CN203287103U - Measuring circuit for vibration amplitude - Google Patents

Abstract

Disclosed in the utility model is a measuring circuit for a vibration amplitude. The measuring circuit comprises an integral compensation and adjustment circuit and a high-precision vibration amplitude conversion and adjustment circuit. The integral compensation and adjustment circuit includes an integral compensation circuit portion and an adjustment circuit portion, wherein the two portions are respectively formed by two operational amplifiers; and the high-precision vibration amplitude conversion and adjustment circuit includes a high-precision vibration amplitude conversion circuit portion and an adjustment circuit portion, wherein the two portions are respectively formed by two operational amplifiers. The provided measuring circuit has the high measuring precision and high stability; signals from vibration sensors of various types can be identified and the universal application of the equipment is improved. The provided measuring circuit is suitable for various types of vibration sensors like a vibration speed sensor, a piezoelectric type vibration sensor, and an eddy current sensor and the like.

Description

The vibration amplitude metering circuit

Technical field

The utility model relates to rotating machinery on-line monitoring field, is specifically related to a kind of high-precision circuit for the vibration amplitude measurement, is applicable to industrial overall machine vibration monitoring protection series instrument.

Background technology

Vibration amplitude is the main monitoring parameter of big-and-middle-sized rotating machinery such as steam turbine, generator, blower fan, water pump etc., it has directly reflected the Oscillation Amplitude size of equipment, be directly connected to the safety case of equipment, so the accuracy of vibration amplitude becomes extremely important in actual measurement.Existing vibration amplitude metering system is still undertaken by the traditional measurement circuit, and data precision is low, poor stability, causes phenomenons such as showing data fluctuations severity.

The utility model content

The purpose of this utility model is to overcome above-mentioned weak point, a kind of vibration amplitude metering circuit is provided, adopts high precision amplitude change-over circuit and compensation deals, improve the Stability and veracity of measuring, can identify simultaneously the signal of polytype vibration transducer, improve the compatibility of equipment.

The technical solution of the utility model is as follows:

A kind of vibration amplitude metering circuit, comprise integral compensation and Circuit tuning and the conversion of high precision amplitude and Circuit tuning;

described integral compensation and Circuit tuning comprise the first operational amplifier and the second operational amplifier, after the inverting input of the first operational amplifier series connection the first resistance and the first electric capacity as the input end of integral compensation and Circuit tuning, be connected to after the second resistance and the second Capacitance parallel connection between the inverting input and output terminal of the first operational amplifier, the in-phase input end of the first operational amplifier connects the 3rd drop-down resistance, the negative power end of the first operational amplifier connects the 3rd drop-down electric capacity and connection-12V voltage, the positive power source terminal of the first operational amplifier connects the 4th drop-down electric capacity and connection+12V voltage, the inverting input that connects the second operational amplifier after the output terminal of the first operational amplifier series connection the 5th electric capacity and the 4th resistance, the in-phase input end of the second operational amplifier connects the 5th drop-down resistance, the 6th resistance is connected between the inverting input and output terminal of the second operational amplifier, after the output terminal of the second operational amplifier series connection the 6th electric capacity as the output terminal of integral compensation and Circuit tuning,

described high precision amplitude conversion and Circuit tuning comprise the 3rd operational amplifier and four-operational amplifier, after the inverting input of the 3rd operational amplifier series connection the 7th resistance as the input end of the conversion of high precision amplitude and Circuit tuning, the in-phase input end of the 3rd operational amplifier connects the 8th drop-down resistance, the in-phase input end that connects the 3rd operational amplifier after adjustment end series connection the 9th resistance of the first adjustable resistance, two ends after the first adjustable resistance and voltage stabilizing diode parallel connection are connected respectively the tenth resistance and the 11 resistance that draws, the positive pole of the first diode, negative pole respectively with the inverting input of the 3rd operational amplifier, output terminal connects, output terminal series connection second diode of the 3rd operational amplifier, connect the in-phase input end of four-operational amplifier after the 12 resistance and the 13 resistance, the 14 resistance string is associated between the negative pole of the first diode cathode and the second diode, be connected with the 7th drop-down electric capacity between the 12 resistance and the 13 resistance, the inverting input of four-operational amplifier is connected with the 15 drop-down resistance, the 16 resistance be connected between the inverting input and output terminal of four-operational amplifier after the second adjustable resistance is connected, the adjustment end of the second adjustable resistance is connected with the output terminal of four-operational amplifier, the output terminal of four-operational amplifier connects an end of the 17 resistance, the other end of the 17 resistance connects the 8th drop-down electric capacity, and as the output terminal of the conversion of high precision amplitude and Circuit tuning,

