Conditioning circuit of linear variable differential transformer (LVDT)

Abstract

The invention discloses a conditioning circuit of a linear variable differential transformer (LVDT). The conditioning circuit comprises a half-bridge position sensor, an analog-digital conversion circuit, a controller data processing unit, an upper computer, a sine wave generating circuit, an inverting circuit, an amplifying circuit, a channel selector switch, an absolute value circuit and a peak holding circuit, wherein the analog-digital conversion circuit is connected with the upper computer through the controller data processing unit; one path of the output end of the sine wave generating circuit is connected with the positive input end of the position sensor through the inverting circuit, and the other path of the output end of the sine wave generating circuit is connected with the positive input end of the position sensor; the output end of the position sensor is connected with the input end of the channel selector switch through the amplifying circuit; the output end of the channel selector switch is connected with the input end of the peak holding circuit through the input end and the output end of the absolute value circuit; and the output end of the peak holding circuit is connected with the input end of the analog-digital conversion circuit. The conditioning circuit consisting of discrete components has the advantages of low temperature excursion and low cost.

Description

technical field [0001] The invention belongs to a sensor conditioning circuit, in particular to a circuit capable of processing the output signal of an LVDT displacement sensor and converting it into a digital signal. Background technique [0002] LVDT displacement sensor is a sensor that converts the movement of a mandrel in a coil magnetic field into various electronic signals. The LVDT displacement sensor needs a sine wave signal input with a certain frequency and amplitude as an excitation, and outputs a sine wave signal with the same frequency and amplitude change, which is linearly proportional to the displacement of the displacement sensor's probe. [0003] figure 1 It is the electrical principle block diagram of the LVDT displacement sensor conditioning circuit in the prior art. The position sensor is connected with the upper computer through the AD698 conditioning circuit, the analog-to-digital conversion circuit, and the controller data processing unit. The AD698 ...

AI Technical Summary

Problems solved by technology

Although this conditioning circuit has high integration and simple structure, it will cause a certain temperature drift due to the heating of the AD698 chip itself; and the cost of the AD698 chip is relatively high, which is one of the reasons why the current LVDT displacement sensor conditioner is expensive

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