CN216977929U - Split type displacement sensor - Google Patents
Split type displacement sensor Download PDFInfo
- Publication number
- CN216977929U CN216977929U CN202220068548.XU CN202220068548U CN216977929U CN 216977929 U CN216977929 U CN 216977929U CN 202220068548 U CN202220068548 U CN 202220068548U CN 216977929 U CN216977929 U CN 216977929U
- Authority
- CN
- China
- Prior art keywords
- input end
- electrically connected
- operational amplifier
- current pump
- output end
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000006073 displacement reaction Methods 0.000 title claims abstract description 23
- 238000006243 chemical reaction Methods 0.000 claims abstract description 20
- 239000000523 sample Substances 0.000 claims description 20
- 230000005284 excitation Effects 0.000 claims description 19
- 238000011896 sensitive detection Methods 0.000 claims description 13
- 230000010355 oscillation Effects 0.000 abstract description 4
- 230000002401 inhibitory effect Effects 0.000 abstract 1
- 238000004804 winding Methods 0.000 description 14
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000005669 field effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Images
Landscapes
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Abstract
The utility model provides a split type displacement sensor, which adopts a current pump to realize the conversion between voltage and current, one input end of the current pump is grounded, and a negative feedback loop and a positive feedback loop are introduced into the current pump, thereby inhibiting the oscillation phenomenon caused by the mismatching of a resistance bridge in the current pump to a certain extent; the first voltage follower isolates the negative feedback loop from the output impedance of the current pump, and the second voltage follower isolates the positive feedback loop from the output impedance of the current pump; the 0-5V voltage signal output by the filter circuit is modulated into a bias voltage signal by arranging the reverse phase adder, namely, the input voltage is raised, so that the error caused by unbalance of the resistance bridge is supplemented, and the linearity of the current output by the current pump is improved.
Description
Technical Field
The utility model relates to the field of displacement sensing, in particular to a split type displacement sensor.
Background
The differential transformer type displacement transducer (LVDT) mainly comprises a primary winding coil, two secondary winding coils with the same parameters and a movable iron core, wherein the two secondary winding coils are connected in an inverted series connection mode, and the potential difference generated by the two secondary winding coils is equal to the output voltage of the transducer. After an excitation power supply is connected to the primary winding coils, the two secondary winding coils generate induced electromotive force, when the iron core moves, the mutual inductance generated in the two secondary winding coils changes, specifically, the induced potential in one secondary winding coil is reduced, the induced potential in the other secondary winding coil is increased, the output voltage value and the displacement of the iron core have a linear relation, and the voltage value is converted into a direct current signal through a measuring circuit to be output, so that the size and the direction of displacement are known.
The existing V/I conversion circuit generally adopts a circuit formed by an operational amplifier, but the operational amplifier is influenced by zero drift and resistance element precision and cannot output no bias current, so that the problems of poor linearity of the output current of the V/I conversion circuit and low sensitivity of a displacement sensor are caused. Therefore, in order to solve the above problems, the present invention provides a split type displacement sensor, which designs a V/I conversion circuit without bias current output, and improves the linearity of the output current of the V/I conversion circuit.
SUMMERY OF THE UTILITY MODEL
In view of this, the present invention provides a split type displacement sensor, which designs a V/I conversion circuit without bias current output, and improves the linearity of the output current of the V/I conversion circuit.
The technical scheme of the utility model is realized as follows: the utility model provides a split type displacement sensor which comprises a sensor probe, a demodulation circuit, a V/I conversion circuit and a single chip microcomputer, wherein the V/I conversion circuit comprises an inverse adder, a current pump, a first voltage follower and a second voltage follower;
the output end of the sensor probe is electrically connected with the inverting input end of the inverting adder through the demodulation circuit, the output end of the inverting adder is electrically connected with the inverting input end of the current pump, the output end of the current pump is electrically connected with the inverting input end of the current pump through the first voltage follower, the output end of the current pump is electrically connected with the non-inverting input end of the current pump through the second voltage follower, and the output end of the current pump is electrically connected with the analog input end of the single chip microcomputer.
On the basis of the above technical solution, preferably, the demodulation circuit includes a phase-sensitive detection circuit and a filter circuit;
the output end of the sensor probe is electrically connected with the inverting input end of the inverting adder through a phase-sensitive detection circuit and a filter circuit which are sequentially connected in series.
