CN218068140U

CN218068140U - Frequency sweep detection circuit and intelligent acquisition instrument thereof

Info

Publication number: CN218068140U
Application number: CN202222020330.XU
Authority: CN
Inventors: 肖毅; 敖发祥; 刘顺; 熊渐; 陶亮; 朱培淑
Original assignee: Wuhan Huahe Iot Technology Co ltd
Current assignee: Wuhan Huahe Iot Technology Co ltd
Priority date: 2022-08-02
Filing date: 2022-08-02
Publication date: 2022-12-16
Anticipated expiration: 2032-08-02

Abstract

The utility model provides a sweep frequency detection circuit and an intelligent acquisition instrument thereof, belonging to the technical field of sensor signal acquisition equipment and comprising a vibrating wire sensor, an excitation power supply unit, a sweep frequency response receiving unit, a signal conditioning unit and an MCU; the excitation power supply unit is used for generating excitation voltage and inputting the excitation voltage into the vibrating wire sensor; the output end of the MCU is electrically connected with the excitation power supply unit, and the MCU selectively adjusts the excitation voltage and frequency; the sweep frequency response receiving unit is used for receiving a return signal generated by the vibrating wire sensor; the input end of the sweep frequency response receiving unit is electrically connected with the output end of the vibrating wire sensor, and the output end of the sweep frequency response receiving unit is electrically connected with the input end of the signal conditioning unit; the signal conditioning unit compares and limits the alternating current component of the return signal to obtain a square wave signal, and the signal conditioning unit sends the square wave signal into the MCU.

Description

Frequency sweep detection circuit and intelligent acquisition instrument thereof

Technical Field

The utility model relates to a sensor signal acquisition equipment technical field especially relates to a frequency sweep detection circuitry and intelligent acquisition appearance thereof.

Background

The acquisition base station has a plurality of different types of physical quantities to be monitored, and a plurality of different types of sensors are often equipped on the site to monitor the plurality of physical quantities respectively. The output interface types of the sensors are not consistent, such as a digital signal output interface, an analog signal output interface, or a frequency signal output interface of a vibrating wire sensor. In order to deal with the output types of different sensors, a signal acquisition instrument arranged on the site of an acquisition base station needs to be provided with a plurality of different input interfaces and corresponding signal processing modules to respectively and independently process different types of input signals. When the frequency sweeping detection of the sensor is needed on site, a special frequency sweeping instrument is often needed to be configured, which greatly increases the overall cost and volume of the device, although a portable digital frequency sweeping instrument is disclosed in chinese patent No. CN216870660U, the circuit provided by the portable digital frequency sweeping instrument is still relatively complex, the devices are numerous, and the design process is difficult.

In view of this, it is very necessary to develop a sensor sweep frequency driving circuit with compact structure and reliable performance, and a corresponding intelligent acquisition instrument, which is portable and suitable for acquiring and detecting signals of a base station.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model provides a compact structure's sweep frequency detection circuitry and high intelligent acquisition appearance of integrated level.

The technical scheme of the utility model is realized like this: on one hand, the utility model provides a sweep frequency detection circuit, which comprises a vibrating wire sensor, an excitation power supply unit (1), a sweep frequency response receiving unit (2), a signal conditioning unit (3) and an MCU;

the excitation power supply unit (1) is used for generating an excitation voltage and inputting the excitation voltage into the vibrating wire sensor; the output end of the MCU is electrically connected with the excitation power supply unit (1), and the MCU selectively adjusts the excitation voltage and frequency;

the sweep frequency response receiving unit (2) is used for receiving a return signal generated by the vibrating wire sensor; the input end of the sweep frequency response receiving unit (2) is electrically connected with the output end of the vibrating wire sensor, and the output end of the sweep frequency response receiving unit (2) is electrically connected with the input end of the signal conditioning unit (3); the sweep frequency response receiving unit (2) carries out direct current component isolation on the return signal;

the signal conditioning unit (3) compares and limits the alternating current component of the return signal to obtain a square wave signal, and the signal conditioning unit (3) sends the square wave signal into the MCU.

On the basis of the technical scheme, preferably, the excitation power supply unit (1) comprises a constant current driving chip U13, an MOS (metal oxide semiconductor) tube Q8, a triode Q7 and a triode Q8; the input end and the enabling end of the constant current driving chip U13 are electrically connected with a power supply VPOWER respectively; the output end of the constant current driving chip U13 is electrically connected to the anode of the diode D2, and the cathode of the diode D2 is electrically connected to one end of the resistor R18, one end of the capacitor C10, one end of the capacitor C11, one end of the resistor R32, and the source of the MOS transistor Q8, respectively; the other end of the resistor R18 is electrically connected with the feedback input end of the constant current driving chip U13, one end of the resistor R19 and one end of the resistor R23 respectively, and the other end of the resistor R19, the other end of the capacitor C10 and the other end of the capacitor C11 are grounded; the other end of the resistor R23 is electrically connected with a collector of the triode Q7, an emitter of the triode Q7 is grounded, and a base of the triode Q7 is electrically connected with an output end HV CTL of the MCU; the other end of the resistor R32 and the grid electrode of the MOS tube Q8 are electrically connected with the collector electrode of the triode Q9, and the drain electrode of the MOS tube Q8 is electrically connected with the input end of the vibrating wire sensor; the emitting electrode of the triode Q9 is grounded, and the base electrode of the triode Q9 is electrically connected with the output end K JL of the MCU; the MCU selectively conducts the triode Q7 or the triode Q8, and changes the size or the frequency of the output voltage V JL of the constant current driving chip U13.