The output terminal of described integral compensation and Circuit tuning is connected with the input end of described high precision amplitude conversion and Circuit tuning.

Useful technique effect of the present utility model is:

Vibration amplitude metering circuit provided by the utility model has very high measuring accuracy and stability, and this circuit goes for the vibration transducer of multi-signal type, such as vibrating speed sensors, piezoelectric vibration pickup, current vortex sensor etc.

The additional advantage of the utility model provides in embodiment description partly below, and part will become obviously from the following description, or by practice of the present utility model, recognize.

Description of drawings

Fig. 1 is integral compensation of the present utility model and Circuit tuning figure.

Fig. 2 is high precision amplitude conversion of the present utility model and Circuit tuning figure.

Embodiment

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

The utility model comprises integral compensation and Circuit tuning (Fig. 1) and the conversion of high precision amplitude and Circuit tuning (Fig. 2) two parts.The former output terminal and the latter's input end is interconnective, is same end.

As shown in Figure 1, integral compensation and Circuit tuning comprise operational amplifier LM064A, operational amplifier LM064B.After the inverting input resistance in series R1-C of operational amplifier LM064A and capacitor C 1-C as the input end Vi-C of integral compensation and Circuit tuning; Be connected between the inverting input and output terminal of operational amplifier LM064A after resistance R 2-C and capacitor C 3-C parallel connection; The in-phase input end of operational amplifier LM064A connects drop-down resistance R 3-C, the negative power end of operational amplifier LM064A connects drop-down capacitor C 4-C and connection-12V voltage, the positive power source terminal of operational amplifier LM064A connects drop-down capacitor C 5-C and connection+12V voltage, the inverting input of concatenation operation amplifier LM064B after the output terminal series capacitance C6-C of operational amplifier LM064A and resistance R 4-C.The in-phase input end of operational amplifier LM064B connects drop-down resistance R 6-C; Resistance R 7-C is connected between the inverting input and output terminal of operational amplifier LM064B; After the output terminal series capacitance C9-C of operational amplifier LM064B as the output end vo-1C of integral compensation and Circuit tuning.

As shown in Figure 2, the conversion of high precision amplitude and Circuit tuning comprise operational amplifier LM064C and operational amplifier LM064D.After the inverting input resistance in series R8-C of operational amplifier LM064C as the input end Vo-1C(of high precision amplitude conversion and Circuit tuning be Fig. 1 output end vo-1C), the in-phase input end of operational amplifier LM064C connects drop-down resistance R 9-C; Two ends after the in-phase input end of concatenation operation amplifier LM064C after the adjustment end resistance in series R10-C of adjustable resistance W1-C, adjustable resistance W1-C and voltage stabilizing diode DW1-C parallel connection are connected respectively resistance R 11-C and the resistance R 12-C that draws; The positive pole of diode D1-C, negative pole are connected with inverting input, the output terminal of operational amplifier LM064C respectively; The in-phase input end of concatenation operation amplifier LM064C after output terminal series diode D2-C, the resistance R 14-C of operational amplifier LM064C and resistance R 15-C; Resistance R 13-C is connected between the negative pole of diode D1-C positive pole and diode D2-C; Be connected with drop-down capacitor C 10-C between resistance R 14-C and resistance R 15-C.The inverting input of operational amplifier LM064C is connected with drop-down resistance R 16-C; Resistance R 17-C be connected between the inverting input and output terminal of operational amplifier LM064C after adjustable resistance W12-C connects, the adjustment end of adjustable resistance W12-C is connected with the output terminal of operational amplifier LM064C; The end of the output terminal contact resistance R20-C of operational amplifier LM064C, the other end of resistance R 20-C connects drop-down capacitor C 9-B, and as the output end vo-C of the conversion of high precision amplitude and Circuit tuning.

