CN201006963Y

CN201006963Y - Bridge type capacity transducer circuit

Info

Publication number: CN201006963Y
Application number: CNU200620042369XU
Authority: CN
Inventors: 李锡放
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-06-02
Filing date: 2006-06-02
Publication date: 2008-01-16
Anticipated expiration: 2016-06-02

Abstract

Disclosed is a bridge type capacitance-type sensor circuit which comprises four arms comprising an inductance L1, an inductance L2, a capacitor C1 and a capacitor C2, having the characteristics that wherein one capacitor arm is connected with an electric adjusting capacitor CX, the capacitance of the capacitor CX is controlled by a microprocessor. The capacitor CX is a circuit of capisters or circuit of capacitor set controlled by electronic switch, or a programmable capacitor component.

Description

A kind of bridge-type capacity sensor circuit

Technical field

The utility model belongs to the field that capacitance type sensor is used in weaving detection of electrons field, the particularly dried instrument of bar etc.

Background technology

Weaving such as the dried instrument of bar, electronic yarn clearer detection of electrons class device generally uses capacitance type sensor.The self capacity of this class capacitance type sensor is less, generally has only several pico farads, and when built-up circuit, distribution capacity, stray capacitance and manufacturing and rigging error all can not be ignored.In order to obtain correct initialization point, need adjust bridge circuit.These in adjusting important one be adjustment to the electric bridge capacitance.Method of adjustment in the past is:

1. tunable capacitor adjustment;

2. fixed capacity adjustment;

3. the wiring capacitance adjustment of printed board.

Above method of adjustment can be summed up as mechanical adjustment, must be by manually finishing.Along with development of electronic technology, late-class circuit has adopted the intelligent circuit of microprocessor control mostly, but uncontrollable to the artificial prime bridge circuit of adjusting of needs.

The utility model content

The purpose of this utility model provides the circuit that a kind of prime bridge circuit at the bridge-type capacitance sensor is adjusted capacitance, and its value of adjusting electric capacity can be controlled by microprocessor.

For solving the problems of the technologies described above, the technical solution of the utility model is:

A kind of bridge-type capacity sensor circuit is formed four arms of electric bridge by inductance L 1, L2 and capacitor C1, C2, and wherein electric capacity one knee-joint has the capacitor C X that electricity is adjusted, and the capacitance of capacitor C X can be controlled by microprocessor.

Described capacitor C X is that electric capacity one arm, the series connection that inserts electric bridge in parallel inserts one of two kinds of connections of electric capacity one arm of electric bridge.

Described capacitor C X is made up of varactor D, resistance R 1, D/A circuit U 2; D/A circuit U 2 is accepted microprocessor control, output-controlled DC voltage by bus B US; This voltage is added on the varactor D by resistance R 1 as the reverse bias voltage of varactor D; By changing the output voltage values of D/A circuit U 2, in the capacitance of two end CP, the CM of described capacitor C X acquisition by the variation of microprocessor control.

Described capacitor C X by switches set K0, K1, K2 ..., KN, controller U3, capacitor group Cp0, Cp1, Cp2 ..., CpN forms, controller U3 accepts microprocessor control by bus B US, by gauge tap group K0, K1, K2 ..., KN conducting combination, obtain capacitance at two end CP, the CM of described capacitor C X by the variation of microprocessor control.

Described switches set K0, K1, K2 ..., KN is one of electronic switch, relay contact.

Described capacitor C X is an electrically programmable capacitor devices U4, and electrically programmable capacitor devices U4 accepts microprocessor control by bus B US, in the capacitance of two end CP, the CM of described capacitor C X acquisition by the variation of microprocessor control.

One arm of the minimum access electric bridge of described capacitor C X also can insert two arms, three arms, four arms of electric bridge; Equally, capacitor C X of minimum access in the arm also can insert a plurality of simultaneously therein.

If described capacitor C X inserts electric bridge in the mode more than, then the mode of Jie Ruing is one of series, parallel and connection in series-parallel combination connection.

