At present, almost all pull ropes in the world Displacement sensor Series products, no matter current, voltage, resistance type output products, all use multi turn potentiometer as the core measuring element. However, due to the manufacturing process, the general linear error of multi turn potentiometer is only 0.25% FS, and even the linear error of special process is only 0.15%, but the price is very expensive, which limits its wide application.
The pulling rope displacement sensor is to use the wire wheel which is installed in the same axis with the multi turn potentiometer. According to the rotation of the wire wheel, the pulling rope is evenly distributed around the wire wheel, and the effective stroke is 3.1415926 times of the diameter. At the same time, the potentiometer outputs a data. Because the linear accuracy of the potentiometer is limited, the linear accuracy of the wire rope displacement sensor can not exceed that of the potentiometer.
Brsen corrects the error of the cable displacement sensor through chip processing. The error can be measured and even recorded by the whole sensor. For the same type of potentiometer, through a large number of repeated measurements, the actual output value of the sampling point and its corresponding theoretical accurate value are stored in the database. When the displacement sensor outputs, the analog signal of potentiometer is converted into digital signal, and the digital chip finds the exact value corresponding to the value by searching the database and outputs it. For example, if the potentiometer output 1.005v in the database corresponds to the precise value 1V, then when the potentiometer outputs 1.005v, the chip can find the corresponding accurate value 1V in the database and output. If the output value does not exist in the database, then the output value can not be obtained by interpolation. The number of sampling points is related to the number of digital signals. If the digital signal is 12 bits, then the number of sampling points is 4096 (the 12th power of 2). Through the digital processing chip, the actual measured data can be linearized, and then transformed to output various kinds of signals with high linear accuracy, including voltage, current analog signals and digital signals.