CN210952688U - Integrated differential transformer type displacement sensor - Google Patents

Abstract

The utility model discloses an integrated differential transformer type displacement sensor, which consists of an RC sine oscillation circuit, a zero residual voltage compensation circuit, a common mode signal suppression circuit, a phase sensitive detection circuit, a wireless gain multi-path feedback type low-pass circuit, a direct current amplification circuit and a three-digit and half-digit display head, the RC positive selection oscillating circuit is used for a carrier signal generating circuit, the RC positive selection oscillating circuit is set as a 5kHz sine wave oscillating circuit, the common-mode signal suppression circuit suppresses the common-mode signal during the signal transmission of the sensor, the phase-sensitive detection circuit sets a 5kHz sinusoidal drive signal, the direct current signal of the filter circuit of the wireless gain multi-path feedback type low-pass circuit is set as a signal after low-pass filtering, the phase sensitive detection circuit is a precise rectification type full-wave phase sensitive detection circuit and the signal is a 5kHz sine drive signal. The utility model has the advantages that: the circuit precision and the circuit stable output responsiveness are improved.

Description

Integrated differential transformer type displacement sensor

Technical Field

The utility model relates to a sensor field of making specifically indicates a differential transformer formula displacement sensor of integral type.

Background

The differential transformer type displacement sensor has the advantages of reliable work, convenient use and maintenance, long service life, high repeatability precision, good dynamic characteristic, simple structure, small volume and the like, and is particularly suitable for displacement measurement of moving parts in severe fields of high temperature, high humidity, oil stain and the like.

The existing structure is changed, the output sinusoidal signal of the differential transformer sensor for measuring the displacement is stably amplified by a fixed multiple, the signal is processed into a direct current signal corresponding to the displacement, and the direct current signal can be displayed on a three-position and half-digital display meter, so that the circuit precision and the circuit stable output responsiveness are improved.

SUMMERY OF THE UTILITY MODEL

The utility model provides a technical scheme does: an integrated differential transformer type displacement sensor, which comprises an RC sine oscillation circuit, a zero-point residual voltage compensation circuit, a common-mode signal suppression circuit, a phase-sensitive detection circuit, a wireless gain multi-path feedback type low-pass filter circuit, a direct current amplification circuit and a three-digit half-number display, wherein the RC positive selection oscillation circuit is used for a carrier signal generation circuit, the RC positive selection oscillation circuit is set as a 5kHz sine-wave oscillation circuit, the 5kHz sine-wave oscillation circuit selects R1-R2-2.37 k omega, C1-C2-0.013 muF, R3-5.1 k omega, R F-10.0 k omega and R4-2.0 k omega, the common-mode signal suppression circuit suppresses a common-mode signal during sensor signal transmission, the phase-sensitive detection circuit is set as a 5kHz sine-drive signal, the direct-current signal of the wireless gain multi-path feedback type low-pass filter circuit is set as a signal after low-pass filtering, phase-sensitive detection circuit establishes to accurate rectification type full wave phase-sensitive detection circuit and signal and establishes to 5kHz sinusoidal drive signal, accurate rectification type full wave phase-sensitive detection circuit is equipped with opposite phase's square wave signal control switching device Q1, Q2, Q1, Q2's closure and disconnection divide into two the tunnel with 5kHz sinusoidal drive signal's output signal, directly form zero crossing comparator through LM311 chip all the way, and another way is earlier through an inverting amplifier, outputs the inverted sine wave, forms zero crossing comparator through the LM311 chip again, produces the opposite square wave signal of two phases, wireless gain multichannel feedback type low pass filter circuit direct current signal filtering wave front voltage value establishes to-127.7 mV, and post-filter direct current voltage is about 255.7 mV.

The RC sinusoidal oscillation circuit 1 is connected with a resistor R1 and a capacitor C1 in series, and connected with a resistor R2 and a capacitor C2 in parallel to form an RC series-parallel frequency selection network, wherein the frequency selection network selects Ri-Rz-R, and C1-C2-C.