Preferably, the swept frequency response receiving unit (2) comprises a first operational amplifier U5 and a voltage regulator diode DZ2; the output end of the vibrating wire sensor is electrically connected with one end of a resistor R35, the other end of the resistor R35 is electrically connected with the cathode of the voltage stabilizing diode DZ2, one end of a resistor R36, one end of a resistor R37 and one end of a capacitor C12 respectively, and the anode of the voltage stabilizing diode DZ2 is grounded; the other end of the capacitor C12 is electrically connected with one end of the resistor R38 and the inverting input end of the first operational amplifier U5; the other end of the resistor R36 is grounded, the other end of the resistor R37 is electrically connected with one end of the capacitor C13, and the other end of the capacitor C13 is electrically connected with the other end of the resistor R38 and the output end of the first operational amplifier U5; the non-inverting input end of the first operational amplifier U5 is electrically connected with one end of the capacitor C15, and the other end of the capacitor C15 is grounded; the output end of the first operational amplifier U5 is also electrically connected with one end of a capacitor C16, and the other end of the capacitor C16 is electrically connected with the input end of the signal conditioning unit (3).

Preferably, the signal conditioning unit (3) comprises a second operational amplifier U6, a third operational amplifier U7, diodes D3 and D5; the output end of the sweep frequency response receiving unit (2) and one end of a resistor R39 are electrically connected with the non-inverting input end of a second operational amplifier U6 respectively, and the other end of the resistor R39 is electrically connected with a reference voltage VERF; one end of the resistor R40 is electrically connected with the inverting input end of the second operational amplifier U6 and one end of the resistor R41, the other end of the resistor R40 is electrically connected with one end of the capacitor C22, and the other end of the capacitor C22 is grounded; the other end of the resistor R41 is electrically connected with the output end of the second operational amplifier U6; the output end of the second operational amplifier U6 is also electrically connected to one end of the capacitor C23, the other end of the capacitor C23 is electrically connected to one end of the resistor R42, the other end of the resistor R42 is electrically connected to the inverting input end of the third operational amplifier U7 and one end of the resistor R43, respectively, and the other end of the resistor R43 is electrically connected to the output end of the third operational amplifier U7; the reference voltage VERF is also electrically connected with the non-inverting input end of the third operational amplifier U7; the output end of the third operational amplifier U7 is electrically connected with the input end of the MCU.

On the other hand, the utility model also provides an intelligent acquisition instrument, which comprises a voltage signal acquisition unit (4), a current signal acquisition unit (5), a resistance signal acquisition unit (6), a channel selector (7), an analog-to-digital conversion unit (8) and the sweep frequency detection circuit; the output end of the voltage signal acquisition unit (4), the output end of the current signal acquisition unit (5) or the output end of the resistance signal acquisition unit (6) are respectively and correspondingly electrically connected with different input channels of the channel selector (7); the output end of the channel selector (7) is electrically connected with the input end of the analog-to-digital conversion unit (8), and the output end of the analog-to-digital conversion unit (8) is in communication connection with the MCU; the voltage signal acquisition unit (4) is selectively and electrically connected with the sensor for outputting voltage signals; the current signal acquisition unit (5) is selectively and electrically connected with a sensor for outputting a current signal, and the resistance signal acquisition unit (6) is selectively and electrically connected with a sensor for outputting a resistance value change signal; the output end of the MCU is electrically connected with the channel selector (7), and the channel selector (7) selects one of the voltage signal acquisition unit (4), the current signal acquisition unit (5) or the resistance signal acquisition unit (6) to be electrically connected with the analog-to-digital conversion unit (8).

Preferably, the voltage signal acquisition unit (4) comprises a fourth operational amplifier U10 and a plurality of divider resistors; a sensor for outputting a voltage signal is electrically connected with one end of the resistor R47 and one end of the capacitor C28 respectively, the other end of the resistor R47 is electrically connected with one end of the resistor R48 and the non-inverting input end of the fourth operational amplifier U10 respectively, and the other end of the resistor R48 and the other end of the capacitor C28 are grounded; the inverting input end and the output end of the fourth operational amplifier U10 are electrically connected; the output end of the fourth operational amplifier U10 is electrically connected to one end of a voltage dividing resistor R49, the other end of the voltage dividing resistor R49 is electrically connected to one end of a voltage dividing resistor R50, one end of a capacitor C29 and the input channel 0 of the channel selector (7), and the other end of the capacitor C29 is grounded; the other end of the voltage dividing resistor R50 is electrically connected with one end of the voltage dividing resistor R51, one end of the capacitor C30 and the input channel 6 of the channel selector (7), and the other end of the voltage dividing resistor R51 and the other end of the capacitor C30 are grounded.

