CN204924274U - Capacitive sensor's analogue means - Google Patents
Capacitive sensor's analogue means Download PDFInfo
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- CN204924274U CN204924274U CN201520751940.4U CN201520751940U CN204924274U CN 204924274 U CN204924274 U CN 204924274U CN 201520751940 U CN201520751940 U CN 201520751940U CN 204924274 U CN204924274 U CN 204924274U
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Abstract
The utility model provides a capacitive sensor's analogue means, includes main control unit and at least one electric capacity simulator. Main control unit and upper computer connection, be suitable for with the user through the emulation capacitance value of host computer setting forward to the electric capacity simulator, the electric capacity simulator with main control unit connects, be suitable for according to drive signal with the emulation capacitance value produces the emulation signal, the frequency of emulation signal with drive signal's frequency is the same, the range of emulation signal is vin (Cs cr), and wherein, cs does the emulation capacitance value, vin does drive signal's range, cr is predetermined reference capacitance value. The embodiment of the utility model provides a capacitive sensor's analogue means improves the simulated result precision, the cost is reduced.
Description
Technical field
The utility model relates to technical field of capacitance sensor, particularly a kind of analogue means of capacitive transducer.
Background technology
When measuring non-electrical amount by electrical measuring method, first tested non-electrical amount must be converted to electrical quantities and then carry out showing or record.Be called as sensor according to the relevant conversion equipment that the feature of the non-electrical amount of difference is designed to, and the sensor tested mechanical quantity (such as displacement, power, speed etc.) being converted to capacitance variations is called as capacitive transducer.Capacitive transducer has that structure is simple, highly sensitive, dynamic response realizes the features such as non-cpntact measurement soon, easily, can be used for many occasions that the measurement means such as laser method, supercritical ultrasonics technology can not complete.From the angle of energy conversion, capacitive transducer is passive sensor, thus needs, by driving source and testing circuit, the capacitance change of capacitive transducer is converted to the voltage variety of output voltage.
Fig. 1 is the structural representation of the detection system of common a kind of capacitive transducer, described detection system comprises driving source U10, capacitive transducer group 10, change-over switch K10 and testing circuit, wherein, described capacitive transducer group comprises multiple capacitive transducer being distributed in position to be measured, and described testing circuit comprises operational amplifier A 10, feedback capacity C10 and input resistance R10.Concrete annexation in described detection system between each device as shown in Figure 1, does not repeat them here.When carrying out mechanical quantity detection, provide pumping signal by described driving source U10.By changing the capacitive transducer that described change-over switch K10 connects, the capacitance change of each capacitive transducer is converted to the voltage variety of output voltage Vout by described testing circuit successively.Because the corresponding relation between mechanical quantity to be measured and described output voltage Vout is known, the magnitude of voltage according to described output voltage Vout can obtain mechanical quantity to be measured.
The equivalent capacity of capacitive transducer is different, also different on the impact of described testing circuit, thus needs to simulate capacitive transducer.Artificial capacitor working sensor is carried out by the external adjustable precision capacitance of described testing circuit in prior art, but due to the capacitance of adjustable precision capacitance very little (being generally pico farad level), analog result is subject to distributed capacitance impact and the external condition interference of circuit, and the capacitance variation scope of adjustable precision capacitance is little, in simulation process, rely on manual adjustments to change the capacitance of adjustable precision capacitance, above-mentioned various factors causes the precision of analog result very low.Further, adjustable precision capacitance cost is also high.
Utility model content
To be solved in the utility model is adopt the adjustable problem that precision capacitance artificial capacitor sensor cost is high, analog result precision is low.
For solving the problem, the utility model provides a kind of analogue means of capacitive transducer, comprises master controller and at least one capacitance simulator; Described master controller is connected with host computer, and the emulation capacitance be suitable for user is arranged by host computer is forwarded to described capacitance simulator; Described capacitance simulator is connected with described master controller, be suitable for producing simulate signal according to pumping signal and described emulation capacitance, the frequency of described simulate signal is identical with the frequency of described pumping signal, the amplitude of described simulate signal is Vin × (Cs ÷ Cr), wherein, Cs is described emulation capacitance, and Vin is the amplitude of described pumping signal, and Cr is default reference capacitance value.The analogue means of the capacitive transducer that the utility model embodiment provides, the variation relation of the corresponding electric capacity of the change based on voltage, uses electronic technology simulation and the Changing Pattern of actual physics capacitor equivalent, capacitance change is converted to voltage variety.User arranges different emulation capacitances by host computer, can the capacitance variations of continuous analog wide region.The change fast response time, the capacitance that emulate capacitance in analogue means are stablized, and the resolution of electric capacity can reach 1pF, improves analog result precision, reduces the cost of simulating capacitive transducer.