The direct-current signal R1 of the wireless gain multi-path feedback low-pass filter circuit 5 is 1.74K Ω, R2 is 2K Ω, R3 is 13.7K Ω, and the gain K is 1+ R3/R2 is 1+13.7/2 is 7.85.

The three-position half-number display head is designed into an AT89C51 model single chip microcomputer and a 12-position AD conversion chip model TLC 2543.

Due to the adoption of the technical scheme, the beneficial effects of the utility model reside in that: other electronic components such as operational amplifiers used in the circuit are carefully considered, so that the cost is reduced as much as possible while the performance of the circuit is ensured. The phase-sensitive detection link of the circuit uses a precise rectification type full-wave phase-sensitive detection circuit, can ensure the precision of the circuit and is superior to a switch type and addition type phase-sensitive detection circuit. The circuit can enter a stable output state only about 36ms from power-on, and has good responsiveness. Through simulation and test, in the tested circuit, the absolute value of the difference between the actual output value and the theoretical output value of the circuit is less than 0.01V, and the circuit precision is high.

Drawings

Fig. 1 is a schematic view of the processing flow structure of the integrated differential transformer type displacement sensor of the present invention.

Fig. 2 is a schematic diagram of the frequency-selecting network circuit structure of the integrated differential transformer type displacement sensor of the present invention.

Fig. 3 is a schematic diagram of the 5kHz sine driving circuit of the integrated differential transformer type displacement sensor of the present invention.

Fig. 4 is a schematic diagram of a zero-point residual voltage compensation circuit of the integrated differential transformer type displacement sensor according to the present invention.

Fig. 5 is a schematic diagram of a second structure of the zero residual voltage compensation circuit of the integrated differential transformer type displacement sensor.

Fig. 6 is a schematic diagram of an OP07 circuit structure of the integrated differential transformer type displacement sensor according to the present invention.

Fig. 7 is a schematic diagram of a dc amplifying circuit of the integrated differential transformer type displacement sensor of the present invention.

As shown in the figure: 1. an RC sine oscillation circuit; 2. a zero-point residual voltage compensation circuit 3 and a common-mode signal suppression circuit; 4. a phase sensitive detection circuit; 5. a wireless gain multi-path feedback type low-pass filter circuit; 6. a DC amplification circuit; 7. a three-digit and half-digit display head; 8. a precise rectification type full-wave phase-sensitive detection circuit.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

With reference to fig. 1, an integrated differential transformer type displacement sensor is composed of an RC sinusoidal oscillation circuit 1, a zero-point residual voltage compensation circuit 2, a common-mode signal suppression circuit 3, a phase-sensitive detection circuit 4, a wireless gain multi-path feedback type low-pass filter circuit 5, a direct-current amplification circuit 6, and a three-digit and half-digit display meter head 7;

the utility model adopts the RC sine wave oscillating circuit as the carrier signal generating circuit, the RC sine wave oscillating balance series resistor R1 and capacitor C1, and parallel resistor R2 and capacitor C2 to form the RC series-parallel frequency selecting network, as shown in fig. 2, R1 ═ R2 ═ R, C1 ═ C2 ═ C, the RC selected oscillating circuit is set as the 5kHz sine wave oscillating circuit as shown in fig. 3, the 5kHz sine wave oscillation selects R1 ═ R2 ═ 2.37k Ω, C1 ═ C2 ═ 0.013 μ F, R3 ═ 5.1k Ω, R F ═ 10.0k Ω, R4 ═ 2.0k Ω, the operation amplifier in the oscillating circuit is used for the carrier and as the reference signal of the sensitive detection, and the frequency of the circuit is 5kHz, the frequency requirement is not too high, and it is not too precise to need to be too much, the general factors such as overall circuit cost are considered, the analog amplifier 741 widely used, the operational amplifier can completely meet the design requirements of the partial circuit; the zero-point residual voltage compensation circuit 2 applies alternating voltage to the primary winding of the sensor wire frame, and due to the factors such as asymmetry of electrical parameters and geometric dimensions of two secondary coils of the sensor, nonlinearity of magnetic materials and the like, even if the iron core is positioned at the central position, the output voltage is not equal to zero, namely zero-point residual voltage, and the zero-point residual voltage must be compensated, for example, a first zero-point residual voltage compensation circuit and a second zero-point residual voltage compensation circuit which are commonly used in fig. 4 and fig. 5 are simulated, the utility model selects C3 to be 0.02 muf, and two potentiometers both adopt 10k omega;