Preferably, the resistance signal acquisition unit (6) comprises a fifth operational amplifier U11 and a sixth operational amplifier U12; the reference voltage signal is electrically connected with the non-inverting input end of the fifth operational amplifier U11, the inverting input end of the fifth operational amplifier U11 is electrically connected with the output end thereof, the output end of the fifth operational amplifier U11 is electrically connected with one end of the resistor R53, the other end of the resistor R53 is electrically connected with the sensor for outputting the resistance value change signal and the non-inverting input end of the sixth operational amplifier U12 respectively, the inverting input end of the sixth operational amplifier U12 is electrically connected with the output end thereof, and the output end of the sixth operational amplifier U12 is electrically connected with the input channel 2 of the channel selector (7).

Preferably, the communication device further comprises a communication unit (9), wherein the communication unit (9) comprises a 4G communication module U1, a SIM card and an antenna, and the pin 9, the pin 10, the pin 11 and the pin 12 of the 4G communication module U1 are electrically connected with the contacts of the SIM card in a one-to-one correspondence manner; a pin 36 and a pin 37 of the 4G communication module U1 are in communication connection with a serial communication port of the MCU, and a power-on end of the 4G communication module U1 is electrically connected with an output end of the MCU; the pin 46 of the 4G communication module U1 is electrically connected to the antenna.

Further preferably, the MCU monitoring system further comprises a storage unit (10), and the storage unit (10) is in communication connection with the MCU.

The utility model provides a pair of frequency sweep detection circuitry and intelligent acquisition appearance thereof for prior art, has following beneficial effect:

(1) The sweep frequency detection circuit of the scheme collects the sweep frequency in a step-by-step sweep frequency mode, and the whole frequency range is traversed, so that the driving signal provided by the MCU can change the output voltage and the voltage frequency of the excitation power supply unit, and the sweep frequency excitation effect is achieved; subsequently, the return signal is processed through the sweep frequency response receiving unit and the signal conditioning unit, a pulse signal is output, a built-in counter of the MCU counts the rising edge or the falling edge, the number of the pulse signals corresponding to the return signal in a specified time period is obtained, and the frequency is estimated;

(2) The sweep frequency response receiving unit carries out second-order filtering on the return signal to remove clutter signals; the signal conditioning unit is used for carrying out waveform lifting and proportional amplification on the return signal, then comparing the return signal with a preset voltage to obtain an overturning signal, outputting a pulse signal, limiting the amplitude and inputting the pulse signal into the MCU;

(3) Under the condition that the sweep frequency detection circuit is integrated, the intelligent acquisition instrument further increases the adaptive acquisition function of different types of analog signals, and realizes the multiplexing of output channels through the channel selector, thereby reducing the use of devices, reducing the overall volume of equipment, improving the integration level of the equipment, and further setting the remote communication or local data storage function as required to improve the expansion performance of the equipment.

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 these drawings without creative efforts.

Fig. 1 is a block diagram of the frequency sweep detection circuit and its intelligent acquisition instrument;

fig. 2 is a wiring diagram of the excitation power supply unit of the sweep frequency detection circuit and the intelligent collection instrument thereof;

fig. 3 is a wiring diagram of the frequency sweep response receiving unit of the frequency sweep detection circuit and the intelligent acquisition instrument thereof of the present invention;

fig. 4 is a wiring diagram of the signal conditioning unit of the sweep frequency detection circuit and the intelligent acquisition instrument thereof;

FIG. 5 is a wiring diagram of the sweep frequency detection circuit and the MCU of the intelligent acquisition instrument thereof;

fig. 6 is a wiring diagram of the voltage signal collecting unit, the current signal collecting unit, the resistance signal collecting unit, the channel selector and the analog-to-digital conversion unit of the intelligent collecting instrument of the present invention;

fig. 7 is a wiring diagram of the communication unit of the intelligent acquisition instrument of the present invention;

fig. 8 is a wiring diagram of the storage unit of the intelligent acquisition instrument of the present invention;

fig. 9 is the utility model relates to a power enable circuit and level shift circuit's of intelligence collection appearance wiring diagram.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts all belong to the protection scope of the present invention.

As shown in fig. 1-5, in one aspect, the present invention provides a frequency sweep detection circuit, which includes a vibrating wire sensor, an excitation power supply unit 1, a frequency sweep response receiving unit 2, a signal conditioning unit 3, and an MCU;

the excitation power supply unit 1 is used for generating excitation voltage and inputting the excitation voltage into the vibrating wire sensor; the output end of the MCU is electrically connected with the excitation power supply unit 1, and the MCU selectively adjusts the excitation voltage and frequency; as can be seen from the figure, the HV CTL pin of the MCU controls on/off of the transistor Q7, so as to change the size of the sampling resistor of the constant current driving chip U13, and change the size of the output excitation voltage V JL. In addition, the triode Q9 is periodically switched on or switched off by the K JL pin of the MCU, so that the frequency of the excitation voltage V JL is consistent with the action period of the K JL pin, and when the action frequency of the K JL pin is consistent with the working frequency range of the vibrating wire sensor to be verified and is gradually improved, the function of sweeping the frequency excitation signal source is realized. The illustrated SOR is the signal source identification.

