CN202393342U - Gap sensor - Google Patents
Gap sensor Download PDFInfo
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- CN202393342U CN202393342U CN2011204722530U CN201120472253U CN202393342U CN 202393342 U CN202393342 U CN 202393342U CN 2011204722530 U CN2011204722530 U CN 2011204722530U CN 201120472253 U CN201120472253 U CN 201120472253U CN 202393342 U CN202393342 U CN 202393342U
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Abstract
The utility model provides a gap sensor which includes a resonance circuit which is formed by connecting a detection coil with a capacitor in parallel, a differential excitation circuit which is connected with the two terminals of the resonance circuit, a synchronous demodulation circuit which is connected with the positive and negative terminals of the detection coil, an A/D converting circuit which is connected with the synchronous demodulation circuit, and a main control circuit which is provided with an RS485 interface. The main control circuit is connected with and controls the A/D converting circuit. A differential excitation signal is formed on the two terminals of the detection coil, so a detection signal on the detection coil can be transmitted stably without distortion, and consequently the capability of resisting the external environment interferences is greatly improved. The synchronous demodulation circuit can detect a peak-to-peak value of the detection signal, and a demodulated signal can be digitalized via the A/D converting circuit, and a digitalized decoding signal can be used as a memory address of the nonlinear correction data stored in an FPGA chip, and a corresponding gap value can be found. The gap value is output via the RS485 interface to form the digitalized signal transmission and control.
Description
Technical field
The utility model relates to the sensing detection technical field, is specifically related to a kind of gap sensor that uses in the levitation gap measurement of magnetic suspension train.
Background technology
Eddy current sensor can staticly be measured the distance of tested metallic conductor apart from detecting head surface with dynamically noncontact, high linearity, high resolution ground.Eddy displacement sensor can accurately be measured static and dynamic relative displacement variation between measured body (must be metallic conductor) and the probe end face, and it is a kind of non-contacting linearization metering outfit.Eddy displacement sensor is widely used in testing in the manufacturing, the Equipment Inspection of industrial basic research, precision equipment.At present, eddy displacement sensor is mainly used in the motion trace data of machinery that machinery and the reciprocating of high speed rotating are measured in research, and the research of vibration etc.Eddy displacement sensor particularly to non-contacting high precision vibration, displacement signal, can collect the multiple parameter of orbiting motions such as vibration, rotation continuously exactly in analysis to measure.Therefore, the sensing precision for eddy displacement sensor has very high requirement.
In to existing eddy displacement sensor research and practice process; The inventor of the utility model finds: because magnetic-levitation train mainly suspends by electromagnetic force; The electromagnetism intensity maximum possible reaches 10,000 Gausses; Sensor is worked under this environment, requires to have the ability of very high anti-electromagnetic interference (EMI), and not strong for the electromagnetism antijamming capability in the existing eddy current sensor; The eddy current sensor of especially autoexcitation formula receives the interference of extraneous forceful electric power magnetic environment easily; Cause the detection signal transmission unstable, finally cause the testing result distortion, therefore how avoiding external environment is the problem that prior art faces to the interference of detection signal and stable, the undistorted transmission of realization detection signal.
The utility model content
The utility model provides a kind of gap sensor, can address the above problem.
The utility model provides a kind of gap sensor, comprises the resonant tank that is composed in parallel by magnetic test coil and electric capacity; Be connected in the difference exciting circuit at resonant tank two ends; Be connected in the synchronous demodulation circuit at the positive and negative two ends of magnetic test coil; Be connected in the A/D change-over circuit of synchronous demodulation circuit; And governor circuit with RS485 interface; Said governor circuit connects and control A/D change-over circuit.
