelligence are sensors with detection and information processing capabilities.
§ Section 2 Data Acquisition and Data Processing for Smart Sensors Before the sensors are intelligent, their output signals must be preprocessed. Due to the large variety of detected signals, the output signal has analog quantity, digital quantity, and switch quantity. Most sensor output sensor output signals cannot be directly used as A/D conversion input quantity, and sensors must be passed through various pre-processing circuits. The output signal is converted into a uniform voltage signal or periodic signal.
The data acquisition sensor signal is processed and processed to become the point analog signal required by the A/D converter. The simulation of elegant digitization depends on the analog converter (A/D) which converts the input signal to digital by sampling, quantization, and coding. signal.
The data output signal of the data processing sensor is converted by the A/D converter. The obtained digital signal is generally not directly input to the microprocessor supply program, but must also be processed as required, such as scale conversion, nonlinear compensation, and temperature. Compensation, digital filtering, etc. These processes are also called software processing.
The data processing package works in the following areas;
(1) Data collection: collecting required information;
(2) Data conversion: converting the required information into a suitable method for the use of microprocessors;
(3) Data grouping: effective grouping according to relevant information;
(4) Data organization: organizing data or using other methods to arrange data for processing and error correction;
(5) Data calculation: Perform various arithmetic and logic operations to obtain further information;
(6) Data storage: save the original data and calculation results for later use;
(7) Data search: Provide useful information in a format as required, and then output the result according to user requirements.
Intelligent signal preprocessing, sampling cycle, A/D converter selection, and some compensation methods in data processing are not introduced here.
Chapter III Design of Intelligent Pressure Sensors According to the technical indicators proposed for smart sensors, the design process mainly includes overall structural design, sensitive component design, sensor process design, and software design. This paper only deals with the overall structural design of smart pressure sensors and Software design for introduction.
Structural design smart pressure sensor consists of semiconductor sensor, amplifier, transfer switch, double integral A/D converter, SCM, interface circuit, IEEE-488 standard interface, memory and some peripheral circuits.
As shown in Figure 3-1;
Software design The smart pressure sensor software composed of single chip microcomputer has control program, data processing program and auxiliary program.
One of the important features of the smart pressure sensor is multifunction. Generally, it uses two methods to execute: First, the user issues the selected function instruction through the keyboard; second, the automatic type, and the internal function control program coordinates the prepared data acquisition and The processing program works, or receives external signals through the IEEE-488 bus, and sends out control commands to the smart sensors. The smart sensors are guaranteed by self-calibration, tracking, over-limit alarm, output print, keyboard, display, A/D conversion, and other circuits and interfaces. The work can be carried out in an orderly manner according to the source program flow chart of Fig. 2-3; after the smart sensor is installed, calibration is required, the signal is converted into a digital code, stored in the EPROM, and finally an ideal output is given, as shown in Fig. 3 -3 shows;
This smart sensor can use the sealing technology of integrated circuits and sensors to integrate and connect silicon-powered devices with temperature sensing diodes and microcontrollers, A/D converters, and interface circuits to make the entire system The functions of program control, calculation, and processing automatically correct and compensate the test output signal, and can be stable in the environment where the ambient temperature changes over a long period of time.
Chapter IV Conclusion The smart pressure sensor is an intelligent instrument for detecting pressure. Its measurement is very precise and it is widely used in electronic weighing or business measurement. This design is to achieve the direct display of pressure through the system, and through the keyboard control to make the intelligence more perfect.
Smart sensors are based on sensor technology and signal processing by the sensor. First, the signal is amplified by the chopper stabilization amplifier, and then the analog-to-digital conversion is performed by the A/D converter and then controlled by the microcontroller AT89C51, and finally displayed. Here, the smart pressure sensor studied is to display the pressure after the electrical signal output by the pressure sensor is processed, and the intelligence is further improved through the keyboard control.
With the continuous development of computer technology, information processing technology is also constantly improving. But as a sensor that provides information, its development lags behind the computer's information processing function. This has caused the automatic detection technology to be affected, and detection technology is an indispensable and important means for human beings to understand the world and transform technology. Based on the above factors, more and more scientific and technical workers attach great importance to the sensor technology, prompting the rapid development of sensor technology to meet the needs of information processing technology. The breakthrough is based on the level of testing technology. Piezoresistive diffusion silicon pressure sensors are widely used at low prices. The smart pressure sensors based on single-chip microcomputer technology are widely used because of their convenient use and accurate measurement. The core of the pressure sensor is the diffusion silicon resistance bridge. The smart pressure sensor uses single chip technology to collect data and signal processing and output the display results. The piezoresistive coefficient of diffused silicon is a function of temperature, so there is a sensitivity drift, and the factors affecting temperature are many: measurement environment changes, the effect of measuring the heat generated by the circuit, etc., so to get a more accurate pressure value The pressure sensor must be calibrated. The zero point of the pressure sensor has thermal drift, electrical drift and time drift. The measures to reduce the thermal zero drift of the pressure sensor are the resistance values ​​of the force sensitive resistors and the equality of their temperature coefficients.
This paper mainly introduces the implementation of intelligent pressure sensor, which is divided into two parts: hardware and software. The hardware part mainly introduces the characteristics and implementation methods of each application device; the software part mainly introduces the compiling ideas of information processing.
Chapter 1 Introduction Sensor technology occupies a very important position in the field of modern science and technology. It is a vantage point for people in the development of high and new technology in the 21st century. Sensor technology is considered as the key to the development of modern high technology in foreign developed countries. Since the 1980s, Japan has ranked sensor technology as the first priority for high salvage technology. The United States and other Western countries have also listed sensor basic knowledge as a key component of national science and technology and national defense technology development. At present, the world is facing a new technological revolution. The main basis of this revolution is information technology. The development of information technology has brought tremendous, extensive, and profound changes to all sectors and fields of the human society and the national economy. It is a powerful driving force for the development of human society today. It is also changing the production methods of traditional industries and bringing about the renewal and transformation of traditional industries and other emerging industries. In the field of military defense, aerospace, marine development, bioengineering, health care, commodity inspection, environmental protection, safety scope, and household appliances, almost every modern project can not be separated from sensor technology.