The sweep frequency response receiving unit 2 is used for receiving a return signal generated by the vibrating wire sensor; the input end of the sweep frequency response receiving unit 2 is electrically connected with the output end of the vibrating wire sensor, and the output end of the sweep frequency response receiving unit 2 is electrically connected with the input end of the signal conditioning unit 3; the sweep frequency response receiving unit 2 acquires a corresponding return signal from a coil of the vibrating wire sensor, and the return signal is subjected to amplitude limiting, direct-current component isolation and filtering to obtain a T FREE signal which is further sent to the signal conditioning unit 3 for conversion processing.

The signal conditioning unit 3 compares and amplitude-limits the alternating current component of the feedback signal to obtain a square wave signal, i.e., F SIG in fig. 4, and the signal conditioning unit 3 sends the square wave signal F SIG to a pin 29 in the MCU. And counting the number of square wave signals F SIG in a certain period by a counter arranged in the MCU, and correspondingly acquiring the vibration frequency of the vibrating wire sensor. The MCU in the scheme is preferably an STM32F103 series single chip microcomputer of an ideological semiconductor.

As shown in fig. 2, a wiring diagram of an excitation power supply unit is shown. Specifically, the excitation power supply unit 1 comprises a constant current driving chip U13, an MOS tube Q8, a triode Q7 and a triode Q8; the input end and the enabling end of the constant current driving chip U13 are electrically connected with a power supply VPOWER respectively; the output end of the constant current driving chip U13 is electrically connected with the anode of the diode D2, and the cathode of the diode D2 is electrically connected with one end of the resistor R18, one end of the capacitor C10, one end of the capacitor C11, one end of the resistor R32 and the source of the MOS transistor Q8 respectively; the other end of the resistor R18 is electrically connected with the feedback input end of the constant current driving chip U13, one end of the resistor R19 and one end of the resistor R23 respectively, and the other end of the resistor R19, the other end of the capacitor C10 and the other end of the capacitor C11 are grounded; the other end of the resistor R23 is electrically connected with a collector of the triode Q7, an emitter of the triode Q7 is grounded, and a base of the triode Q7 is electrically connected with an output end HV CTL of the MCU; the other end of the resistor R32 and the grid electrode of the MOS tube Q8 are electrically connected with the collector electrode of the triode Q9, and the drain electrode of the MOS tube Q8 is electrically connected with the input end of the vibrating wire sensor; the emitting electrode of the triode Q9 is grounded, and the base electrode of the triode Q9 is electrically connected with the output end K JL of the MCU; the MCU selectively conducts the triode Q7 or Q8, and changes the size or the frequency of the output voltage V JL of the constant current driving chip U13. The input voltage of the constant current driving chip U13 is VPOWER, the output voltage of the constant current driving chip U13 is related to the size of the sampling resistor connected to the pin FB, and when the triode Q7 is turned on, the sampling resistor of the constant current driving chip U13 is changed from R19 to a parallel combination of R19 and R23, which doubles the amplitude of the excitation voltage V JL. The MCU is internally provided with a PWM waveform generating function, so that stepping frequency sweeping can be carried out, a signal with specific frequency is output, and after the triode Q9 is conducted, the MOS tube Q8 is also conducted, so that the frequency of the output voltage V JL is consistent with the frequency output by the K JL, and the vibrating wire sensor is excited.

As shown in fig. 3, the sweep frequency response receiving unit 2 includes a first operational amplifier U5 and a zener diode DZ2; the output end of the vibrating wire sensor is electrically connected with one end of a resistor R35, the other end of the resistor R35 is electrically connected with the cathode of the voltage stabilizing diode DZ2, one end of a resistor R36, one end of a resistor R37 and one end of a capacitor C12 respectively, and the anode of the voltage stabilizing diode DZ2 is grounded; the other end of the capacitor C12 is electrically connected with one end of the resistor R38 and the inverting input end of the first operational amplifier U5; the other end of the resistor R36 is grounded, the other end of the resistor R37 is electrically connected with one end of the capacitor C13, and the other end of the capacitor C13 is electrically connected with the other end of the resistor R38 and the output end of the first operational amplifier U5; the non-inverting input end of the first operational amplifier U5 is electrically connected with one end of the capacitor C15, and the other end of the capacitor C15 is grounded; the output end of the first operational amplifier U5 is further electrically connected to one end of the capacitor C16, and the other end of the capacitor C16 is electrically connected to the input end of the signal conditioning unit 3. The sweep frequency response receiving unit 2 is used for acquiring a corresponding return signal from an induction coil of the vibrating wire sensor, and after amplitude limiting is carried out on the return signal through a voltage stabilizing tube DZ2, the return signal is grounded through an anode of the Z2; and the other end of the capacitor C12, one end of the resistor R38, and a second-order filter formed by the resistors R36, R37 and R38 and the peripheral resistors C12 and C13 perform polarity filtering treatment, and isolate a direct current component to obtain a TFRE signal.