Principle of work of the present utility model is as follows:

By the vibrating speed sensors principle as can be known the voltage U i of vibrating speed sensors output be proportional to vibration velocity v, and the relation of vibration displacement D and vibration velocity v is: formula v=(2 π f/1000) * D, therefore will obtain the signal that vibration displacement (amplitude) is directly proportional, the speed pickup output voltage signal must pass through Integral Processing.But pure integration is because the offset voltage to amplifier itself, offset current carry out integration, and its output may be in complete state of saturation, causes dc shift.Therefore need to be on integrating capacitor C3-C resistance R 2-C in parallel, can produce the tributary feedback, reduce the dc shift of amplifier, and imbalance compensated.Resistance R 2-C resistance can not be got too large, otherwise inadequate to suppressing dc shift, affects precision; That gets is too little, can reduce the input resistance of integration, gets 100K in the embodiment circuit.Capacitor C 3-C generally is no more than 1 μ F, gets 0.33 μ F in the embodiment circuit.The integral compensation circuit is as shown in left-half in Fig. 1.In Fig. 1,

i _R1≈i _C3， $i_{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HDA00003246776000011.png"\; state="\{\{state\}\}">R</figure-callout>}1}=\frac{\mathrm{Ui}}{R1}$

${\mathrm{<figure-callout\; id="3"\; label="i\; C"\; filenames="HDA00003246776000011.png"\; state="\{\{state\}\}">i</figure-callout>}}_C=-C\frac{\mathrm{dUo}}{\mathrm{dt}}$

$\mathrm{Uo}=-\frac{1}{C}{\&Integral;}_0^1{i}_{\mathrm{<figure-callout\; id="3"\; label="c"\; filenames="HDA00003246776000011.png"\; state="\{\{state\}\}">c</figure-callout>}3}\mathrm{dt}$

$=-\frac{1}{C}{\&Integral;}_0^1\frac{\mathrm{<figure-callout\; id="1"\; label="Ui\; R"\; filenames="HDA00003246776000011.png"\; state="\{\{state\}\}">Ui</figure-callout>}}{R}\mathrm{dt}$

$=-\frac{1}{R1C}{\&Integral;}_0^1\mathrm{Uidt}$

If when Ui is step voltage, have

In addition, the integrating circuit back need to add a coupling capacitance C6-C, carries out every straight processing.Then signal is adjusted by operational amplifier, then every straight processing.Circuit tuning is as shown in right half part in Fig. 1.Amplifier in Fig. 2 is inverting amplifier, adjusts voltage gain to be:

$A_{\mathrm{VF}}=-\frac{R_{7-C}}{R_{4-C}}.$

Then, need to convert Integral Processing AC signal out to need d. c. voltage signal corresponding to peak value.Therefore, need to change the signal of previous processed with high precision amplitude change-over circuit.High precision amplitude change-over circuit is as shown in left-half in Fig. 2.Circuit in Fig. 2 is anti-phase type amplitude change-over circuit.Amplifier LM064C forms a differential amplifier circuit, and input signal is amplified and adjusts.D2-C is the half-wave detector diode, and C10-C is memory capacitance, and resistance R 8-C and R13-C form feedback circuit.Amplifier LM064C carries out anti-phase amplification to input signal, and when diode D2-C conducting, during diode D1-C cut-off, the output voltage that is amplified by amplifier LM064C charges to capacitor C 10-C by diode D2-C, makes Uo follow Ui; When diode D1-C conducting, during diode D2-C cut-off, capacitor C 10-C and amplifier LM064C isolation, Uo keeps the crest voltage of Ui.Therefore, as long as output does not wait with input voltage, degenerative effect is constantly output voltage to be proofreaied and correct, until both equate.So the conducting resistance of diode D2-C, the imbalance of amplifier LM064C and the factors such as drift, common-mode error are weakened greatly on the impact of precision, be that output voltage changes with input voltage, Here it is, and this amplitude change-over circuit has high-precision reason.Circuit nonlinear distortion D can be expressed as:

$D=-\frac{D^{\&prime;}}{1+K1F},$

In formula, D ' is the nonlinear distortion of diode detector; K1 is the enlargement factor of amplifier LM064C, K1=-R _D1/ R _8-CF is feedback factor; RD1 is the value of the anti-phase resistance of diode D1-C.

When diode D1-C works in 70 ℃ of junction temperatures, when reverse voltage is 10V, from family curve, can try to achieve RD1=150M Ω.

$K1=-\frac{R_{D1}}{R_{8-C}}=-\frac{150000}{30}=-5000$

Feedback factor F can be expressed as:

$F\&ap;-\frac{R_{8-C}}{R_{13-C}}=-\frac{30}{62}=-0.48$

Nonlinear distortion is:

$D\&ap;-\frac{D^{\&prime;}}{1+K1F}=\frac{D^{\&prime;}}{1+5000\&times;0.48}\&ap;\frac{D^{\&prime;}}{2400}$

As seen, in detector diode access backfeed loop, be that nonlinear distortion drops to original 1/2400.

Also to point out, general simple diode wave detector, when signal voltage during less than 0.6V (silicon diode pressure drop) can't carry out detection.And the minimum detecting circuit that this wave detector allows dwindles K1 doubly, and namely minimum detecting circuit Umin is:

$U_{\min }=\frac{0.6}{\left|\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="HDA00003246776000011.png"\; state="\{\{state\}\}">K</figure-callout>}1\right|}=\frac{0.6}{5000}=0.12\left(\mathrm{mV}\right)$

Memory capacitance C10-C should select the large electric capacity of bleeder resistance, as polystyrene, polypropylene, micadon.

Choosing of the numerical value of capacitor C 10-C is also very important.When too small, charging rate is fast, but, because amplifier LM064C and feedback loop speed do not catch up with, causes leading error, and discharge simultaneously is also very fast, causes and keeps error; And when excessive, above two kinds of errors will reduce, but often can not be charged to ceiling voltage, perhaps the velocity of discharge of electric capacity can not be followed the envelope variation of input signal amplitude fully, this all will bring new error.Thereby the selection of electric capacity should determine according to actual conditions, gets 47 μ F electrochemical capacitors in the embodiment circuit.

The upper frequency limit value of input signal is determined by bandwidth and the ascending velocity of operational amplifier, when being used for high frequency, should select the larger operational amplifier of gain bandwidth product and ascending velocity.

When if rectified signal is positive polarity voltage, as long as two diodes reversal connection simultaneously of circuit.

Finally, the direct current signal that the vibration displacement of handling well (amplitude) is corresponding is adjusted through operational amplifier LM064D, and rectifying and wave-filtering, obtaining can be for the signal of A/D module samples.Circuit tuning is as shown in right half part in Fig. 2.

Above-described components and parts are commercial goods, and the components and parts model in embodiment can see table:

Main components table in Fig. 1, Fig. 2:

Sequence number	The components and parts code name	The components and parts type	Component parameter or model
				1	LM064A	Operational amplifier	?
2	LM064B	Operational amplifier	?
				3	LM064C	Operational amplifier	?
4	LM064D	Operational amplifier	?
				5	R2-C	Resistance	100K
6	C3-C	Electric capacity	0.33μF
				7	D1-C、D2-C	Diode	?
8	C10-C	Electric capacity	47 μ F electrochemical capacitors

Above-described is only preferred implementation of the present utility model, and the utility model is not limited to above embodiment.Be appreciated that those skilled in the art directly derive or associate under the prerequisite that does not break away from basic conception of the present utility model other improvement and variation, within all should thinking and being included in protection domain of the present utility model.