Technique scheme can be found out; Because the utility model embodiment difference exciting circuit forms the difference pumping signal at the magnetic test coil two ends; Make that so just detection signal on the magnetic test coil can be stablized, the distortionless transmission, the ability of opposing external environmental interference is increased dramatically; Synchronous demodulation circuit can detect the peak-to-peak value of detection signal; And process A/D change-over circuit is with the restituted signal digitizing; And with the digitizing decoded signal as the memory access address of the non-linear correction data of access in the fpga chip; Find corresponding gap width, this gap width forms digitized signal transmission and control through the output of RS485 interface.
Description of drawings
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art; To do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below; Obviously, the accompanying drawing in describing below only is some embodiment of the utility model, for those of ordinary skills; Under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the one-piece construction figure of the utility model embodiment intermediate gap sensor;
Fig. 2 is the circuit theory diagrams of the difference exciting circuit of the utility model embodiment intermediate gap sensor;
Fig. 3 is the circuit theory diagrams of the synchronous demodulation circuit of the utility model embodiment intermediate gap sensor.
Embodiment
To combine the accompanying drawing among the utility model embodiment below, the technical scheme among the utility model embodiment is carried out clear, intactly description, obviously, described embodiment only is the utility model part embodiment, rather than whole embodiment.Based on the embodiment in the utility model, those of ordinary skills are not making all other embodiment that obtained under the creative work prerequisite, all belong to the scope of the utility model protection.
Embodiment:
As shown in Figure 1, the utility model provides a kind of gap sensor, comprises the resonant tank that is composed in parallel by magnetic test coil L1 and capacitor C 3; Be connected in the difference exciting circuit at resonant tank two ends; Be connected in the synchronous demodulation circuit at the positive and negative two ends of magnetic test coil; Be connected in the A/D change-over circuit of synchronous demodulation circuit; And governor circuit with RS485 interface; Said governor circuit connects and control A/D change-over circuit.
Particularly, when gap to be measured changes, because vortex induction; Meeting generation electric current on the magnetic test coil L1 changes, thereby on resonant tank, produces oscillating voltage, and is connected in the two ends of difference exciting circuit output differential signal to the resonant tank at resonant tank two ends; Be magnetic test coil L1 and two parallelly connected points of capacitor C 3,, and the difference pumping signal be transferred to synchronous demodulation circuit so the positive and negative terminal of magnetic test coil L1 has just formed the difference pumping signal; Through after the demodulation of synchronous demodulation circuit; Detection signal just becomes restituted signal, but the restituted signal of this moment belongs to simulating signal, thereby the restituted signal of simulation is delivered to the A/D change-over circuit and carries out digitizing; Then digitized restituted signal is transported to governor circuit; Governor circuit adopts fpga chip among the utility model embodiment, and FPGA is connected with the RS485 interface, and the memory module in FPGA has the memory access that is used for the memory gap value; Therefore; Digitized restituted signal is with the memory access address of its voltage digital amount as correspondence, thereby makes fpga chip to transfer the gap width in this memory access address space through the voltage digital amount of restituted signal, and then exports this gap width the processing terminal of pick-up unit to through the RS485 interface.
Specifically as shown in Figure 2; Said difference exciting circuit comprises MIC4428 chip, capacitor C 1, capacitor C 2, resistance R 1 and resistance R 2; Two output terminals of MIC4428 chip connect resistance R 1, resistance R 2 respectively; Resistance R 1 is connected with capacitor C 1, and resistance R 2 is connected with capacitor C 2, and capacitor C 1 and capacitor C 2 are connected respectively to the two ends of resonant tank.MIC4428 chip U is that MOSFET drives output, and output resistance has only 6～10 Ω, and maximum output current can reach 1.5A, and maximum operation frequency can arrive 25MHz, inner integrated forward and reverse 2 out gates.It is understandable that; Said MIC4428 chip also can be substituted by a voltage follower and an active phase inverter parallel connection; The shared input end of voltage follower and active phase inverter; The output terminal of voltage follower and the output terminal of active phase inverter constitute two forward and reverse output terminals of driving circuit, and therefore, just the simple deformation on circuit structure must belong to the protection domain of the utility model.