As shown in fig. 4, the signal conditioning unit 3 includes a second operational amplifier U6, a third operational amplifier U7, and diodes D3 and D5; the output end of the sweep frequency response receiving unit 2 and one end of the resistor R39 are electrically connected with the non-inverting input end of the second operational amplifier U6, respectively, and the other end of the resistor R39 is electrically connected with the reference voltage VERF; one end of the resistor R40 is electrically connected with the inverting input end of the second operational amplifier U6 and one end of the resistor R41, the other end of the resistor R40 is electrically connected with one end of the capacitor C22, and the other end of the capacitor C22 is grounded; the other end of the resistor R41 is electrically connected with the output end of the second operational amplifier U6; the output end of the second operational amplifier U6 is also electrically connected to one end of the capacitor C23, the other end of the capacitor C23 is electrically connected to one end of the resistor R42, the other end of the resistor R42 is electrically connected to the inverting input end of the third operational amplifier U7 and one end of the resistor R43, respectively, and the other end of the resistor R43 is electrically connected to the output end of the third operational amplifier U7; the reference voltage VERF is also electrically connected with the non-inverting input end of the third operational amplifier U7; the output end of the third operational amplifier U7 is electrically connected with the input end of the MCU. The reference voltage VERF and the T FRE signals are superposed and then amplified by the second operational amplifier U6, the amplified signals are compared with the reference voltage VERF, and the third operational amplifier U7 and peripheral devices thereof form a subtracter. The following diodes D3 and D5 form a limiter circuit, the resistor R45 and the capacitor C24 form a filter, and the resulting limited and filtered waveform signal F SIG is fed to the pin 29 of the MCU. Therefore, the acquisition of the sweep frequency response signal is realized.

In addition, as shown in fig. 6-8 in combination with fig. 1, in order to meet the acquisition requirements of various types of sensing signals on site, the utility model also provides an intelligent acquisition instrument, which comprises a voltage signal acquisition unit 4, a current signal acquisition unit 5, a resistance signal acquisition unit 6, a channel selector 7 and an analog-to-digital conversion unit 8 besides the sweep frequency detection circuit; the output end of the voltage signal acquisition unit 4, the output end of the current signal acquisition unit 5 or the output end of the resistance signal acquisition unit 6 are respectively and correspondingly electrically connected with different input channels of the channel selector 7; the output end of the channel selector 7 is electrically connected with the input end of the analog-to-digital conversion unit 8, and the output end of the analog-to-digital conversion unit 8 is in communication connection with the MCU; the voltage signal acquisition unit 4 is selectively and electrically connected with a sensor for outputting a voltage signal; the current signal acquisition unit 5 is selectively and electrically connected with a sensor for outputting a current signal, and the resistance signal acquisition unit 6 is selectively and electrically connected with a sensor for outputting a resistance value change signal; the output end of the MCU is electrically connected with the channel selector 7, and the voltage signal acquisition unit 4, the current signal acquisition unit 5 or the resistance signal acquisition unit 6 is electrically connected with the analog-to-digital conversion unit 8 by selecting one channel selector 7. In order to simplify the circuit layout and improve the integration of the device, the analog signals of the voltage, current or resistance type are multiplexed by the same channel selector 7, converted into digital values by the analog-to-digital conversion unit 8 and sent to the MCU. The channel selector 7 selects which input channel is determined by the high/low level of the output of the MCU V CHANA, V CHANB, or V CHANC. The MCU may also determine what type of analog signal corresponds to the digital value input after the analog-to-digital conversion processing according to the current state of V CHANA, V CHANB, or V CHANC. The channel selector 7 selects NLAST4051DTR2G chip, which has 8 input channels and one output channel COM. The analog-to-digital conversion unit 8 is an ADC analog-to-digital conversion chip with serial output, and the analog-to-digital conversion unit 8 is directly connected to the SPI ports of the MCU, i.e., the pin 20, the pin 21, the pin 22, and the pin 23. If the sensor outputs digital quantity or TTL digital signals, the digital quantity or TTL digital signals can be in communication connection with a serial communication interface of the MCU through an RS485 interface or be directly and electrically connected with an input end of the MCU, the level of the RS485 is different from the level grade of the MCU, a level conversion chip such as a MAX3485 is required to perform level conversion, and details are not repeated herein.

Specifically, as shown in fig. 6, a wiring diagram of the voltage signal acquisition unit 4 is shown. The voltage signal acquisition unit 4 comprises a fourth operational amplifier U10 and a plurality of divider resistors; a sensor for outputting a voltage signal is electrically connected with one end of the resistor R47 and one end of the capacitor C28 respectively, the other end of the resistor R47 is electrically connected with one end of the resistor R48 and the non-inverting input end of the fourth operational amplifier U10 respectively, and the other end of the resistor R48 and the other end of the capacitor C28 are grounded; the inverting input end and the output end of the fourth operational amplifier U10 are electrically connected; the output end of the fourth operational amplifier U10 is electrically connected to one end of the voltage dividing resistor R49, the other end of the voltage dividing resistor R49 is electrically connected to one end of the voltage dividing resistor R50, one end of the capacitor C29 and the input channel 0 of the channel selector 7, and the other end of the capacitor C29 is grounded; the other end of the voltage dividing resistor R50 is electrically connected to one end of the voltage dividing resistor R51, one end of the capacitor C30, and the input channel 6 of the channel selector 7, and the other end of the voltage dividing resistor R51 and the other end of the capacitor C30 are both grounded. After a voltage signal VIN is filtered by a filter circuit composed of a resistor R47, a resistor R48 and a capacitor C28, the voltage signal VIN is sent to each voltage dividing resistor after being isolated by a fourth operational amplifier U10, the fourth operational amplifier U10 plays a role of a voltage follower, three voltage dividing resistors R49, R50 and R51 which are connected in series continuously form two-stage voltage division, the voltage dividing signals are respectively V1 SIG and V2 SIG and are respectively input into an input channel 0 and an input channel 6 of a channel selector 7, the two voltage dividing signals can realize the output of voltage sampling signals with two different ranges, and the voltage amplitude of the V1 SIG is greater than that of the V2 SIG.