The access of described capacitor C X does not influence four knee-joints of electric bridge and goes into other resistive, perceptual element or adjustment circuit adjusted.

Described capacitor C X is not limited only to by microprocessor control, also can be by other Digital Circuit Control.

The good effect that adopts the technical program to produce is: the electrical quantity that can be adjusted the bridge-type capacitance sensor by microprocessor automatically.

Description of drawings

Below in conjunction with accompanying drawing the specific embodiment of the present utility model is described in further detail.

Fig. 1 is the embodiment whole electrical schematic diagram of uniting and adjustment in the lump;

Fig. 2 is that electrical schematic diagram is adjusted in embodiment two series connection;

Fig. 3 is the electrical schematic diagram of embodiment three;

Fig. 4 is the electrical schematic diagram of embodiment four;

Fig. 5 is the electrical schematic diagram of embodiment five.

The specific embodiment

Fig. 1 is the embodiment whole electrical schematic diagram of uniting and adjustment in the lump, forms four arms of electric bridge by inductance L 1, L2 and capacitor C1, C2, and OUT is the electric bridge output, electric capacity one arm and be connected with the capacitor C X of electricity adjustment wherein, and the capacitance of capacitor C X can be controlled by microprocessor.

By electrical bridge principle as can be known, when L1=L2, if C1=C2+CX, bridge balance.Therefore as adjusting element CX, just can play the effect of adjusting electric bridge on the electric capacity support arm therein, be not limited to certainly at C1 support arm or C2 support arm; Can certainly insert two arms, three arms, four arms of electric bridge simultaneously.

Fig. 2 is that electrical schematic diagrams are adjusted in embodiment two series connection, forms four arms of electric bridge by inductance L 1, L2 and capacitor C1, C2, and OUT is the electric bridge output, and wherein the series connection of electric capacity one arm is connected to the capacitor C X of electricity adjustment, and the capacitance of capacitor C X can be controlled by microprocessor.

According to electrical bridge principle, adjust element CX in parallel insert or series connection to insert all be feasible, but whether the DC level that will consider the CP end can influence electric bridge output OUT, therefore for the CX of embodiment three, inserts to well with series connection.

If insert electric bridge simultaneously with a plurality of adjustment element CX, then can there be different series connection to insert and access scheme in parallel, even can on a brachium pontis, series, parallel, connection in series-parallel combination simultaneously insert a plurality of adjustment element CX, all being that those skilled in the art can be expected naturally, is not the improvement to the technical program.In addition, core technology of the present utility model is to adjust element CX with the electricity of microprocessor control electric bridge, if also be connected to traditional tunable capacitor or other adjustment element simultaneously on electric bridge, is not the improvement to the technical program.

Fig. 3 is the electrical schematic diagram of embodiment three, and capacitor C X is made up of varactor D.Varactor is such device, and when its two end added reverse bias voltage, its capacitance reduced and increases with institute is alive.By D/A converting circuit of microprocessor control, produce the voltage of controlling varactor by this circuit, just can obtain required capacitor C X.

Capacitor C X is made up of varactor D, resistance R 1, D/A circuit U 2; D/A circuit U 2 is accepted microprocessor control, output-controlled DC voltage by bus B US; This voltage is added on the varactor D by resistance R 1 as the reverse bias voltage of varactor D; By changing the output voltage values of D/A circuit U 2, obtain capacitance by the variation of microprocessor control at CP, CM two ends.

There are various D/A converting circuits to use, but will note finally being added to the bias voltage value of varactor D, should meet the transfiguration characteristic of varactor D.

Fig. 4 is the electrical schematic diagram of embodiment four, and capacitor C X is made up of switches set, capacitor group and control circuit.

Capacitor C X by switches set K0, K1, K2 ..., KN, controller U3, capacitor group Cp0, Cp1, Cp2 ..., CpN forms, controller U3 accepts microprocessor control by bus B US, by gauge tap group K0, K1, K2 ..., KN conducting combination, obtain capacitance at CP, CM two ends by the variation of microprocessor control.Bus B US connects microprocessor among the figure.Described switches set K0, K1, K2 ..., KN can be electronic switch, also can be relay contact.

