Displacement sensor conditioning system based on LVDT

Abstract

The utility model discloses a conditioning circuit system based on an LVDT displacement sensor. The conditioning circuit system comprises an RC bridge oscillation circuit, an LVDT displacement sensor, a first channel circuit, a second channel circuit, a data processing circuit and an amplification circuit. The LVDT displacement sensor conditioning circuit provided by the utility model can effectively suppress noise interference and increase the amplitude of a detection signal so as to obtain a stable and effective output signal, and the stability is high.

Description

Technical Field

[0001] The utility model relates to the field of differential transformers, in particular to a conditioning system and method based on an LVDT displacement sensor. Background Art

[0002] LVDT (Linear Variable Differential Transformer) displacement sensor is a precision measuring device widely used in industry and scientific research. The core components of LVDT displacement sensor include a primary coil, two secondary coils and a movable iron core. These three coils are all wound on a common coil frame. When the iron core moves in the coil, the secondary coil generates an induced electromotive force due to the change in the mutual inductance between the primary coil and the secondary coil. The difference in the induced electromotive force generated by the two secondary coils is linearly related to the displacement of the iron core, thereby realizing the conversion of the displacement to a voltage signal. It is widely used in various industries of the national economy such as aerospace, construction, machinery, railways, coal, textiles, and chemicals to measure the elongation, vibration frequency, thickness and other precise data of objects. In the case of complex external noise environment, the existing application of LVDT displacement sensor conditioning circuit will affect the accuracy of measurement. How to avoid the influence of noise on the LVDT conditioning circuit has become a technical problem that needs to be solved urgently. Utility Model Content

[0003] According to the above-mentioned technical problem of how to avoid the influence of noise on the LVDT conditioning circuit, a conditioning circuit system based on an LVDT displacement sensor is provided.

[0004] The technical means adopted by the utility model are as follows:

[0005] A conditioning circuit system based on an LVDT displacement sensor, comprising:

[0006] RC bridge oscillation circuit, LVDT displacement sensor, first channel circuit, second channel circuit, data processing circuit and amplification circuit;

[0007] The RC bridge oscillation circuit is used to generate an excitation signal and output a frequency-adjustable sinusoidal wave signal;

[0008] The primary coil of the LVDT displacement sensor is connected to the output end of the RC bridge oscillation circuit, and the signal generated by the secondary coil of the LVDT sensor is sent to the first channel circuit for processing;

[0009] The first channel circuit includes a front signal processing circuit and a first modulation and demodulation circuit;

[0010] The second channel circuit includes a phase shift circuit and a second modulation and demodulation circuit, and an input end thereof is used to receive an excitation signal generated by the RC bridge oscillation circuit;

[0011] The input end of the data processing circuit is connected to the output ends of the first channel circuit and the second channel circuit; the output end of the data processing circuit is connected to the input end of the amplifier circuit.

[0012] Furthermore, the RC bridge oscillation circuit is connected to the primary coil of the LVDT displacement sensor, the first modulation and demodulation circuit and the phase shift circuit; the excitation signal in the RC bridge oscillation circuit is respectively sent to the primary coil of the LVDT displacement sensor, the first modulation and demodulation circuit and the phase shift circuit.

[0013] Furthermore, the LVDT displacement sensor is connected in a five-wire system, and the signal generated by the secondary coil is transmitted to the front signal processing circuit to filter out noise signals.

[0014] Furthermore, the input end of the phase shift circuit is connected to the output end of the RC bridge oscillator circuit to shift the sine wave by 90 degrees.

[0015] Furthermore, the input end of the second modulation and demodulation circuit is respectively connected to the output ends of the pre-signal processing circuit and the phase shift circuit in the first channel circuit.

[0016] Furthermore, the input end of the data processing circuit is connected to the output end of the first modulation and demodulation circuit and the output end of the second modulation and demodulation circuit, and the output end of the data processing circuit is connected to the input end of the amplifier circuit. Vector operations are performed on the two signals and amplified to obtain a voltage signal proportional to the displacement.

[0017] Compared with the prior art, the utility model has the following advantages:

[0018] The utility model provides an LVDT measurement circuit, in which an RC bridge oscillation circuit outputs a frequency-adjustable sinusoidal wave signal as an excitation signal to a signal conditioning circuit. By processing the dual-channel output signals, the influence of external interference signals on the measured signal can be effectively suppressed, thereby greatly improving the accuracy of signal extraction. The amplitude and phase information of the measured signal can be extracted with high precision, which is beneficial to solving the error caused by phase shift. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 The schematic diagram provided for the utility model;

[0021] Figure 2 The circuit principle diagram of the RC bridge oscillator circuit provided by the utility model;

[0022] Figure 3 A schematic diagram of the structure of the LVDT sensor provided by the utility model;

[0023] Figure 4 A schematic diagram of a pre-signal processing circuit provided by the utility model;

[0024] Figure 5 A schematic diagram of a first modulation and demodulation circuit and a second modulation and demodulation circuit provided by the utility model;

[0025] Figure 6 A circuit schematic diagram of a phase shift circuit provided by the utility model;

[0026] Figure 7 A circuit schematic diagram of a data processing circuit provided by the utility model;

[0027] Figure 8 The utility model provides a circuit schematic diagram of the amplifier circuit. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the utility model described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0030] The utility model aims to provide a signal conditioning circuit system based on an LVDT displacement sensor, which can suppress the influence of external interference signals on the signal to be measured, thereby greatly improving the accuracy of signal extraction.