the common mode signal suppression circuit 3 suppresses the common mode signal during the sensor signal transmission, and in order to obtain a high common mode rejection ratio, the operational amplifier in the circuit must select an integrated operational amplifier with a high common mode rejection ratio, so that an OP07 circuit is adopted as shown in FIG. 6, R7, R8 and RP common mode compensation circuits are connected to two input ends of N3, and by adjusting RP, the asymmetry of resistance can be compensated, and a higher common mode rejection ratio is obtained;

the phase-sensitive detection circuit 4 is set as a 5kHz sine drive signal, the phase-sensitive detection circuit 4 is set as a precise rectification type full-wave phase-sensitive detection circuit 8, the signal is set as a 5kHz sine drive signal, the precise rectification type full-wave phase-sensitive detection circuit 8 is provided with square wave signal control switching devices Q1 and Q2 with opposite phases, the output signal of the 5kHz sine drive signal is divided into two paths by the closing and opening of Q1 and Q2, one path directly passes through an LM311 chip to form a zero comparator, the other path passes through an inverting amplifier to output an inverted sine wave, and then passes through an LM311 chip to form a zero comparator to generate two square wave signals with opposite phases, the filtering front voltage value of the direct current signal of the wireless gain multi-path feedback type low-pass filter circuit 5 is set to-127.7 mV, the precision of the filtered direct current voltage is about 255.7mV, and the detection waveform effect of the circuit is;

the direct current signal of the filter circuit of the wireless gain multi-path feedback type low-pass filter circuit 5 is set as a signal after low-pass filtering, specifically, the direct current signal is second-order wireless gain multi-path feedback Butterworth low-pass filtering, the effective value of the voltage before filtering is-127.7 mV, the direct current voltage after filtering is about 255.7mV, and the low-pass filtering effect is good;

the output voltage of the direct current amplifying circuit 6 after low-pass filtering is about 0.255V, and the output direct current voltage should be 2V because the difference between the two secondary coils of the sensor is the largest. The gain of the dc amplification circuit should be 2/0.255 ≈ 7.84. The designed dc amplifier circuit is shown in fig. 7. The OP-amp still selects the precision OP-amp 07. R1 is 1.74K Ω, R2 is 2K Ω, R3 is 13.7K Ω, and the gain K is 1+ R3/R2 is 1+13.7/2 is 7.85;

the design of tribit half digital display gauge outfit, the complexity of considering the design and the cost that reduces as far as possible, the utility model discloses a 12 bit AD conversion chip TLC2543 of AT89C51 singlechip and TI company carries out the design of tribit half digital display. TLC2543 converts the analog quantity into digital quantity to communicate with AT89C51, and AT89C51 singlechip shows the digital quantity on the four-digit LED nixie tube. The three-digit and half-digit display head is simulated by using software. In order to simulate the voltage of-2 to 2V output by a direct current amplifying circuit, a slide rheostat is arranged in a Proteus, the analog quantity input by a TLC2543 is adjusted by changing the resistance value, the TLC2543 is a 12-bit analog-to-digital converter with 11 input ports, and the TLC2543 is high in conversion speed, good in stability and low in price.

The utility model discloses implement the step: the circuit of the utility model starts to respond about 22ms after being electrified and enters a stable state about 36ms after being electrified; therefore, the displacement sensor has good responsiveness and can quickly respond to displacement change; when the proportion of the coil is 20000:150:50, the theoretical output voltage is 2.000V, the simulation output voltage is 2.006V, the voltage precision is high, and the general use requirement can be met; when the proportion of the coil is 20000:50:150, the theoretical output voltage is-2.000V, the simulation output voltage is-2.008V, the voltage precision is also higher, and the general use requirement can be met; when the coil proportion is 20000:100:100, the theoretical output voltage is 0V, the simulation output voltage is 525.78 μ V, and almost approaches to 0; when the iron core is in the middle position, the output voltage is almost zero, and the circuit precision is high.