On the basis of the above technical solution, preferably, the filter circuit is a second-order voltage-controlled voltage source low-pass filter.
On the basis of the technical scheme, the cutoff frequency of the second-order voltage-controlled voltage source low-pass filter is preferably 4.5 KHz.
On the basis of the technical scheme, the device preferably further comprises an excitation source;
the output end of the excitation source is electrically connected with the input end of the sensor probe.
On the basis of the above technical solution, preferably, the current pump includes resistors R25-R28 and a first operational amplifier;
the output end of the inverting adder is electrically connected with the inverting input end of the first operational amplifier through a resistor R25, the non-inverting input end of the first operational amplifier is grounded through a resistor R27, and the output end of the first operational amplifier is electrically connected with the inverting input end of the first operational amplifier through a first voltage follower and a resistor R26 which are sequentially connected in series; the output end of the first operational amplifier is electrically connected with the non-inverting input end of the first operational amplifier through a second voltage follower and a resistor R28 which are sequentially connected in series, and the output end of the first operational amplifier is electrically connected with the analog input end of the single chip microcomputer.
On the basis of the above technical solution, preferably, the inverting adder includes resistors R22-R24, a resistor R30 and a second operational amplifier;
the output end of the sensor probe is electrically connected with one end of a resistor R22 through a demodulation circuit, the other end of the resistor R22 is electrically connected with the inverting input end of a second operational amplifier, a power supply is electrically connected with the inverting input end of the second operational amplifier through a resistor R23, a resistor R24 is connected in parallel between the inverting input end and the output end of the second operational amplifier, the non-inverting input end of the second operational amplifier is grounded through a resistor R30, and the output end of the second operational amplifier is electrically connected with the inverting input end of a current pump.
Compared with the prior art, the split type displacement sensor has the following beneficial effects:
(1) the conversion between voltage and current is realized by adopting a current pump, one input end of the current pump is grounded, and a negative feedback loop and a positive feedback loop are introduced into the current pump, so that the oscillation phenomenon caused by mismatching of a resistance bridge in the current pump is inhibited to a certain extent;
(2) the first voltage follower isolates the negative feedback loop from the output impedance of the current pump, and the second voltage follower isolates the positive feedback loop from the output impedance of the current pump;
(3) the 0-5V voltage signal output by the filter circuit is modulated into a bias voltage signal by arranging the reverse phase adder, namely, the input voltage is raised, so that the error caused by unbalance of the resistance bridge is supplemented, and the linearity of the current output by the current pump is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a block diagram of a split displacement sensor according to the present invention;
FIG. 2 is a circuit diagram of a V/I conversion circuit of a split type displacement sensor according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
As shown in fig. 1, the split displacement sensor of the present invention includes an excitation source, a sensor probe, a demodulation circuit, a V/I conversion circuit, and a single chip.
And the excitation source is used for generating a sine wave excitation signal. In this embodiment, the output end of the excitation source is electrically connected to the input end of the sensor probe. The frequency of the applied stimulus signal is also one of the factors that affect the output characteristics of the differential transformer sensor. The sensor has low requirements on the waveform of an excitation power supply, and can be square wave, triangular wave, sine wave and the like, but the square wave or the triangular wave is used as an excitation signal of a primary coil of the sensor probe, and a secondary coil of the sensor probe can induce higher harmonics of different orders, which brings certain difficulty to a subsequent processing circuit. When the sine wave is used as an excitation signal of the primary coil of the sensor probe, the excitation source only contains a fundamental component, and the secondary coil of the sensor probe also only induces the fundamental component, so that more convenience is brought to a demodulation circuit. In this embodiment, the excitation source can be implemented by using the prior art, for example, a sine wave signal generator can generate a sine wave excitation signal.
