The concept of detection system is the product of the development of sensing technology to a certain stage. The detection system is an organic combination of sensors, measuring instruments, conversion devices, etc.
In engineering practice, sensors and multiple measuring instruments need to be organically combined to form a whole to complete signal detection, thus forming a detection system. With the continuous development of computer technology and information processing technology, the content of the detection system has been continuously enriched. In the modern production process, the detection of process parameters is carried out automatically, that is, the detection task is automatically completed by the detection system, so it is necessary to study and master the composition and principle of the detection system.
The sensor in the system is a device or device that senses the measured size and outputs the corresponding usable output signal. The data transmission link is used to transmit data. When several functional links of the detection system are separated independently, data must be transmitted from one place to another. The data transmission link is to complete this transmission function. 
The data processing link is to process and transform the output signal of the sensor. If the signal is amplified, calculated, filtered, linearized, digital-to-analog (D / A) or analog-to-digital (D / A) conversion, converted to another parameter signal or some standardized unified signal, etc., to make it output It is easy to display and record, and can also be connected with a computer system in order to carry out information processing on the measurement signal or used for automatic control of the system. The data display link will be accepted by the measurement information in order to achieve the purpose of monitoring, control or analysis. The measurement results can be displayed by analog or digital, and can be automatically recorded by the recording device or printed by the printer.
The purpose of the measurement is to obtain the measured true value through measurement. However, in the actual measurement process, due to various reasons, for example, the performance of the sensor itself is not ideal, the measurement method is imperfect, affected by external interference and human negligence, etc., will cause the measured value of the measured parameter to be inconsistent with the true value, and the two are inconsistent The degree is expressed by measurement error.
The error is the difference between the measured value and the true value, which reflects the accuracy of the measurement.
With the development of science and technology, people have higher and higher requirements for measurement accuracy. It can be said that the value of measurement work depends on the accuracy of measurement. When the measurement error exceeds a certain limit, the measurement work and the measurement results are meaningless and may even cause harm to the work. Therefore, the analysis and control of measurement errors has become an important aspect to measure the level of measurement technology and even the level of science and technology. However, due to the inevitability and universality of the error, people can only control the error as small as possible, but not completely eliminate it.
On the other hand, the reliability of the measurement is also crucial. Different occasions and different systems have different requirements for the reliability of the measurement results. For example, when the measured value is used as a control signal, attention should be paid to the stability and reliability of the measurement. Therefore, the performance indexes such as the accuracy and reliability of the measurement must be related to and adapted to the specific measurement purpose and requirements. In this way, the function and characteristics of the sensor can be better played!
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