CN101762447A - Detection circuit of contamination level of oil liquid - Google Patents
Detection circuit of contamination level of oil liquid Download PDFInfo
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- CN101762447A CN101762447A CN200810188324A CN200810188324A CN101762447A CN 101762447 A CN101762447 A CN 101762447A CN 200810188324 A CN200810188324 A CN 200810188324A CN 200810188324 A CN200810188324 A CN 200810188324A CN 101762447 A CN101762447 A CN 101762447A
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Abstract
The invention relates to a detection circuit of the contamination level of oil liquid by counting particles in various kinds of oil liquid. The detection circuit is based on a photoelectric principle and enables oil liquid to be detected to pass through a gap between transparent thin plates; and the light of a light-emitting diode passes through a convex lens and is turned into parallel beams which are illuminated on the receiving head of a receiving diode by the oil-dipped transparent thin plates so that a current signal can be generated at both ends of the receiving diode. The signal level is in direct proportion to the sizes of the particles so as to confirm the number of particles contained in the oil liquid according to the number of pulses and confirm the sizes of the particles according to the signal level. After I-V conversion and amplification, the current signal is turned into a processible voltage signal which is divided into a direct current signal and an alternating current signal to be directly sent to the signal input end and the threshold-setting end of a particle-counting comparator; and the amplitudes of the output pulses of the comparator are limited by an amplitude-limiting diode and sent to a counting circuit for counting the number of the particles in various grain diameters. The invention has high measuring height, high stability and convenient use.
Description
Technical field
The design's invention belongs to a kind of testing circuit, relates generally to the photoelectric switching circuit of grain count in the various fluid, and signal is impulse output circuit and counting output circuit relatively.
Background technology
Fluid is the actuating medium of hydraulic system, and the control information of hydraulic system and the transmission of operation power all will be finished by fluid, and be all closely related with the performance of hydraulic oil as the working condition and the serviceable life of elements such as hydraulic pump, oil motor, various valves.In recent years, for monitoring fluid is to guarantee the hydraulic system trouble free service in real time, a lot of research departments are to cause this factor of transmitted light decay to design multiple method of testing to pollutant solid particle in the fluid according to the solid particle in the fluid.Present test circuit adopts earlier more detection signal is amplified, and data is handled according to the corresponding tables of international pollution degree of hydraulic oil grade code and granule density by software processes test monitoring signal then, shows the grade of hydraulic oil.But most circuit all has long, shortcoming such as accuracy is low, conversion accuracy is low switching time.We adopt high precision light activated element HRLD-400 in circuit design, and obtain stablizing real result through a series of data processing such as the amplification of signal, comparison, countings.Circuit of the present invention is directly to detection signal classification processing according to hardware design.Simplify the processing of software, improve testing precision.
Summary of the invention
The purpose of this invention is to provide a kind of contamination level of oil liquid and detect photoelectric switching circuit, it is simple to make it have light path design, characteristics such as wide, the simple to operate and measuring accuracy height of measurement range.
The present invention measures different-grain diameter particle number contained in the fluid with photoelectricity transformation principle, calculates the dustiness of fluid according to this.Its principle is as follows:
After the light beam process convex lens refraction that semiconductor laser diode sends, become parallel beam, directional light is the optical glass window of A by sectional area, shine on the photoelectric receiving tube, when not having particle in the tested fluid, circuit output be a fixed voltage E, in fluid, have projected area be the particle of a by the test light hole, stopped parallel beam, make the transmitted light decay, this moment, output amplitude was E
0Pulse, E
0=(a/A) E;
If particle is spherical, or can equivalence be the sphere of d, then for diameter
E
0＝(πd
2E)/(4A)
The projected area and the pulse voltage amplitude that are particle are linear.Can judge the size of particle thus according to pulse height.
Detection circuit of contamination level of oil liquid divides four modular circuits, and they are respectively: photoelectric switching circuit, conversion of signals amplifying circuit, signal be impulse output circuit and counting circuit relatively.Its block diagram as shown in Figure 1.Design concept as shown in Figure 2.