Optionally, described capacitance simulator comprises from controller, at least one analog input channel and at least one analog output channel; Described analog input channel is connected with driving source, is suitable for carrying out analog-to-digital conversion process to obtain the first digital signal to described pumping signal; Describedly to be connected with described analog input channel and described master controller from controller, to be suitable for carrying out digital multiplication process to obtain the second digital signal to described first digital signal and described emulation capacitance; Described analog output channel with described from controller be connected be suitable for described second digital signal carry out signal export nurse one's health adaptive to obtain described simulate signal.
Optionally, described analog input channel comprises analog to digital converter.
Optionally, described analog output channel comprises digital to analog converter, bandpass filter, output interface circuit and reference capacitance, and described reference capacitance is suitable for providing described reference capacitance value; Described digital to analog converter is connected from controller with described, is suitable for carrying out digital-to-analog conversion process to obtain the first simulating signal to described second digital signal; Described bandpass filter is connected with described digital to analog converter, is suitable for carrying out bandpass filtering treatment to obtain the second simulating signal to described first simulating signal; Described output interface circuit is connected with described bandpass filter, is suitable for amplifying described second simulating signal and driving force strengthens process to obtain the 3rd simulating signal; One end of described reference capacitance is suitable for receiving described 3rd simulating signal, and the other end of described reference capacitance is suitable for exporting described simulate signal.
Optionally, described output interface circuit comprises operational amplifier, phase compensation electric capacity, the first resistance and the second resistance; The in-phase input end of described operational amplifier is suitable for receiving described second simulating signal, the inverting input of described operational amplifier connects one end of described phase compensation electric capacity and one end of described first resistance, the output terminal of described operational amplifier connects the other end of described phase compensation electric capacity and one end of described second resistance, and the other end of described first resistance connects the other end of described second resistance and is suitable for exporting described 3rd simulating signal.By arranging described output interface circuit, the driving force of circuit can be improved, adapting to different loads demand.
Optionally, described reference capacitance is plasticon electric capacity.
Optionally, described master controller is connected with host computer by USB interface.
Compared with prior art, the utility model has the following advantages:
The analogue means of the capacitive transducer that the utility model provides, use electronic technology simulation and the Changing Pattern of actual physics capacitor equivalent, can merge with Auto-Test System, improve the driving force of circuit, test signal be not vulnerable to external signal interference, stability and simulation result precision high.Use advanced control technology, make analogue means can adapt to the simulation test requirement of the capacitive transducer of requirements at the higher level.
Accompanying drawing explanation
Fig. 1 is the structural representation of the detection system of common a kind of capacitive transducer;
Fig. 2 is the testing circuit figure of capacitive transducer;
Fig. 3 is a kind of equivalent circuit diagram of testing circuit shown in Fig. 2;
Fig. 4 is the another kind of equivalent circuit diagram of testing circuit shown in Fig. 2;
Fig. 5 is the structural representation of the analogue means of the capacitive transducer of the utility model embodiment;
Fig. 6 is the structural representation of the analog output channel of the utility model embodiment;
Fig. 7 is the circuit diagram of the output interface circuit of the utility model embodiment.
Embodiment
Fig. 2 is the testing circuit figure of capacitive transducer.Driving source U20 is applied on capacitive transducer, amplitude is provided to be the pumping signal of Vin, the electric capacity C21 of the testing circuit Detection capacitance sensor be made up of operational amplifier A 20, feedback capacity C20 and input resistance R20 changes, and generation amplitude is the output signal of Vout.Relation between the amplitude Vout of output signal and the amplitude Vin of pumping signal can be expressed as:
Vout=-Vin × (C21 ÷ C20) equation (1)
Because the amplitude Vin of pumping signal and the electric capacity C21 of capacitive transducer is variable, in the two, any one changes and the amplitude Vout of output signal all can be caused to change.