The current measurement circuit of the sensor has three main implementation modes: the sensor adopts an integrated sensor special chip AD598, a differential rectification circuit and a phase sensitive detection circuit. The measuring circuit using the AD598 has better stability and reliability, but the frequency of an output excitation signal of the AD598 can only change between 20Hz and 20KHz, the cut-off frequency of a signal processing circuit using the AD598 as a sensor is 800Hz, and the actually available frequency is only within 600Hz or 700Hz, which does not meet the application requirement of a higher frequency range. In the differential rectifier circuit, a large number of diodes are used, and the rectifier characteristics are not ideal due to the threshold voltage of the diodes. The phase-sensitive detection mode is adopted, although the polarity of the output voltage is determined by using the primary excitation voltage as a phase reference, the circuit structure is simple, and the frequency-selective and phase-sensitive detection circuit has the characteristics of frequency selection and phase detection. Therefore, in this embodiment, a phase-sensitive detection method is used to measure the output signal of the sensor probe. Specifically, as shown in fig. 1, the demodulation circuit includes a phase-sensitive detection circuit and a filter circuit; the output end of the sensor probe is electrically connected with the inverting input end of the inverting adder through a phase-sensitive detection circuit and a filter circuit which are sequentially connected in series. The phase-sensitive detection circuit can be implemented by using the prior art, and will not be described in detail herein. The filter circuit is used for filtering high-frequency components of the zero-point residual voltage and high-frequency components generated by other factors; the filter circuit can be a second-order voltage-controlled voltage source low-pass filter. Since the frequency response bandwidth requires 4KHz, the cut-off frequency of the second-order voltage-controlled voltage source low-pass filter in this embodiment is 4.5 KHz.
And the V/I conversion circuit converts the voltage signal output by the demodulation circuit into a 4-20mA current signal so as to realize remote transmission. The existing V/I conversion circuit can be formed by bipolar transistors or field effect transistors, and the circuit is seriously influenced by the parameter dispersion of devices; there are also V/I conversion circuits based on operational amplifiers, which implement deep negative feedback by means of high open-loop gain index of the operational amplifier, so as to obtain excellent dc precision and output impedance, but cannot output no bias current. Therefore, in order to solve the above problem, the V/I conversion circuit of the present embodiment is provided with an inverting adder, a first voltage follower, and a second voltage follower on the basis of a current pump, and amplifies a bias current by the inverting adder to output a non-bias current; the first voltage follower and the second voltage follower are used for realizing isolation of a feedback loop and output impedance, and linearity of an output signal is improved. Specifically, as shown in fig. 1, the V/I conversion circuit includes an inverting adder, a current pump, a first voltage follower, and a second voltage follower; the output end of the sensor probe is electrically connected with the inverting input end of the inverting adder through the demodulation circuit, the output end of the inverting adder is electrically connected with the inverting input end of the current pump, the output end of the current pump is electrically connected with the inverting input end of the current pump through the first voltage follower, the output end of the current pump is electrically connected with the non-inverting input end of the current pump through the second voltage follower, and the output end of the current pump is electrically connected with the analog input end of the single chip microcomputer.
Preferably, the current pump converts the 0-5V voltage signal into a 4-20mA current signal, and when the input voltage is 0V, the current pump outputs the 4mA current signal; when the input voltage is 5V, the current pump outputs a current signal of 20 mA. Further preferably, as shown in FIG. 2, the current pump includes resistors R25-R28 and a first operational amplifier; the output end of the inverting adder is electrically connected with the inverting input end of the first operational amplifier through a resistor R25, the non-inverting input end of the first operational amplifier is grounded through a resistor R27, and the output end of the first operational amplifier is electrically connected with the inverting input end of the first operational amplifier through a first voltage follower and a resistor R26 which are sequentially connected in series; the output end of the first operational amplifier is electrically connected with the non-inverting input end of the first operational amplifier through a second voltage follower and a resistor R28 which are sequentially connected in series, and the output end of the first operational amplifier is electrically connected with the analog input end of the single chip microcomputer. The resistors R25-R28 have the same resistance value, so that a balanced resistor bridge is formed, wherein the output end of the first operational amplifier, the resistor R26 and the inverting input end of the first operational amplifier form a negative feedback loop; the output end of the first operational amplifier, the resistor R28 and the non-inverting input end of the first operational amplifier form a positive feedback loop, and the negative feedback loop and the positive feedback loop inhibit oscillation phenomena caused by mismatching of the resistors R25-R28 to a certain extent.
Preferably, since the negative feedback loop and the positive feedback loop in the current pump may affect the linearity of the output current of the current pump, in this embodiment, a first voltage follower and a second voltage follower are respectively disposed in the negative feedback loop and the positive feedback loop, where the first voltage follower isolates the negative feedback loop from the output impedance of the current pump, and the second voltage follower isolates the positive feedback loop from the output impedance of the current pump. The first voltage follower and the second voltage follower can be implemented by using a circuit structure as shown in fig. 2, where U9.2 denotes the first voltage follower and U8.1 denotes the second voltage follower.