The signal processing part of the current signal acquisition unit 5 and the voltage signal acquisition unit 4 have basically the same structure, and the difference is that the current signal acquisition unit 5 is additionally provided with an I/V link, and the subsequent voltage division link is only one stage. The current signal IIN is converted into a voltage signal through the precision resistor R61, and then sent to the budget amplifier U14 after passing through an RC filter circuit composed of resistors R60 and R61 and a capacitor C37, the budget amplifier U14 serves as a voltage follower to perform an isolation function, and then the voltage signal is divided by resistors R58 and R56 to obtain an I SIG signal, which is sent to the input channel 4 of the channel selector 7.

The resistance signal acquisition unit 6 comprises a fifth operational amplifier U11 and a sixth operational amplifier U12; the reference voltage signal is electrically connected to the non-inverting input terminal of the fifth operational amplifier U11, the inverting input terminal of the fifth operational amplifier U11 is electrically connected to the output terminal thereof, the output terminal of the fifth operational amplifier U11 is electrically connected to one end of the resistor R53, the other end of the resistor R53 is electrically connected to the sensor for outputting the resistance value change signal and the non-inverting input terminal of the sixth operational amplifier U12, the inverting input terminal of the sixth operational amplifier U12 is electrically connected to the output terminal thereof, and the output terminal of the sixth operational amplifier U12 is electrically connected to the input channel 2 of the channel selector 7. The reference voltage +2.5V is input into a fifth operational amplifier U11 through a resistor R52, the fifth operational amplifier U11 also functions as a voltage follower and plays a role in isolation, the output voltage signal is filtered by a capacitor C33 and limited by a voltage regulator tube DZ3 after being connected in parallel with a resistor R53 or a sensor output end RIN which outputs a resistance value change signal, and then is input into a sixth operational amplifier U12 for isolation, and an RC filter circuit composed of a resistor R54 and a capacitor C34 filters the output R SIG signal to an input channel 2 of a channel selector 7. Since the resistance value of the resistor R53 is fixed, the RIN signal is changed, and the voltage input to the sixth operational amplifier U12 is changed as a result of the parallel connection of the two signals, so as to indirectly obtain the magnitude of RIN.

As shown in fig. 7, in order to realize the remote communication function of the intelligent acquisition instrument, the intelligent acquisition instrument of the present solution further includes a communication unit 9, the communication unit 9 includes a 4G communication module U1, an SIM card and an antenna, and a pin 9, a pin 10, a pin 11 and a pin 12 of the 4G communication module U1 are electrically connected to contacts of the SIM card in a one-to-one correspondence manner; a pin 36 and a pin 37 of the 4G communication module U1 are in communication connection with a serial communication port of the MCU, and a power-on end of the 4G communication module U1 is electrically connected with an output end of the MCU; the pin 46 of the 4G communication module U1 is electrically connected to the antenna. The 4G communication module U1 adopts an AIR724UG chip which can communicate only by being supported by a SIM card, the communication interface is GSM TXDM and GSM RXDM, because the voltage level V GLOBAL of the 4G communication module U1 is 1.8V, serial port level conversion is needed when the MCU communication with the level 3.3V is carried out, a circuit below a figure 7 is a serial port level conversion circuit, when the GSM TXDM sends data to the MCU RXD, a triode Q6 is conducted, and the output level is pulled up; when the GSM RXDM receives the data of the MCU TXD, the voltage is reduced through the reverse breakdown of the diode D1 and then is pulled up to 1.8V by VGLOBAL. The power supply voltage of the 4G communication module U1 is about 3.8V, the diagram in the middle of fig. 7 is an LDO buck chip, and the output V4G voltage is supplied to the 4G communication module U1. In order to save energy consumption, the 4G communication module U1 may be set to a sleep/wake-up function, and the 4G communication module U1 may be started by pulling down the PWRKEY 4G MCU pin of the MCU for several seconds. And if the 4G communication module U1 needs to work for a long time, the PWRKEY of the 4G communication module U1 is grounded. The 4G communication module U1 depends on an operator network, the 4G communication module U1 can be replaced by an LoRa module according to actual needs, and the function of remote wireless transmission is also realized, which is not described again.

As shown in fig. 8, the intelligent collecting instrument further includes a storage unit 10, and the storage unit 10 is in communication connection with the MCU. The memory cell 10 of the present embodiment is a TF card, i.e. illustrated as J3, and its data transmission interface is connected to a +3.3V power supply through a pull-up resistor. For storing the locally measured corresponding AD converted digital quantities.