Photoelectric switching circuit comprises the pipe of giving out light, convex lens, test oil passage and receiving tube.Photoelectric switching circuit is mainly used in that the particle information in the fluid is converted to can observed electric signal, for the processing of subsequent conditioning circuit.
The major function of conversion of signals amplifying circuit is the faint current signal that opto-electronic conversion is come out to be become voltage signal and this signal is amplified, the circuit diagram of photoelectric switching circuit and conversion of signals amplifying circuit as shown in Figure 3, as can be seen from Figure 3: the light signal that sends when light emitting diode, become parallel beam after the planoconvex lens refraction, shine on the photosensitive again fulgurite T2 after passing the test oil passage, photoelectric tube T2 conducting, flow through the current signal of T2 through the I-V of operational amplifier A 1 conversion becoming voltage signal, pass through amplification again by A2, final level conversion through T3 becomes processed signal.In the circuit, C1 is mainly used in elimination and differs as miller compensation electric capacity, prevents vibration.
Signal comparison impulse output circuit is used for the voltage signal that contains particle information of amplifying circuit output is divided into two-way, one road direct current signal, one tunnel AC signal, the threshold value that direct current signal is delivered to voltage comparator by the adjustable potential meter is provided with end, AC signal is delivered to the signal input part of voltage comparator, for the particle of particle diameter less (5～50 μ m) when relatively exporting since signal a little less than, need add one-level again and amplify and isolate.AC signal will add the transmission mushing error that an amplitude limiter circuit reduces signal when being input to comparer.The circuit diagram of signal comparison impulse output circuit as shown in Figure 4.
Counting circuit is used for to the counting of each particle diameter granule number pulse, and when impulse output circuit had pulse output, counting circuit was just counted this pulse, and count results shows by display module or directly handled by single-chip microcomputer.
Description of drawings
The circuit diagram of signal processing circuit (only illustrates with three passages) as shown in Figure 4:
In treatment circuit, treatment circuit is divided into two-way, each own different effect. Following a road as threshold adjustment circuit, and the direct current signal according to input carries out certain conversion process, exports six tunnel DC levels (only drawing three tunnel), as the comparative voltage of the operational amplifier in six channels of whole circuit output. A road of top is the major part of whole circuit, is input as AC signal. Behind the amplitude limit and isolation through operational amplifier A 3, the signal of telecommunication is delivered in the passage of six outputs, each passage has different threshold voltages, and this threshold voltage is obtained by the variable resistance dividing potential drop by following DC channel. After relatively, the output pulse square wave is to counter corresponding to each passage, output detections result. In Fig. 3, U1 is the AC signal isolated amplifier of the signal of sensor output, U2 is the direct current signal isolated amplifier of the signal of sensor output, and U4 is the amplitude limit unit of AC signal, and U5, U6, U7 are comparator circuit (being 3 in 6 passages). The setting value of its threshold value is by the dividing potential drop gained of DC level on slide rheostat of lower part, and threshold value can be by setting the adjustment of slide rheostat resistance. In theory, particle is more big, and signal voltage is also more big, and when particle was wandered about as a refugee windowing along with fluid, signal just disappeared. So the number according to pulse can be determined quantity particles contained in the oil, can determine the size of particle according to the level of pulse.
Purpose of the present invention can adopt following technical scheme to realize: it comprises photosignal change-over circuit and signal of telecommunication classification treatment circuit two parts (only with a group pipe being described).
Described optical-electrical converter is light-sensitive element, can be complementary with LASER Light Source well by the size of adjusting the time of integration, and it is operated in the range of linearity, improves the accuracy of measurement of system.
Accompanying drawing 1 is schematic diagram of the present invention.
As can be seen from Figure 1: the present invention includes four main component units, they are relatively impulse output circuit sum counter circuit of photoelectric switching circuit, amplifying circuit, signal.
Accompanying drawing 2 is design concept schematic diagrames of the present invention. The general frame of finding out this circuit that can be clear and definite from this figure and the flow direction of signal.
Accompanying drawing 3 is photoelectric conversion module schematic diagrames of the present invention.
Among the figure: from a left side to oil, be followed successively by semiconductor luminotron, convex lens, oil pipe road, particle, light glass window, measuring probe.
Accompanying drawing 4 is photoelectric switching circuits of the present invention.