Preferably, in an actual circuit, the resistance values of the resistor bridges of the current pump cannot be absolutely identical, so that the resistor bridges may be unbalanced, resulting in poor linearity of the current output from the current pump. Therefore, in order to solve the above problem, the present embodiment provides an inverting adder to modulate the 0-5V voltage signal output by the filter circuit into the bias voltage signal, i.e. to raise the input voltage, so as to compensate the error caused by the unbalance of the resistor bridge. The two-end input of the inverting adder is input voltage and bias voltage output by the filter circuit respectively, wherein the bias voltage is a +12V voltage source, and after the input voltage and the bias voltage are added by the inverting adder, the output voltage of the inverting adder is the sum of the two-end input. Further preferably, as shown in fig. 2, the inverting adder includes resistors R22-R24, a resistor R30 and a second operational amplifier; the output end of the sensor probe is electrically connected with one end of a resistor R22 through a demodulation circuit, the other end of the resistor R22 is electrically connected with the inverting input end of a second operational amplifier, a power supply is electrically connected with the inverting input end of the second operational amplifier through a resistor R23, a resistor R24 is connected in parallel between the inverting input end and the output end of the second operational amplifier, the non-inverting input end of the second operational amplifier is grounded through a resistor R30, and the output end of the second operational amplifier is electrically connected with the inverting input end of a current pump. The output voltage of the inverting adder is related to the values of the voltages of the two-terminal input signals and the resistances of the resistors R22-R24, and the output voltage of the inverting adder can be changed by adjusting the resistances of the resistors R22-R24.
The working principle of the embodiment is as follows: excitation signals generated by an excitation source are output to two ends of the primary winding coil, the first secondary winding coil and the second secondary winding coil generate potential difference to move the movable iron core, and amplitude modulation signals generated by the first secondary winding coil and the second secondary winding coil are output to the phase-sensitive detection circuit; the phase-sensitive detection circuit demodulates amplitude-modulated signals, the demodulated signals are output to the filter circuit, high-frequency components are filtered by the filter circuit, then the high-frequency components are subjected to voltage lifting by the inverting adder and then input into the current pump, the current pump converts input voltage signals into 4-20mA current signals, and the 4-20mA current signals are input into the single chip microcomputer to be subjected to A/D conversion.
The beneficial effect of this embodiment does: the conversion between voltage and current is realized by adopting a current pump, one input end of the current pump is grounded, and a negative feedback loop and a positive feedback loop are introduced into the current pump, so that the oscillation phenomenon caused by mismatching of a resistance bridge in the current pump is inhibited to a certain extent;
the first voltage follower isolates the negative feedback loop from the output impedance of the current pump, and the second voltage follower isolates the positive feedback loop from the output impedance of the current pump;
the 0-5V voltage signal output by the filter circuit is modulated into a bias voltage signal by arranging the reverse phase adder, namely, the input voltage is raised, so that the error caused by unbalance of the resistance bridge is supplemented, and the linearity of the current output by the current pump is improved.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (7)
1. The utility model provides a split type displacement sensor, its includes sensor probe, demodulation circuit, V/I converting circuit and singlechip, its characterized in that: the V/I conversion circuit comprises an inverting adder, a current pump, a first voltage follower and a second voltage follower;
the output end of the sensor probe is electrically connected with the reverse phase input end of the reverse phase adder through the demodulation circuit, the output end of the reverse phase adder is electrically connected with the reverse phase input end of the current pump, the output end of the current pump is electrically connected with the reverse phase input end of the current pump through the first voltage follower, the output end of the current pump is electrically connected with the non-inverting input end of the current pump through the second voltage follower, and the output end of the current pump is electrically connected with the analog input end of the single chip microcomputer.
2. The split displacement sensor according to claim 1, wherein: the demodulation circuit comprises a phase-sensitive detection circuit and a filter circuit;
the output end of the sensor probe is electrically connected with the inverting input end of the inverting adder through a phase-sensitive detection circuit and a filter circuit which are sequentially connected in series.
3. The split displacement sensor according to claim 2, wherein: the filter circuit is a second-order voltage-controlled voltage source low-pass filter.
4. A split displacement sensor as claimed in claim 3, wherein: the cut-off frequency of the second-order voltage-controlled voltage source low-pass filter is 4.5 KHz.
5. The split displacement sensor according to claim 1, wherein: the device also comprises an excitation source;
and the output end of the excitation source is electrically connected with the input end of the sensor probe.