The amplitude Vin of pumping signal is regarded as constant, the electric capacity C21 of capacitive transducer regards variable as, Fig. 3 is a kind of equivalent circuit diagram of testing circuit shown in Fig. 2, and in figure, each relation is expressed as:
Δ Vout=-Vin × (Δ Ci ÷ C20) equation (2)
Wherein, Δ Vout is the changes in amplitude amount of output signal, and Δ Ci is capacitance change.The amplitude Vin of pumping signal is regarded as variable, the electric capacity C21 of capacitive transducer regards constant as, Fig. 4 is the another kind of equivalent circuit diagram of testing circuit shown in Fig. 2, and in figure, each relation is expressed as:
Δ Vout=-Δ Vi × (Cin ÷ C20) equation (3)
Wherein, Δ Vi is the changes in amplitude amount of pumping signal, and Cin is fixed capacity.
Can be drawn by the above analysis to Fig. 3 and Fig. 4: make Fig. 4 can the function of alternate figures 3, the Δ Vout namely in equation (2) and equation (3) is equal, meets following equation:
Vin × Δ Ci=Δ Vi × Cin equation (4)
Then in the diagram capacitance simulator output can the change of electric capacity of artificial capacitor sensor on the impact of electric signal.Derived by equation (4) and obtain:
Δ Vi=Vin × (Δ Ci ÷ Cin) equation (5)
Equation (5) has reflected the variation relation of the corresponding electric capacity of the change of voltage, is converted to voltage variety by capacitance change.Based on equation (5), the utility model embodiment provides the analogue means of the capacitive transducer shown in a kind of Fig. 5, and the analogue means of described capacitive transducer comprises master controller 51 and at least one capacitance simulator.In the present embodiment, to comprise capacitance simulator 52 and capacitance simulator 53 is described.
Particularly, described master controller 51 is suitable for controlling each capacitance simulator and communicates with host computer 50, and the emulation capacitance that user is arranged by described host computer 50 is forwarded to each capacitance simulator.Further, described master controller 51 is connected with described host computer 50 by USB interface, and described host computer 50 is computing machine, and user can by keyboard or touch-screen input emulation capacitance.Described master controller 51 can be single-chip microcomputer or FPGA, for directly controlling each capacitance simulator, obtains the duty of each capacitance simulator.Each capacitance simulator is connected with described master controller 51, be suitable for producing simulate signal according to pumping signal and described emulation capacitance, the frequency of described simulate signal is identical with the frequency of described pumping signal, the amplitude of described simulate signal is Vin × (Cs ÷ Cr), wherein, Cs is described emulation capacitance, and Vin is the amplitude of described pumping signal, and Cr is default reference capacitance value.
The analogue means of the capacitive transducer that the utility model embodiment provides, the variation relation of the corresponding electric capacity of the change based on voltage, uses electronic technology simulation and the Changing Pattern of actual physics capacitor equivalent, capacitance change is converted to voltage variety.User arranges different emulation capacitances by host computer, can the capacitance variations of continuous analog wide region.Adopt the analogue means of the capacitive transducer of the utility model embodiment, achieve the simulation of 5pF ~ 450pF electric capacity.Further, the change fast response time, the capacitance that emulate capacitance in analogue means are stablized, and the resolution of electric capacity can reach 1pF, improves analog result precision, reduces the cost of simulating capacitive transducer.
Below in conjunction with embodiment and accompanying drawing, to the detailed description further of the utility model do, but embodiment of the present utility model is not limited thereto.
The utility model embodiment provides a kind of concrete structure of capacitance simulator, and described capacitance simulator comprises from controller, at least one analog input channel and at least one analog output channel.Continue with reference to figure 5, in the present embodiment, comprise an analog input channel for each capacitance simulator and an analog output channel is described.Described capacitance simulator 52 comprises from controller 521, analog input channel 522 and analog output channel 523, and described capacitance simulator 53 comprises from controller 531, analog input channel 532 and analog output channel 533.Because described capacitance simulator 52 is identical with described capacitance simulator 53 structure, be only described for described capacitance simulator 52 below.
