The precision of displacement sensors is a major factor affecting the displacement measurement and position positioning accuracy of automated equipment. The actual measurement errors of mechanical equipment include systematic errors and random errors. The more times of measurement, the error value may show a normal distribution on both sides around a certain average value. The deviation between the average value and the target measurement value can reflect the magnitude of the systematic error of the automated equipment, and the discrete bandwidth reflects the magnitude of the random error of the automated equipment. In field applications, some necessary measures can be taken to reduce the systematic error of displacement sensors and improve the control precision of equipment.

1. Strengthening the scientific design of sensor structure and circuit, strictly controlling the technological process, and standardizing the installation and use of sensors can reduce the systematic error of displacement sensors. Electrical compensation or software compensation methods can also be used to reduce the comprehensive error in the system measurement process. Error compensation is to artificially create a data equal to and opposite in direction to the measurement error to correct the systematic error and improve the control precision of equipment. Because the systematic error is always greater than the random error, the compensation method can achieve remarkable results.

2. The electrical compensation method is to set up corresponding gap compensation circuits and pitch compensation circuits in the control system to achieve the purpose of error compensation. Commonly used circuit compensation methods include: analog circuits and digital circuits, such as: diode array square root extractors, digital control segmented correction and nonlinear A/D conversion of various logarithmic, exponential, and trigonometric function operational amplifiers.

3. The software compensation method is to use the computing function of a computer to assist in compensating and eliminating measurement errors, which can include pitch cumulative error compensation, reverse clearance error compensation, and thermal deformation error compensation. It can also compensate for precision errors caused by wear and other reasons according to the data calculated by regular measurements. Because of its strong flexibility and freely settable compensation amount, the software compensation method is most widely used in industrial automation measurement and control systems.

4. Commonly used software compensation methods include calculation method and look-up table method. When there is a definite proportional relationship (or formula) between the sensor output electrical signal and the measured parameter, the calculation method can be used to perform nonlinear compensation on the measurement data of the automation system. That is, in the software, do a good job in programming the formula between the sensor output signal and the measured parameter. After sampling, filtering, and signal conversion, the measured parameter directly enters the computer program for calculation, and the calculated data is the output data processed by the compensation method. In automation measurement and control systems, the calculation of some parameters is relatively cumbersome and complex, involving advanced mathematical operations such as exponents, logarithms, trigonometric functions, integrals, or differentials. Writing programs in assembly language is relatively complex, and some cannot establish corresponding mathematical models. To solve such problems, the look-up table method can be used. The look-up table method is to first calculate the detection value and the detected value according to a known formula, or measure the result in advance by a measurement method, and then arrange the data into a table according to a certain method and store it in a memory unit. Later, the microprocessor can find out the measured result according to the size of the detection value. The look-up table method can perform functions such as data compensation, calculation, and conversion. The program is simple and the execution speed is fast, but it occupies a large amount of memory.

The performance of sensors usually changes with temperature. To reduce the influence of temperature drift on sensor precision, certain temperature compensation technologies are often adopted. Common ones are: self-compensation method, parallel compensation method, and feedback compensation method. The self-compensation technology is to use the temperature characteristics of the sensor's own components to offset the influence of ambient temperature on the sensor performance; the parallel compensation technology is to parallel a temperature compensation circuit on the main measuring component of the displacement sensor so that the sensor output signal does not change with temperature; the feedback compensation technology is to use the negative feedback principle to keep the sensor characteristics unaffected by changes in ambient temperature.