Resistance R 1 and capacitor C 1 among the utility model embodiment; And resistance R 2 constitutes the two-way shaping circuit with capacitor C 2; Form by resistance and capacitances in series; Connect the shaping circuit that constitutes by resistance R 1 and capacitor C 1 at the output pin of MIC4428 chip 7, connect the shaping circuit that constitutes by resistance R 2 and capacitor C 2 at the output pin 5 of MIC4428 chip, and the two-way shaping circuit is connected respectively to the two ends of the LC shunt-resonant circuit that is made up of sensor coil L1; Magnetic test coil L1 and oscillating capacitance C3 form resonant tank among the figure, and an end of shaping circuit is connected the tie point place of magnetic test coil L1 and oscillating capacitance C3.
Signal at the input end independent-excited of difference exciting circuit; The input of this signal can be derived from the inside of pick-up unit or use the fixed signal source apparatus; If but adopt fixing signal source device can make cost raise; Therefore the input signal for driving circuit is directly provided by pick-up unit itself in practical application, generally adopts the TTL square-wave signal, has stable level state.The input end pin 3 of MIC4428 chip U and the pin 4 shared input end that connects together; Be input to the pin 3 of MIC4428 chip U when high level after, pass through inner phase inverter in chip pin 7 output low levels, simultaneously at chip internal; After high level is input to the pin 4 of MIC4428 chip U; At chip internal through inner voltage follower at chip pin 5 output high level, after the one-channel signal of chip U input end is through chip U, just formed differential signal opposite on the phase place this moment, differential signal further passes through resistance R 1 and resistance R 2 respectively; Because the signal of input end has certain frequency; Therefore the differential signal of square wave form can be through passing through capacitor C 1, capacitor C 2 respectively, and under the vibration environment of magnetic test coil L1 and oscillating capacitance C3, be shaped to sine wave signal, so; It is understandable that, just formed the difference pumping signal of sinusoidal wave form this moment at the positive and negative two ends of magnetic test coil L1.
The utility model embodiment adopts independent-excited difference exciting circuit; And two output terminals at the MIC4428 chip produce forward and reverse waveform signal; Form differential signal; And then, making that so just the detection signal on the magnetic test coil can be stablized, the distortionless transmission in the two ends of LC antiresonant circuit generation difference pumping signal, the ability of opposing external environmental interference is increased dramatically.
Specifically as shown in Figure 3; The positive and negative terminal of magnetic test coil L1 is connected to the input end IN+ and the input end IN-of synchronous demodulation circuit; Input end IN+ and input end IN-are connected to first gating switch and second gating switch through resistance R 3 and resistance R 4 respectively; First gating switch and second gating switch all adopt the 74HC4316 chip in the utility model embodiment; The 74HC4316 chip is to be integrated with a plurality of switches on each chip of high-speed cmos on-off circuit and to have control end, closure and shutoff that control end can CS.