Particularly, described analog input channel 522 and driving source and to be describedly connected from controller 521, be suitable for carrying out analog-to-digital conversion process to obtain the first digital signal to described pumping signal, described first digital signal be sent to described from controller 521.Further, described analog input channel 522 comprises analog to digital converter.Describedly to be connected from controller 521 with described master controller 51, receive described emulation capacitance from described master controller 51, receive described first digital signal from described analog input channel 522, be suitable for carrying out digital multiplication process to obtain the second digital signal to described first digital signal and described emulation capacitance, namely the amplitude of described second digital signal equals the amplitude of described first digital signal and the product of described emulation capacitance, and described second digital signal is sent to described analog output channel 523.Described can be fpga chip from controller 521, such as, can be the EP3C25F324 of ALTERA company.Those skilled in the art know and how to adopt fpga chip to carry out digital multiplication process to described first digital signal and described emulation capacitance, do not repeat them here.Described analog output channel 523 is connected from controller 521 with described, is suitable for carrying out signal to described second digital signal and exports conditioning adaptation to obtain described simulate signal.It should be noted that, only comprise an analog input channel for a capacitance simulator in the present embodiment and an analog output channel is described, in fact each capacitance simulator can comprise multiple analog input channel and multiple analog output channel, simulate the work of multiple capacitive transducer simultaneously, improve emulation testing efficiency.
The utility model embodiment provides a kind of concrete structure of described analog output channel 523, and as shown in Figure 6, described analog output channel 523 comprises digital to analog converter 61, bandpass filter 62, output interface circuit 63 and reference capacitance CR.Described reference capacitance CR is suitable for providing described reference capacitance value, and namely the capacitance of described reference capacitance CR equals described reference capacitance value, and described reference capacitance value can be arranged according to the actual requirements, and the utility model embodiment is not construed as limiting this.
Particularly, described digital to analog converter 61 is connected from controller 521 with described, is suitable for carrying out digital-to-analog conversion process to obtain the first simulating signal to described second digital signal.For the capacitance simulator with multiple analog output channel, according to the digital to analog converter of dual-port, then every two analog output channels can share a digital to analog converter.Described bandpass filter 62 is connected with described digital to analog converter 61, is suitable for carrying out bandpass filtering treatment to obtain the second simulating signal to described first simulating signal.By bandpass filtering treatment, can high-frequency signal in filtering digital-to-analog conversion process.Described output interface circuit 63 is connected with described bandpass filter 62, is suitable for amplifying described second simulating signal and driving force strengthens process to obtain the 3rd simulating signal.One end of described reference capacitance CR is suitable for receiving described 3rd simulating signal, and the other end of described reference capacitance CR is suitable for exporting described simulate signal.In the present embodiment, described reference capacitance CR is plasticon electric capacity.Plasticon capacitance accuracy is high, temperature coefficient is little, and the change that can reduce temperature, on the impact outputed signal, ensures the stable and accurate of output signal.
The utility model embodiment provides a kind of concrete structure of described output interface circuit 63, and as shown in Figure 7, described output interface circuit 63 comprises operational amplifier A 1, phase compensation electric capacity C71, the first resistance R71 and the second resistance R72.Particularly, the in-phase input end of described operational amplifier A 1 is suitable for receiving described second simulating signal, namely the in-phase input end of described operational amplifier A 1 connects the output terminal of described bandpass filter 62, the inverting input of described operational amplifier A 1 connects one end of described phase compensation electric capacity C71 and one end of described first resistance R71, the output terminal of described operational amplifier A 1 connects the other end of described phase compensation electric capacity C71 and one end of described second resistance R72, the other end of described first resistance R71 connects the other end of described second resistance R72 and is suitable for exporting described 3rd simulating signal.The output interface circuit that the present embodiment provides, can improve the driving force of circuit, adapt to dissimilar loading demand.
The above; it is only preferred embodiment of the present utility model; not do any pro forma restriction to the utility model, every any simple modification, equivalent variations done above embodiment according to technical spirit of the present utility model, all falls within protection domain of the present utility model.