The collection of information refers to the acquisition of information that people need from nature, as well as during production or scientific experimentation. Information acquisition is achieved through sensor technology, so sensor detection technology is essentially information acquisition technology. Obviously, in the three major aspects of modern information technology, “acquisition†is the primary basis, there is no “acquired†information, communication “transmission†is “passive waterâ€, and computer “processing†is “ Without rice."
However, with the rapid development of computer technology, information processing technology is constantly updated and improved. However, as an element sensor providing information, its development lags behind the computer's information processing function. This affects the automatic detection technology and directly affects the further development of multiple technologies. Based on the above factors, more and more scientific and technical workers attach great importance to the sensor technology, prompting the rapid development of sensor technology to meet the needs of information processing technology.
The intelligent pressure sensor designed and researched is to display the pressure after processing the electrical signal output by the pressure sensor, and to make the intelligence more perfect through the keyboard control.
Chapter II Structure and Characteristics of Smart Sensors and Data Acquisition and Data Processing Section 1 Structure and Characteristics of Smart Sensors Figure 2-1 shows the structure of smart sensors.
Figure 2-1
Smart sensor features:
(!) Extends the measurement range and function, and can meet the measurement of parameters and various requirements of the measurement;
(2) Improved sensitivity and measurement accuracy, weak signal measurement, and various corrections and compensations; measurement data can be accessed;
(3) Improve the stability and possibility of measurement, eliminate external interference, and perform selective measurement to improve the performance of the sensor;
(4) It has self-diagnosis function, functions such as identifying fault location, identifying fault status, and functions difficult to implement with hardware;
(5) There can be multiple tree formats and digital communication interfaces.
Both intelligent sensors and sensor intelligence are sensors with detection and information processing capabilities.
§ Section 2 Data Acquisition and Data Processing for Smart Sensors Before the sensors are intelligent, their output signals must be preprocessed. Due to the large variety of detected signals, the output signal has analog quantity, digital quantity, and switch quantity. Most sensor output sensor output signals cannot be directly used as A/D conversion input quantity, and sensors must be passed through various pre-processing circuits. The output signal is converted into a uniform voltage signal or periodic signal.
The data acquisition sensor signal is processed and processed to become the point analog signal required by the A/D converter. The simulation of elegant digitization depends on the analog converter (A/D) which converts the input signal to digital by sampling, quantization, and coding. signal.
The data output signal of the data processing sensor is converted by the A/D converter. The obtained digital signal is generally not directly input to the microprocessor supply program, but must also be processed as required, such as scale conversion, nonlinear compensation, and temperature. Compensation, digital filtering, etc. These processes are also called software processing.
The data processing package works in the following areas;
(1) Data collection: collecting required information;
(2) Data conversion: converting the required information into a suitable method for the use of microprocessors;
(3) Data grouping: effective grouping according to relevant information;
(4) Data organization: organizing data or using other methods to arrange data for processing and error correction;
(5) Data calculation: Perform various arithmetic and logic operations to obtain further information;
(6) Data storage: save the original data and calculation results for later use;
(7) Data search: Provide useful information in a format as required, and then output the result according to user requirements.
Intelligent signal preprocessing, sampling cycle, A/D converter selection, and some compensation methods in data processing are not introduced here.
Chapter III Design of Intelligent Pressure Sensors According to the technical indicators proposed for smart sensors, the design process mainly includes overall structural design, sensitive component design, sensor process design, and software design. This paper only deals with the overall structural design of smart pressure sensors and Software design for introduction.
Structural design smart pressure sensor consists of semiconductor sensor, amplifier, transfer switch, double integral A/D converter, SCM, interface circuit, IEEE-488 standard interface, memory and some peripheral circuits.
As shown in Figure 3-1;
Silicon pressure sensor circuit diagram
Figure 3-1 block diagram of smart pressure sensor
Software design The smart pressure sensor software composed of single chip microcomputer has control program, data processing program and auxiliary program.
One of the important features of the smart pressure sensor is multifunction. Generally, it uses two methods to execute: First, the user issues the selected function instruction through the keyboard; second, the automatic type, and the internal function control program coordinates the prepared data acquisition and The processing program works, or receives external signals through the IEEE-488 bus, and sends out control commands to the smart sensors. The smart sensors are guaranteed by self-calibration, tracking, over-limit alarm, output print, keyboard, display, A/D conversion, and other circuits and interfaces. The work can be carried out in an orderly manner according to the source program flow chart of Fig. 2-3; after the smart sensor is installed, calibration is required, the signal is converted into a digital code, stored in the EPROM, and finally an ideal output is given, as shown in Fig. 3 -3 shows;
Figure 3-4 smart sensor source program flow chart
Figure 3-4 intelligent pressure sensor correction, display flow chart
This smart sensor can use the sealing technology of integrated circuits and sensors to integrate and connect silicon-powered devices with temperature sensing diodes and microcontrollers, A/D converters, and interface circuits to make the entire system The functions of program control, calculation, and processing automatically correct and compensate the test output signal, and can be stable in the environment where the ambient temperature changes over a long period of time.
Chapter IV Conclusion The smart pressure sensor is an intelligent instrument for detecting pressure. Its measurement is very precise and it is widely used in electronic weighing or business measurement. This design is to achieve the direct display of pressure through the system, and through the keyboard control to make the intelligence more perfect.
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