The scheme can work in a real-time mode, a timing automatic acquisition mode or an energy-saving mode and other states. When the intelligent acquisition instrument is in a real-time mode, after the current acquisition process of digital quantity, analog quantity V1 SIG, V2 SIG, I SIG and R SIG or frequency signal F SIG is finished, next acquisition process is carried out; when the intelligent acquisition instrument is in the timing automatic acquisition mode, the intelligent acquisition instrument wakes up corresponding signal processing equipment such as an excitation power supply unit 1, a sweep frequency response receiving unit 2 and a signal conditioning unit 3 or a voltage signal acquisition unit 4, a current signal acquisition unit 5, a resistance signal acquisition unit 6, a channel selector 7 and an analog-to-digital conversion unit 8 to acquire different types of signals at fixed intervals, and automatically closes an acquisition channel or a power supply corresponding to the equipment after acquisition is finished; when the intelligent acquisition instrument is in the energy-saving mode, the network connection function of the communication unit 9 can be closed when the intelligent acquisition instrument does not perform remote data transmission, and only the most basic equipment functions are reserved if the intelligent acquisition instrument finishes uploading and acquisition. Fig. 9 shows a start-up circuit of a power supply corresponding to a part of channels. The VPOWER0 serves as an external power supply of the device, and when the CHAN EN port of the MCU is enabled at a high level, the VPOWER power supply is provided to the constant current driving chip U13. If manual adjustment is needed on site, a matrix keyboard can be additionally arranged to be connected with the input end of the MCU, and the power supply and the input of the keyboard are enabled through a KEY ANN12V pin of the MCU. If the voltages used by part of the chips are different, if the channel selector 7 or the communication unit 9 needs a 5V power supply, and the MCU needs a 3.3V power supply, respectively, the two-stage voltage reduction chips are used for sequentially reducing VPOWER0 to 5V, and then reducing 5V to 3.3V. As shown in fig. 5, the MCU can obtain the voltage state of VPOWER according to the voltage dividing resistors R30 and R29. The MCU can also alarm for abnormalities through U5, namely a loudspeaker.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and should not be construed as limiting the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A frequency sweep detection circuit is characterized by comprising a vibrating wire sensor, an excitation power supply unit (1), a frequency sweep response receiving unit (2), a signal conditioning unit (3) and an MCU (microprogrammed control unit);

the excitation power supply unit (1) is used for generating excitation voltage and inputting the excitation voltage into the vibrating wire sensor; the output end of the MCU is electrically connected with the excitation power supply unit (1), and the MCU selectively adjusts the excitation voltage and frequency;

the sweep frequency response receiving unit (2) is used for receiving a return signal generated by the vibrating wire sensor; the input end of the sweep frequency response receiving unit (2) is electrically connected with the output end of the vibrating wire sensor, and the output end of the sweep frequency response receiving unit (2) is electrically connected with the input end of the signal conditioning unit (3); the sweep frequency response receiving unit (2) isolates the direct current component of the return signal;

2. A sweeping frequency detection circuit according to claim 1, characterized in that the excitation power supply unit (1) comprises a constant current driving chip U13, a MOS transistor Q8, a triode Q7 and a triode Q8; the input end and the enable end of the constant current driving chip U13 are electrically connected with a power supply VPOWER respectively; the output end of the constant current driving chip U13 is electrically connected with the anode of the diode D2, and the cathode of the diode D2 is electrically connected with one end of the resistor R18, one end of the capacitor C10, one end of the capacitor C11, one end of the resistor R32 and the source of the MOS transistor Q8 respectively; the other end of the resistor R18 is electrically connected with the feedback input end of the constant current driving chip U13, one end of the resistor R19 and one end of the resistor R23 respectively, and the other end of the resistor R19, the other end of the capacitor C10 and the other end of the capacitor C11 are grounded; the other end of the resistor R23 is electrically connected with a collector of the triode Q7, an emitter of the triode Q7 is grounded, and a base of the triode Q7 is electrically connected with an output end HV CTL of the MCU; the other end of the resistor R32 and the grid electrode of the MOS tube Q8 are electrically connected with the collector electrode of the triode Q9, and the drain electrode of the MOS tube Q8 is electrically connected with the input end of the vibrating wire sensor; the emitting electrode of the triode Q9 is grounded, and the base electrode of the triode Q9 is electrically connected with the output end K JL of the MCU; the MCU selectively conducts the triode Q7 or Q8, and changes the size or the frequency of the output voltage V JL of the constant current driving chip U13.

3. A swept frequency detection circuit as claimed in claim 2, wherein the swept frequency response receiving unit (2) comprises a first operational amplifier U5 and a zener diode DZ2; the output end of the vibrating wire sensor is electrically connected with one end of a resistor R35, the other end of the resistor R35 is electrically connected with the cathode of the voltage stabilizing diode DZ2, one end of a resistor R36, one end of a resistor R37 and one end of a capacitor C12 respectively, and the anode of the voltage stabilizing diode DZ2 is grounded; the other end of the capacitor C12 is electrically connected with one end of the resistor R38 and the inverting input end of the first operational amplifier U5; the other end of the resistor R36 is grounded, the other end of the resistor R37 is electrically connected with one end of the capacitor C13, and the other end of the capacitor C13 is electrically connected with the other end of the resistor R38 and the output end of the first operational amplifier U5; the non-inverting input end of the first operational amplifier U5 is electrically connected with one end of the capacitor C15, and the other end of the capacitor C15 is grounded; the output end of the first operational amplifier U5 is also electrically connected with one end of the capacitor C16, and the other end of the capacitor C16 is electrically connected with the input end of the signal conditioning unit (3).