Claims (1)

1. a vibration amplitude metering circuit, is characterized in that, comprises integral compensation and Circuit tuning (A) and the conversion of high precision amplitude and Circuit tuning (B);

described integral compensation and Circuit tuning (A) comprise the first operational amplifier (LM064A) and the second operational amplifier (LM064B), inverting input series connection first resistance (R1-C) of the first operational amplifier (LM064A) and the rear input end as integral compensation and Circuit tuning of the first electric capacity (C1-C), be connected between the inverting input and output terminal of the first operational amplifier (LM064A) after the second resistance (R2-C) and the second electric capacity (C3-C) parallel connection, the in-phase input end of the first operational amplifier (LM064A) connects drop-down the 3rd resistance (R3-C), the negative power end of the first operational amplifier (LM064A) connects drop-down the 3rd electric capacity (C4-C) and connection-12V voltage, the positive power source terminal of the first operational amplifier (LM064A) connects drop-down the 4th electric capacity (C5-C) and connection+12V voltage, output terminal series connection the 5th electric capacity (C6-C) of the first operational amplifier (LM064A) and the rear inverting input that connects the second operational amplifier (LM064B) of the 4th resistance (R4-C), the in-phase input end of the second operational amplifier (LM064B) connects drop-down the 5th resistance (R6-C), the 6th resistance (R7-C) is connected between the inverting input and output terminal of the second operational amplifier (LM064B), the rear output terminal as integral compensation and Circuit tuning of the output terminal of the second operational amplifier (LM064B) series connection the 6th electric capacity (C9-C),

described high precision amplitude conversion and Circuit tuning (B) comprise the 3rd operational amplifier (LM064C) and four-operational amplifier (LM064D), the rear input end as the conversion of high precision amplitude and Circuit tuning of inverting input series connection the 7th resistance (R8-C) of the 3rd operational amplifier (LM064C), the in-phase input end of the 3rd operational amplifier (LM064C) connects drop-down the 8th resistance (R9-C), the in-phase input end that connects the 3rd operational amplifier (LM064C) after adjustment end series connection the 9th resistance (R10-C) of the first adjustable resistance (W1-C), two ends after the first adjustable resistance (W1-C) and voltage stabilizing diode (DW1-C) parallel connection are connected respectively the tenth resistance (R11-C) and the 11 resistance (R12-C) that draws, the positive pole of the first diode (D1-C), negative pole respectively with the inverting input of the 3rd operational amplifier (LM064C), output terminal connects, output terminal series connection second diode (D2-C) of the 3rd operational amplifier (LM064C), the 12 resistance (R14-C) and the rear in-phase input end that connects four-operational amplifier (LM064C) of the 13 resistance (R15-C), the 14 resistance (R13-C) is connected between the negative pole of the first diode (D1-C) positive pole and the second diode (D2-C), be connected with drop-down the 7th electric capacity (C10-C) between the 12 resistance (R14-C) and the 13 resistance (R15-C), the inverting input of four-operational amplifier (LM064C) is connected with drop-down the 15 resistance (R16-C), the 16 resistance (R17-C) be connected between the inverting input and output terminal of four-operational amplifier (LM064C) after the second adjustable resistance (W12-C) is connected, the adjustment end of the second adjustable resistance (W12-C) is connected with the output terminal of four-operational amplifier (LM064C), the output terminal of four-operational amplifier (LM064C) connects an end of the 17 resistance (R20-C), the other end of the 17 resistance (R20-C) connects drop-down the 8th electric capacity (C9-B), and as the output terminal of high precision amplitude conversion and Circuit tuning,

The output terminal of described integral compensation and Circuit tuning (A) is connected with the input end of described high precision amplitude conversion and Circuit tuning (B).

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