High-precision sensors are instructions that convert physical quantities into other intuitive and expressible physical quantities through circuits. The editor will introduce the characteristics of high-precision sensors to you through this article.
1. Sensor concept
A sensor is a detection device that can detect the measured information and convert the perceptible information into electrical signals or other necessary forms of information output according to certain rules. Meet the requirements of information transmission, processing, storage, display, recording and control. This is the first step towards automatic detection and automatic control.
2. Introduction of sensor characteristics
1. Static characteristics: a static input signal that represents the relationship between output and input. At this time, the input and output have nothing to do with time, so the static characteristics can be described by the algebraic equation without time variable or the input as the abscissa and the characteristic curve drawn by the ordinate. The main parameters of static characteristics are linearity, sensitivity, resolution, delay and so on.
2. Dynamic characteristics: refers to the output characteristics when the input changes. In practice, dynamic characteristics are usually expressed as the response to a specific standard input signal. This is because the sensor knows that it is easy to obtain the response to the standard input signal experimentally, and there is a certain relationship between the response to the standard input signal and the response to the random input signal, so the former can estimate the latter. Commonly used standard input signals have both phase and sinusoidal signals, so the dynamic characteristics of high-precision sensors are often also displayed as phase and frequency responses.
3. Linearity: Generally speaking, the actual static characteristic output of high-precision sensors is a curve, not a straight line. In actual work, in order to provide the meter with a uniform scale reading, the fitting line that approximates the actual characteristic curve and linearity (non-linear error) is this approximate performance indicator.
There are many ways to fit straight lines. Use the theoretical line connecting the zero input and full-scale output points as the fitting line, or use the theoretical line that is the smallest sum of the squares of deviations from each point on the characteristic curve as the fitting line. This fitted line is referred to as the fitted line to the small squares.
4. Hysteresis characteristic: It characterizes the degree to which the sensor outputs between forward (increase in input) and reverse (increase in input) strokes. The degree of inconsistency between the input characteristic curves, generally the difference MAX between the two curves and the full-scale output F is expressed as a percentage of s. The delay may be caused by energy absorption by the sensor's internal components.
5. Sensitivity: Sensitivity refers to the ratio of the output change y to the input change x when the sensor is working normally. The slope of the output input characteristic curve. If there is a linear relationship between the sensor's output and input, the sensitivity S is constant. Otherwise, it will vary based on the input amount.