[0031] The utility model will be described in further detail below with reference to the accompanying drawings:

[0032] refer to Figure 1 The LVDT signal conditioning system of the utility model includes: an RC bridge oscillation circuit, an LVDT displacement sensor, a first channel circuit, a second channel circuit, a data processing circuit and an amplification circuit.

[0033] It should be noted that the output end of the RC bridge oscillation circuit is connected to the primary coil of the LVDT displacement sensor; the first channel circuit includes a pre-signal processing circuit and a first modulation and demodulation circuit; the input end of the pre-signal processing circuit is connected to the secondary coil of the LVDT displacement sensor, and its output end is connected to the input end of the first modulation and demodulation circuit; the input end of the first modulation and demodulation circuit is also connected to the output end of the RC bridge oscillation circuit, and its output end is connected to the input end of the data processing circuit; the second channel circuit includes a phase shifting circuit and a second modulation and demodulation circuit; the input end of the phase shifting circuit is connected to the output end of the RC bridge oscillation circuit, and its output end is connected to the input end of the second modulation and demodulation circuit; the input end of the second modulation and demodulation circuit is connected to the output end of the pre-signal processing circuit in the first channel circuit; the input end of the data processing circuit is connected to the output ends of the first modulation and demodulation circuit and the second modulation and demodulation circuit; the output end of the data processing circuit is connected to the input end of the amplifier circuit.

[0034] As a preferred embodiment, in the present application, the RC bridge oscillator circuit is connected to the primary coil of the LVDT displacement sensor, the first modulation and demodulation circuit and the phase shift circuit; the excitation signal in the RC bridge oscillator circuit is respectively sent to the primary coil of the LVDT displacement sensor, the first modulation and demodulation circuit and the phase shift circuit.

[0035] Preferably, the LVDT displacement sensor is connected in a five-wire system, and the signal generated by the secondary coil is transmitted to a front-end signal processing circuit to filter out noise signals.

[0036] In the present application, the input end of the phase shift circuit is connected to the output end of the RC bridge oscillator circuit to shift the sine wave by 90 degrees.

[0037] As a preferred embodiment, in the present application, the input end of the second modulation and demodulation circuit is respectively connected to the output end of the pre-signal processing circuit and the phase shift circuit in the first channel circuit. The input end of the data processing circuit is connected to the output end of the first modulation and demodulation circuit and the second modulation and demodulation circuit, and the output end of the data processing circuit is connected to the input end of the amplifier circuit, and vector operations are performed on the two signals and amplified to obtain a voltage signal proportional to the displacement.

[0038] The serial numbers of the above embodiments of the utility model are only for description and do not represent the advantages and disadvantages of the embodiments. In the above embodiments of the utility model, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A conditioning system based on LVDT displacement sensor, characterized in that: include: RC bridge oscillation circuit, LVDT displacement sensor, first channel circuit, second channel circuit, data processing circuit and amplification circuit; The RC bridge oscillator circuit is used to generate an excitation signal and output a frequency-adjustable sinusoidal wave signal; the output end of the RC bridge oscillator circuit is connected to the primary coil of the LVDT displacement sensor; The primary coil of the LVDT displacement sensor is connected to the output end of the RC bridge oscillation circuit, and the signal generated by the secondary coil of the LVDT displacement sensor is sent to the first channel circuit for processing; The first channel circuit includes: a front signal processing circuit and a first modulation and demodulation circuit; The second channel circuit comprises: a phase shift circuit and a second modulation and demodulation circuit, and the input end of the second channel circuit is used to receive the excitation signal generated by the RC bridge oscillation circuit; The input end of the data processing circuit is connected to the output ends of the first channel circuit and the second channel circuit; the output end of the data processing circuit is connected to the input end of the amplifier circuit.

2. The LVDT displacement sensor conditioning system according to claim 1, characterized in that: The RC bridge oscillation circuit is connected to the primary coil of the LVDT displacement sensor, the first modulation and demodulation circuit and the phase shift circuit; the excitation signal in the RC bridge oscillation circuit is respectively sent to the primary coil of the LVDT displacement sensor, the first modulation and demodulation circuit and the phase shift circuit.

3. The LVDT displacement sensor conditioning system according to claim 1, characterized in that: The LVDT displacement sensor is connected in a five-wire system, and the signal generated by the secondary coil is transmitted to the front signal processing circuit to filter out the noise signal.

4. The LVDT displacement sensor conditioning system according to claim 1, characterized in that: The input end of the phase shift circuit is connected to the output end of the RC bridge oscillator circuit to shift the sine wave by 90 degrees.

5. The LVDT displacement sensor conditioning system according to claim 1, characterized in that: The input end of the second modulation and demodulation circuit is respectively connected to the output ends of the pre-signal processing circuit and the phase shift circuit in the first channel circuit.

6. The LVDT displacement sensor conditioning system according to claim 1, characterized in that: The input end of the data processing circuit is connected to the output end of the first modulation and demodulation circuit and the output end of the second modulation and demodulation circuit, and the output end of the data processing circuit is connected to the input end of the amplifier circuit. Vector operations are performed on the two signals and amplified to obtain a voltage signal proportional to the displacement.

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