Claims (7)
1. an analogue means for capacitive transducer, is characterized in that, comprises master controller and at least one capacitance simulator;
Described master controller is connected with host computer, and the emulation capacitance be suitable for user is arranged by host computer is forwarded to described capacitance simulator;
Described capacitance simulator is connected with described master controller, be suitable for producing simulate signal according to pumping signal and described emulation capacitance, the frequency of described simulate signal is identical with the frequency of described pumping signal, the amplitude of described simulate signal is Vin × (Cs ÷ Cr), wherein, Cs is described emulation capacitance, and Vin is the amplitude of described pumping signal, and Cr is default reference capacitance value.
2. the analogue means of capacitive transducer according to claim 1, is characterized in that, described capacitance simulator comprises from controller, at least one analog input channel and at least one analog output channel;
Described analog input channel is connected with driving source, is suitable for carrying out analog-to-digital conversion process to obtain the first digital signal to described pumping signal;
Describedly to be connected with described analog input channel and described master controller from controller, to be suitable for carrying out digital multiplication process to obtain the second digital signal to described first digital signal and described emulation capacitance;
Described analog output channel is connected from controller with described, is suitable for carrying out signal to described second digital signal and exports conditioning adaptation to obtain described simulate signal.
3. the analogue means of capacitive transducer according to claim 2, is characterized in that, described analog input channel comprises analog to digital converter.
4. the analogue means of capacitive transducer according to claim 2, is characterized in that, described analog output channel comprises digital to analog converter, bandpass filter, output interface circuit and reference capacitance, and described reference capacitance is suitable for providing described reference capacitance value;
Described digital to analog converter is connected from controller with described, is suitable for carrying out digital-to-analog conversion process to obtain the first simulating signal to described second digital signal;
Described bandpass filter is connected with described digital to analog converter, is suitable for carrying out bandpass filtering treatment to obtain the second simulating signal to described first simulating signal;
Described output interface circuit is connected with described bandpass filter, is suitable for amplifying described second simulating signal and driving force strengthens process to obtain the 3rd simulating signal;
One end of described reference capacitance is suitable for receiving described 3rd simulating signal, and the other end of described reference capacitance is suitable for exporting described simulate signal.
5. the analogue means of capacitive transducer according to claim 4, is characterized in that, described output interface circuit comprises operational amplifier, phase compensation electric capacity, the first resistance and the second resistance;
The in-phase input end of described operational amplifier is suitable for receiving described second simulating signal, the inverting input of described operational amplifier connects one end of described phase compensation electric capacity and one end of described first resistance, the output terminal of described operational amplifier connects the other end of described phase compensation electric capacity and one end of described second resistance, and the other end of described first resistance connects the other end of described second resistance and is suitable for exporting described 3rd simulating signal.
6. the analogue means of capacitive transducer according to claim 4, is characterized in that, described reference capacitance is plasticon electric capacity.
7. the analogue means of capacitive transducer according to claim 1, is characterized in that, described master controller is connected with host computer by USB interface.
Priority Applications (1)
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| CN201520751940.4U CN204924274U (en) | 2015-09-25 | 2015-09-25 | Capacitive sensor's analogue means |
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| CN201520751940.4U CN204924274U (en) | 2015-09-25 | 2015-09-25 | Capacitive sensor's analogue means |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105115535A (en) * | 2015-09-25 | 2015-12-02 | 成都华太测控技术有限公司 | Simulation apparatus of capacitance sensor |
| CN109507624A (en) * | 2018-11-07 | 2019-03-22 | 北京东方计量测试研究所 | A kind of method of capacitance simulator and artificial capacitor |
-
2015
- 2015-09-25 CN CN201520751940.4U patent/CN204924274U/en not_active Withdrawn - After Issue
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105115535A (en) * | 2015-09-25 | 2015-12-02 | 成都华太测控技术有限公司 | Simulation apparatus of capacitance sensor |
| CN105115535B (en) * | 2015-09-25 | 2017-06-09 | 成都华太测控技术有限公司 | The analogue means of capacitance sensor |
| CN109507624A (en) * | 2018-11-07 | 2019-03-22 | 北京东方计量测试研究所 | A kind of method of capacitance simulator and artificial capacitor |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
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| AV01 | Patent right actively abandoned |
Granted publication date: 20151230 Effective date of abandoning: 20170609 |