The synchronous demodulation circuit of the utility model embodiment has rectified signal input end SYN; The frequency of rectified signal is the twice of the exciting signal frequency of sensor coil place resonant tank, and promptly rectified signal is 2 frequency-doubled signals of detection signal, owing to require rectified signal identical with the phase place of detection signal in the synchronous detection process; And detection signal can produce time-delay in the sensor resonant tank; Therefore, rectified signal input end SYN is connected to waveform shaping circuit through delay circuit, and delay circuit is composed in parallel by resistance R 5 and capacitor C 4; The other end ground connection of capacitor C 4; Draw the output terminal of delay circuit at the sys node place of resistance R 5 and capacitor C 4, corresponding variation can take place through phase place behind the delay circuit in rectified signal, realizes and the synchronous requirement of detection signal.Rectified signal through delay process transfers to waveform shaping circuit; Further rectified signal is handled that to form dutycycle be 50% square-wave signal; Waveform shaping circuit among the utility model embodiment is made up of d type flip flop U2; Wherein link to each other with lead between the data input pin pin two of d type flip flop U2 and the output end of oppisite phase pin 6; This output end of oppisite phase as waveform shaping circuit output terminal because the data input pin pin two of d type flip flop U2 directly connects together with output end of oppisite phase pin 6, when that rising edge occurs whenever clock trigger end pin 3; The output end of oppisite phase pin 6 of d type flip flop just triggers upset, and then to obtain dutycycle be 50% square-wave signal.Square-wave signal exports the control end of first gating switch to through the first phase inverter U3; It is the control end of 74HC4316 chip U1A among the utility model embodiment; Because the output of the first phase inverter U3 is connected to the input end of the second phase inverter U4 simultaneously, therefore the second phase inverter U4 exports voltage signal to the second gating switch opposite with the first phase inverter U3, the i.e. control end of 74HC4316 chip U1B among the utility model embodiment; So when first gating switch is connected; Second gating switch ends, i.e. two gating switch alternations are carried out the crest sampling to detection signal, and the output terminal of the output terminal of first gating switch and second gating switch is connected in parallel and forms the restituted signal output terminal; The output terminal of first gating switch and second gating switch is connected in parallel through resistance R 8 and resistance R 9 respectively in the utility model embodiment; Form the Voltage Peak peak value of restituted signal output terminal output through the detection signal of preliminary demodulation, for the noise of filtering restituted signal, the restituted signal output terminal also connects the filtering circuit that is composed in parallel by resistance R 6 and capacitor C 6; Said filtering circuit is made up of filter capacitor C6; Filter capacitor C6 other end ground connection also is connected with a current-limiting resistance R6 between filter capacitor C6 and restituted signal output terminal, in order to remedy the power attenuation of restituted signal in transmission course; The restituted signal output terminal also connects the voltage follower that is made up of operational amplifier; Among the utility model embodiment, voltage follower is connected after the filter capacitor, can remedy the decay of restituted signal in transmission course.
Synchronous demodulation circuit among the utility model embodiment is through control that rectified signal is delayed time; Be shaped to square-wave signal control gating switch then, the signal at the positive and negative two ends of magnetic test coil is carried out synchronous demodulation, concentrate output then; Therefore solved there is delay time error in rectified signal in circuit problem; Entire circuit is simple in structure, application is strong, has saved the cost of circuit, the convenient application.
More than a kind of gap sensor that the utility model embodiment is provided carried out detailed introduction; Used concrete example among this paper the principle and the embodiment of the utility model are set forth, the explanation of above embodiment just is used to help to understand the core concept of the utility model; Simultaneously, for one of ordinary skill in the art, according to the thought of the utility model, the part that on embodiment and range of application, all can change, in sum, this description should not be construed as the restriction to the utility model.
Claims (9)
1. a gap sensor is characterized in that: comprise the resonant tank that is composed in parallel by magnetic test coil and electric capacity; Be connected in the difference exciting circuit at resonant tank two ends; Be connected in the synchronous demodulation circuit at the positive and negative two ends of magnetic test coil; Be connected in the A/D change-over circuit of synchronous demodulation circuit; And governor circuit with RS485 interface; Said governor circuit connects and control A/D change-over circuit.
2. a kind of gap sensor as claimed in claim 1 is characterized in that: said governor circuit adopts fpga chip.
3. according to claim 1 or claim 2 a kind of gap sensor; It is characterized in that: said difference exciting circuit comprises MIC4428 chip, capacitor C 1, capacitor C 2, resistance R 1 and resistance R 2; Two output terminals of MIC4428 chip connect resistance R 1, resistance R 2 respectively; Resistance R 1 is connected with capacitor C 1, and resistance R 2 is connected with capacitor C 2, and capacitor C 1 and capacitor C 2 are connected respectively to the two ends of resonant tank.