Among the figure: from a left side to oil, be followed successively by semiconductor luminotron, convex lens, oil pipe road, particle, light glass window, measuring probe, I-V switching device, the voltage signal amplifying device. Wherein, A1, A2 are operational amplifier OP27, and the function of amplifier A1 is that the current signal that photoelectric tube produces is converted to voltage signal, and the function of amplifier A2 is that the faint voltage signal that A1 changes is amplified, so that the processing of subsequent conditioning circuit. T1 is semiconductor laser diode, and T2 is light receiving tube. The T1 positive pole joins the direct ground connection of negative pole by resistance R 3 and+14V dc source. Light receiving tube triode T2 colelctor electrode links to each other with the input 2 of operational amplifier A 1, and emitter stage links to each other with the input 3 of operational amplifier A 1. Resistance R 1 two ends link to each other with output 6 with the input 2 of operational amplifier A 1 respectively, and resistance R 4 is connected the output 6 of operational amplifier A 1 and the input 3 of operational amplifier A 2. Resistance R 2 one ends link to each other publicly with circuit, one end links to each other with the input 2 of operational amplifier A 2, link to each other with output 6 with the input 2 of operational amplifier A 2 respectively after capacitor C 1 and the potentiometer R5 parallel connection, the output 6 of resistance R 6 concatenation operation amplifier A2 and the base stage of triode T3, the colelctor electrode of triode T3 connects+dc source of 14V, launch very being input in the passage of signal. The optical signal that sends when light emitting diode, become collimated light beam after the planoconvex lens refraction, shine again on the photo resistance T2 after passing the test oil passage, photoelectric tube T2 conducting, flowing through, conversion becomes voltage signal through the I-V of operational amplifier A 1 for the current signal of T2, pass through again the amplification by A2, finally pass through the level conversion of T3, become processed signal. In the I-V change-over circuit, because parasitic capacitance lags behind phase place, circuit also becomes and vibrates easily, and in 2 ends and capacitor C 1 of 6 terminations of amplifier A2, Main Function is to eliminate to differ, and prevents vibration.
Accompanying drawing 5 is signals collecting of the present invention and amplifying circuit.
Among the figure: A3 is the amplification and the channel isolation of AC signal, and A4 is the amplification sampling passage of direct current signal, adds a capacitor C 12 and diode D9 in order to eliminate introducing, amplitude limit and the filtering clutter that the circuit transmission is disturbed at 3 ends of amplifier A3.AC signal by A3 is through the threshold value comparer of the back of flowing through after amplifying, and the threshold value setting of comparer is obtained through the slide rheostat dividing potential drop by the output signal of A4 amplifier.The threshold value that each size particles is corresponding different, the intervention resistance of the slide rheostat by each road is set just can very easily voltage threshold be set to the corresponding representative value of each particle diameter on.A6 and A10 are the secondary circuit of the upper limit of AC signal output, in order to prevent the amplification to undesired signal, establish the measuring accuracy that this amplitude limiter circuit can be improved circuit, reduce error.A5 be the small particle diameter AC signal two-stage amplifier, since the small particle diameter AC signal fainter, in the transmission course of signal, have disturbance again, these two kinds of signals are difficult to distinguish, so add one-level amplifies at the A5 place, extraction for the small particle diameter signal is helpful, thereby improved measuring accuracy, added a limiter A10 again at the output terminal of A5, it is just more accurate to measure.A7, A8, A9, A11, A12 and A13 are six road comparator circuits.The setting value of its threshold value is by the dividing potential drop gained of DC level on slide rheostat of lower part, and threshold value can be by setting the adjustment of slide rheostat resistance.The signal output of six road comparers can connect diode and come the pulse signal of output is carried out amplitude limit.The counting source of counting circuit just is connected on the rear end of limiter diode.
Counting circuit carries out programmed process with single-chip microcomputer, and hardware circuit is exactly the input end that the rear end of six road limiter diodes is connect the step-by-step counting of single-chip microcomputer respectively.
Embodiment
In conjunction with the accompanying drawings, specify specific embodiments of the invention.