Fig. 5 is the electrical schematic diagram of embodiment five, and capacitor C X is an electrically programmable capacitor devices U4, and electrically programmable capacitor devices (U4) is accepted microprocessor control by bus B US, in the capacitance of (CP, CM) two ends acquisition by the variation of microprocessor control.

In the statement of Fig. 3, Fig. 4, Fig. 5, the statement of " accepting microprocessor control by bus B US " is arranged.The most frequently used control scheme during microprocessor control is just controlled at present automatically, the professional and technical personnel knows, a lot of digital circuits can constitute the control circuit of effect same, PGA for example, FPGA, digital circuits such as CPLD can produce this class control circuit, no longer enumerate, and these circuit are not the improvement to the technical program too.

Because electric bridge is the known circuit that specific annexation is arranged, and insert the adjustment element in the electric bridge multiple connection is arranged, it also is known technology, therefore the statement of the technical program can not be confined to one or more and be fixedly coupled relation, but is expressed as the circuit of the electric position of the element CX of adjustment in electric bridge and realization CX electricity adjustment function more.

Claims

1. bridge-type capacity sensor circuit is formed four arms of electric bridge by inductance (L1, L2) and capacitor (C1, C2), and it is characterized in that: wherein electric capacity one knee-joint has the electric capacity (CX) that electricity is adjusted, and the capacitance of electric capacity (CX) can be controlled by microprocessor.

2. bridge-type capacity sensor circuit as claimed in claim 1 is characterized in that: described electric capacity (CX) inserts one of two kinds of connections of electric capacity one arm of electric bridge for electric capacity one arm, the series connection that inserts electric bridge in parallel.

3. bridge-type capacity sensor circuit as claimed in claim 1 is characterized in that: described electric capacity (CX) is made up of varactor (D), resistance (R1), D/A circuit (U2); D/A circuit (U2) is accepted microprocessor control, output-controlled DC voltage by bus (BUS); This voltage is added on the varactor (D) by resistance (R1) as the reverse bias voltage of varactor (D); By changing the output voltage values of D/A circuit (U2), obtain capacitance by the variation of microprocessor control at two ends (CP, CM) of described electric capacity (CX).

4. bridge-type capacity sensor circuit as claimed in claim 1, it is characterized in that: described electric capacity (CX) by switches set (K0, K1, K2 ..., KN), controller (U3), the capacitor group (C p 0, C p 1, C p 2 ..., C p N) form, controller (U3) is accepted microprocessor control by bus (BUS), by the gauge tap group (K0, K1, K2 ..., KN) the conducting combination, obtain capacitance at two ends (CP, CM) of described electric capacity (CX) by the variation of microprocessor control.

5. bridge-type capacity sensor circuit as claimed in claim 4 is characterized in that: described switches set (K0, K1, K2 ..., KN) be one of electronic switch, relay contact.

6. bridge-type capacity sensor circuit as claimed in claim 1, it is characterized in that: described electric capacity (CX) is an electrically programmable capacitor devices (U4), electrically programmable capacitor devices (U4) is accepted microprocessor control by bus (BUS), obtains capacitance by the variation of microprocessor control at two ends (CP, CM) of described electric capacity (CX).

7. bridge-type capacity sensor circuit as claimed in claim 1 is characterized in that: an arm of the minimum access electric bridge of described electric capacity (CX), also can insert two arms, three arms, four arms of electric bridge; Equally, an electric capacity of minimum access (CX) in the arm also can insert a plurality of simultaneously therein.

8. bridge-type capacity sensor circuit as claimed in claim 1 is characterized in that: described electric capacity (CX) is if insert electric bridge in the mode more than, and then the mode of Jie Ruing is one of series, parallel and connection in series-parallel combination connection.

9. bridge-type capacity sensor circuit as claimed in claim 1 is characterized in that: described electric capacity (CX) is not limited only to by microprocessor control, also can be by other Digital Circuit Control.