4. a kind of gap sensor as claimed in claim 1 is characterized in that: said synchronous demodulation circuit comprises first gating switch and second gating switch and the rectified signal input end, the delay circuit that link to each other successively, the waveform shaping circuit that is used to generate 50% dutycycle, first phase inverter and second phase inverter that receives respectively from magnetic test coil positive and negative terminal detection signal; Wherein, The output terminal of first phase inverter also is connected to the control end of first gating switch; The output terminal of second phase inverter is connected to the control end of second gating switch, and the output terminal of the output terminal of first gating switch and second gating switch is connected in parallel and forms the restituted signal output terminal.
5. a kind of gap sensor as claimed in claim 4 is characterized in that: said first gating switch and second gating switch all adopt the 74HC4316 chip.
6. a kind of gap sensor as claimed in claim 4 is characterized in that: said delay circuit is formed by resistance and capacitances in series and through the d type flip flop shaping, draws the output terminal of time delayed signal at the series connection node place of resistance and electric capacity.
7. a kind of gap sensor as claimed in claim 4; It is characterized in that: said waveform shaping circuit is made up of gating switch; Wherein the gating control end of gating switch is by by delay circuit and inverter controlling, and the gating switch input end is connected with carrier signal, and output terminal is connected with filtering circuit.
8. a kind of gap sensor as claimed in claim 4 is characterized in that: the restituted signal output terminal also connects the filtering circuit that is composed in parallel by resistance R 6 and capacitor C 6.
9. like any described a kind of gap sensor in the claim 4 to 8, it is characterized in that: the restituted signal output terminal also connects the voltage follower that is made up of operational amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011204722530U CN202393342U (en) | 2011-11-23 | 2011-11-23 | Gap sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011204722530U CN202393342U (en) | 2011-11-23 | 2011-11-23 | Gap sensor |
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| CN202393342U true CN202393342U (en) | 2012-08-22 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2011204722530U Expired - Lifetime CN202393342U (en) | 2011-11-23 | 2011-11-23 | Gap sensor |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106643826A (en) * | 2016-11-02 | 2017-05-10 | 中国科学院电子学研究所 | Detection circuit and method of LC resonant transducer |
| CN107084660A (en) * | 2017-04-26 | 2017-08-22 | 广州精信仪表电器有限公司 | A kind of high reliability magnetic floating train suspending sensor based on redundancy structure |
| CN112747776A (en) * | 2020-12-21 | 2021-05-04 | 苏州长风航空电子有限公司 | Standard gap simulation test method and circuit for gap sensor |
-
2011
- 2011-11-23 CN CN2011204722530U patent/CN202393342U/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106643826A (en) * | 2016-11-02 | 2017-05-10 | 中国科学院电子学研究所 | Detection circuit and method of LC resonant transducer |
| CN107084660A (en) * | 2017-04-26 | 2017-08-22 | 广州精信仪表电器有限公司 | A kind of high reliability magnetic floating train suspending sensor based on redundancy structure |
| CN107084660B (en) * | 2017-04-26 | 2019-04-02 | 广州精信仪表电器有限公司 | A kind of high reliability magnetic floating train suspending sensor based on redundancy structure |
| CN112747776A (en) * | 2020-12-21 | 2021-05-04 | 苏州长风航空电子有限公司 | Standard gap simulation test method and circuit for gap sensor |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP02 | Change in the address of a patent holder |
Address after: 510630 east block, floor 3, building B, A3 self-made Industrial Park, yard 6, Yinglong Avenue, Tianhe Longdong, Guangzhou City, Guangdong Province Patentee after: GUANGZHOU JINGXIN INSTRUMENT ELECTRICAL APPLIANCE Co.,Ltd. Address before: 510630, Guangdong, Tianhe District, Guangzhou Longdong dragon road, No. 6 compound, A3 self Industrial Zone, workshop B, building on the third floor, East seat Patentee before: GUANGZHOU JINGXIN INSTRUMENT ELECTRICAL APPLIANCE Co.,Ltd. |
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| CP02 | Change in the address of a patent holder | ||
| CX01 | Expiry of patent term |
Granted publication date: 20120822 |
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| CX01 | Expiry of patent term |