Other electronic components such as operational amplifiers used in the circuit are carefully considered, so that the cost is reduced as much as possible while the performance of the circuit is ensured. The phase-sensitive detection link of the circuit uses a precise rectification type full-wave phase-sensitive detection circuit, can ensure the precision of the circuit and is superior to a switch type and addition type phase-sensitive detection circuit. The circuit can enter a stable output state only about 36ms from power-on, and has good responsiveness. In the circuit tested by the simulation and test case, the absolute value of the difference between the actual output value and the theoretical output value of the circuit is less than 0.01V, and the circuit precision is high.

The present invention and the embodiments thereof have been described above, but the description is not limited thereto, and the embodiment shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. In summary, those skilled in the art should understand that they should not be limited to the embodiments described above, and that they can design the similar structure and embodiments without departing from the spirit of the invention.

Claims (4)

1. The utility model provides an integral type differential transformer formula displacement sensor which characterized in that: the integrated differential transformer type displacement sensor is composed of an RC sinusoidal oscillation circuit (1), a zero-point residual voltage compensation circuit (2), a common-mode signal suppression circuit (3), a phase-sensitive detection circuit (4), a wireless gain multi-path feedback type low-pass filter circuit (5), a direct current amplification circuit (6) and a three-position half-number display meter head (7), wherein the RC selected oscillation circuit (1) is used for generating a carrier signal, the RC selected oscillation circuit (1) is set to be a 5kHz sinusoidal oscillation circuit, the 5kHz sinusoidal oscillation selects R1-R2-2.37 k omega, C1-C2-0.013 mu F, R3-5.1 k omega, Rf-10.0 k omega and R4-2.0 k omega, the common-mode signal suppression circuit (3) suppresses common-mode signals when sensor signals are transmitted, the phase-sensitive detection circuit (4) is set to be a 5kHz sinusoidal driving signal, the direct current signal of the filter circuit of the wireless gain multi-path feedback type low-pass filter circuit (5) is set as a signal after low-pass filtering, the phase-sensitive detection circuit (4) is a precise rectification type full-wave phase-sensitive detection circuit (8) and the signal is set as a 5kHz sine drive signal, the precise rectification type full-wave phase-sensitive detection circuit (8) is provided with square wave signal control switching devices Q1 and Q2 with opposite phases, the Q1 and the Q2 are closed and opened to divide the output signal of the 5kHz sine driving signal into two paths, one path of the output signal directly passes through the LM311 chip to form a zero-crossing comparator, the other path of the output signal passes through an inverting amplifier to output an inverted sine wave, then passes through the LM311 chip to form the zero-crossing comparator, two square wave signals with opposite phases are generated, the voltage value before the direct current signal filtering of the wireless gain multi-path feedback type low-pass filtering circuit (5) is set to be-127.7 mV, and the direct current voltage after filtering is about 255.7 mV.

2. The integrated differential transformer displacement sensor of claim 1, wherein: the RC sinusoidal oscillation circuit (1) is connected with a resistor R1 and a capacitor C1 in series, and connected with a resistor R2 and a capacitor C2 in parallel to form an RC series-parallel frequency selection network, wherein the frequency selection network selects Ri-Rz-R, and C1-C2-C.

3. The integrated differential transformer displacement sensor of claim 1, wherein: the direct-current signal R1 of the wireless gain multipath feedback type low-pass filter circuit (5) is 1.74K omega, R2 is 2K omega, R3 is 13.7K omega, and the gain is that K is 1+ R3/R2 is 1+13.7/2 is 7.85.

4. The integrated differential transformer displacement sensor of claim 1, wherein: the three-position half-number display head is designed into an AT89C51 model single chip microcomputer and a 12-position AD conversion chip model TLC 2543.

Images