As accompanying drawing 4 and shown in Figure 5: the present invention includes relatively impulse output circuit sum counter circuit of photoelectric switching circuit, I-V change-over circuit, signal.Be provided with measuring sonde in the photoelectric switching circuit inside shown in Fig. 4, the measuring sonde two side is provided with optical glass window.One group of lens is set between measuring sonde and semiconductor laser, and the measuring sonde right side wall is provided with the corresponding side of optical glass window and is provided with photoelectric commutator.The photoelectric commutator of present embodiment adopts light activated element HRLD-400, and light activated element is connected with signal comparison impulse output circuit with emitter-follower by I-V change-over circuit A1, signal amplification circuit A2.
As shown in Figure 5: the signal of emitter-follower output is divided into two-way by AC signal passage A3 and direct current signal passage A4, AC signal is input to the input end of six road comparers, the threshold value of receiving six road comparers after direct current signal is pressed by the adjustable potential score is provided with end, by the dividing potential drop of regulating the adjustable potential meter six passage threshold values is set.Receive counting circuit by producing six road pulse signals behind six road comparator circuits behind the limiter diode amplitude limit, counting circuit is used for counting the pulse number of each passage output.
Claims (6)
1. a detection circuit of contamination level of oil liquid relatively reaches impulse output circuit comprising photoelectric switching circuit, signal amplification circuit, signal.It is characterized in that: in photoelectric switching circuit, be provided with measuring sonde HRLD-400, put convex lens, one group of lens is set between measuring sonde and light emitting diode in the light emitting diode rear end.
2. detection circuit of contamination level of oil liquid according to claim 1 is characterized in that: measuring sonde one distolateral wall is provided with optical glass window.
3. detection circuit of contamination level of oil liquid according to claim 1 is characterized in that: measuring sonde used in the photoelectric switching circuit is HRLD-400.
4. detection circuit of contamination level of oil liquid according to claim 1 is characterized in that: through I-V conversion and the signal after amplifying be divided into direct current and exchange two paths and handle.
5. detection circuit of contamination level of oil liquid according to claim 1 is characterized in that: at AC signal input amplifier one end the secondary circuit of the upper limit is arranged.
6. detection circuit of contamination level of oil liquid according to claim 1 is characterized in that: the threshold voltage that end is set in comparator threshold is that the dividing potential drop of DC component on the adjustable potential meter by amplified signal obtains, and can remove common mode interference.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810188324A CN101762447A (en) | 2008-12-25 | 2008-12-25 | Detection circuit of contamination level of oil liquid |
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|---|---|---|---|
| CN200810188324A CN101762447A (en) | 2008-12-25 | 2008-12-25 | Detection circuit of contamination level of oil liquid |
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| CN101762447A true CN101762447A (en) | 2010-06-30 |
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| CN200810188324A Pending CN101762447A (en) | 2008-12-25 | 2008-12-25 | Detection circuit of contamination level of oil liquid |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104067106A (en) * | 2014-06-30 | 2014-09-24 | 深圳华盛昌机械实业有限公司 | Particulate matter (PM) 2.5 concentration detection device and detection method, and air quality detector |
| WO2019109874A1 (en) * | 2017-12-05 | 2019-06-13 | 西人马联合测控（泉州）科技有限公司 | Detection method for concentration of fluid particulate matter |
-
2008
- 2008-12-25 CN CN200810188324A patent/CN101762447A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104067106A (en) * | 2014-06-30 | 2014-09-24 | 深圳华盛昌机械实业有限公司 | Particulate matter (PM) 2.5 concentration detection device and detection method, and air quality detector |
| CN104067106B (en) * | 2014-06-30 | 2016-05-18 | 深圳华盛昌机械实业有限公司 | A kind of PM2.5 concentration detection apparatus, detection method and air quality detector |
| WO2019109874A1 (en) * | 2017-12-05 | 2019-06-13 | 西人马联合测控（泉州）科技有限公司 | Detection method for concentration of fluid particulate matter |
| US11092534B2 (en) | 2017-12-05 | 2021-08-17 | Fatri United Testing & Control (Quanzhou) Technologies Co., Ltd. | Method for detecting concentration of particles in fluid |
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Application publication date: 20100630 |