4. A swept frequency detection circuit according to claim 3, characterized in that the signal conditioning unit (3) comprises a second operational amplifier U6, a third operational amplifier U7, diodes D3 and D5; the output end of the sweep frequency response receiving unit (2) and one end of a resistor R39 are electrically connected with the non-inverting input end of a second operational amplifier U6 respectively, and the other end of the resistor R39 is electrically connected with a reference voltage VERF; one end of the resistor R40 is electrically connected with the inverting input end of the second operational amplifier U6 and one end of the resistor R41, the other end of the resistor R40 is electrically connected with one end of the capacitor C22, and the other end of the capacitor C22 is grounded; the other end of the resistor R41 is electrically connected with the output end of the second operational amplifier U6; the output end of the second operational amplifier U6 is also electrically connected to one end of the capacitor C23, the other end of the capacitor C23 is electrically connected to one end of the resistor R42, the other end of the resistor R42 is electrically connected to the inverting input end of the third operational amplifier U7 and one end of the resistor R43, respectively, and the other end of the resistor R43 is electrically connected to the output end of the third operational amplifier U7; the reference voltage VERF is also electrically connected with the non-inverting input end of the third operational amplifier U7; the output end of the third operational amplifier U7 is electrically connected with the input end of the MCU.

5. An intelligent acquisition instrument, which is characterized by comprising a voltage signal acquisition unit (4), a current signal acquisition unit (5), a resistance signal acquisition unit (6), a channel selector (7), an analog-to-digital conversion unit (8) and a sweep frequency detection circuit according to any one of claims 1 to 4; the output end of the voltage signal acquisition unit (4), the output end of the current signal acquisition unit (5) or the output end of the resistance signal acquisition unit (6) are respectively and correspondingly electrically connected with different input channels of the channel selector (7); the output end of the channel selector (7) is electrically connected with the input end of the analog-to-digital conversion unit (8), and the output end of the analog-to-digital conversion unit (8) is in communication connection with the MCU; the voltage signal acquisition unit (4) is selectively and electrically connected with the sensor for outputting voltage signals; the current signal acquisition unit (5) is selectively and electrically connected with a sensor for outputting a current signal, and the resistance signal acquisition unit (6) is selectively and electrically connected with a sensor for outputting a resistance value change signal; the output end of the MCU is electrically connected with the channel selector (7), and the channel selector (7) selects the voltage signal acquisition unit (4), the current signal acquisition unit (5) or the resistance signal acquisition unit (6) to be electrically connected with the analog-to-digital conversion unit (8).

6. The intelligent acquisition instrument according to claim 5, wherein the voltage signal acquisition unit (4) comprises a fourth operational amplifier U10 and a plurality of divider resistors; a sensor for outputting a voltage signal is electrically connected with one end of the resistor R47 and one end of the capacitor C28 respectively, the other end of the resistor R47 is electrically connected with one end of the resistor R48 and the non-inverting input end of the fourth operational amplifier U10 respectively, and the other end of the resistor R48 and the other end of the capacitor C28 are grounded; the inverting input end and the output end of the fourth operational amplifier U10 are electrically connected; the output end of the fourth operational amplifier U10 is electrically connected to one end of the voltage dividing resistor R49, the other end of the voltage dividing resistor R49 is electrically connected to one end of the voltage dividing resistor R50, one end of the capacitor C29 and the input channel 0 of the channel selector (7), and the other end of the capacitor C29 is grounded; the other end of the divider resistor R50 is electrically connected to one end of the divider resistor R51, one end of the capacitor C30, and the input channel 6 of the channel selector (7), and the other end of the divider resistor R51 and the other end of the capacitor C30 are all grounded.

7. The intelligent acquisition instrument according to claim 5, characterized in that the resistance signal acquisition unit (6) comprises a fifth operational amplifier U11 and a sixth operational amplifier U12; the reference voltage signal is electrically connected with the non-inverting input end of the fifth operational amplifier U11, the inverting input end of the fifth operational amplifier U11 is electrically connected with the output end thereof, the output end of the fifth operational amplifier U11 is electrically connected with one end of the resistor R53, the other end of the resistor R53 is electrically connected with the sensor for outputting the resistance value change signal and the non-inverting input end of the sixth operational amplifier U12 respectively, the inverting input end of the sixth operational amplifier U12 is electrically connected with the output end thereof, and the output end of the sixth operational amplifier U12 is electrically connected with the input channel 2 of the channel selector (7).

8. The intelligent acquisition instrument according to claim 5, further comprising a communication unit (9), wherein the communication unit (9) comprises a 4G communication module U1, a SIM card and an antenna, and the pin 9, the pin 10, the pin 11 and the pin 12 of the 4G communication module U1 are electrically connected with the contacts of the SIM card in a one-to-one correspondence manner; a pin 36 and a pin 37 of the 4G communication module U1 are in communication connection with a serial communication port of the MCU, and a power-on end of the 4G communication module U1 is electrically connected with an output end of the MCU; the pin 46 of the 4G communication module U1 is electrically connected to the antenna.

9. The intelligent acquisition instrument according to claim 5, further comprising a storage unit (10), wherein the storage unit (10) is in communication connection with the MCU.