6. The split displacement sensor according to claim 1, wherein: the current pump comprises resistors R25-R28 and a first operational amplifier;
the output end of the inverting adder is electrically connected with the inverting input end of the first operational amplifier through a resistor R25, the non-inverting input end of the first operational amplifier is grounded through a resistor R27, and the output end of the first operational amplifier is electrically connected with the inverting input end of the first operational amplifier through a first voltage follower and a resistor R26 which are sequentially connected in series; the output end of the first operational amplifier is electrically connected with the non-inverting input end of the first operational amplifier through a second voltage follower and a resistor R28 which are sequentially connected in series, and the output end of the first operational amplifier is electrically connected with the analog input end of the single chip microcomputer.
7. The split type displacement sensor according to claim 1 or 6, wherein: the inverting adder comprises resistors R22-R24, a resistor R30 and a second operational amplifier;
the output end of the sensor probe is electrically connected with one end of a resistor R22 through a demodulation circuit, the other end of the resistor R22 is electrically connected with the inverting input end of a second operational amplifier, a power supply is electrically connected with the inverting input end of the second operational amplifier through a resistor R23, a resistor R24 is connected between the inverting input end and the output end of the second operational amplifier in parallel, the non-inverting input end of the second operational amplifier is grounded through a resistor R30, and the output end of the second operational amplifier is electrically connected with the inverting input end of a current pump.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220068548.XU CN216977929U (en) | 2022-01-11 | 2022-01-11 | Split type displacement sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220068548.XU CN216977929U (en) | 2022-01-11 | 2022-01-11 | Split type displacement sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216977929U true CN216977929U (en) | 2022-07-15 |
Family
ID=82352103
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202220068548.XU Active CN216977929U (en) | 2022-01-11 | 2022-01-11 | Split type displacement sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN216977929U (en) |
-
2022
- 2022-01-11 CN CN202220068548.XU patent/CN216977929U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110927428B (en) | Wide-range wide-band high-precision magnetic balance type current measuring device | |
| CN1580788A (en) | Direct current sensor | |
| CN109556647A (en) | A kind of low-frequency noise inhibition device and method of tunnel magneto-resistance effect sensor | |
| CN112834815A (en) | Fluxgate digital current sensor based on pulse amplitude detection method | |
| CN107449949B (en) | Device for applying DC bias voltage to AC sine wave signal source | |
| CN111623698A (en) | Eddy current displacement sensor circuit with nonlinear correction function | |
| CN110824229A (en) | Single-magnetic-core multi-winding magnetic balance type current detection device | |
| CN216977929U (en) | Split type displacement sensor | |
| CN111948438B (en) | Low-cost current sensor | |
| Vyroubal | Eddy-current displacement transducer with extended linear range and automatic tuning | |
| US7639051B2 (en) | Circuit arrangement for rectifying the output voltage of a sensor that is fed by an oscillator | |
| CN109030850B (en) | Driving device for stable modulation of magnetic field of MHD angular velocity sensor | |
| CN115327202B (en) | TMR current sensor | |
| Kumar et al. | A simple signal conditioning scheme for inductive sensors | |
| CN216977775U (en) | Pen-type pressure-changing displacement sensor | |
| CA1196382A (en) | Current sensing circuit for motor controls | |
| CN211579938U (en) | Differential capacitance alternating current bridge sensing control circuit | |
| CN114487932A (en) | High-precision parallel measurement method for asymmetric coupling factors of differential transformer | |
| CN204008813U (en) | A kind of magnetic modulation type current transformer | |
| CN114113781A (en) | Frequency measuring circuit of power system | |
| CN204142265U (en) | A kind of sensor detection circuit | |
| CN113552406A (en) | High-precision residual current detection device powered by single power supply | |
| CN215452889U (en) | High-precision digital demodulation circuit of eddy current sensor | |
| CN116794560B (en) | Broadband residual current sensor | |
| CN221227507U (en) | Low-frequency charge amplifying circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CP01 | Change in the name or title of a patent holder | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 441000 Group 8, huozhuang village, Nancheng, Zaoyang City, Xiangyang City, Hubei Province Patentee after: Hubei Mirang Technology Co.,Ltd. Address before: 441000 Group 8, huozhuang village, Nancheng, Zaoyang City, Xiangyang City, Hubei Province Patentee before: ZAOYANG MIRAN SCIENCE & TECHNOLOGY CO.,LTD. |