CN1005287B - Pulse thermometer and humidometer - Google Patents
Pulse thermometer and humidometer Download PDFInfo
- Publication number
- CN1005287B CN1005287B CN85100871.2A CN85100871A CN1005287B CN 1005287 B CN1005287 B CN 1005287B CN 85100871 A CN85100871 A CN 85100871A CN 1005287 B CN1005287 B CN 1005287B
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- China
- Prior art keywords
- temperature
- pulse
- humidity
- value
- sensitive element
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Abstract
In the present invention, a linear conductance sensing element network is connected to a multi-resonance vibrator loop, so that the number of output pulses per unit time is just proportional to the amount of measured physical parameters. A reversible preset counter is used for displaying the same digital value and sign as those of a traditional representation. If the sensing element is a thermal-dependent resistor, the meter can be used as a thermometer; if the sensing element is a humidity-dependent resistor, the meter can be used as a humidometer; if other sensing elements are used, the meter can be used as a displaying meter for other physical measurements. In addition, the meter is provided with a voltage stabilizing system with low voltage and low power consumption so as to obtain high stability.
Description
Pulse temperature hygrometer is a kind of cold store that is applicable to, the electronic device of the temperature and humidity measurement of material storage and transportation and air conditioning room.
Existing this class surveying instrument mainly contains two classes on method for digitizing:
1. simulation is promptly adopted sensitive element with temperature, and humidity converts DC voltage to, adopts digital voltmeter (analog to digital conversion) to provide the digital value of measurement again.The disadvantage of this method is to be subject to the interference of external electromagnetic field and to be difficult to transmit in the long distance.
2. frequency method in view of the existing shortcoming of simulation, converts temperature, humidity to mode that frequency is measured, Recent study many.U.S. Pat-446 4067, IPC, G01K7/24, (open August 7 1984 date) is a kind of pulse temperature meter the most approaching with the present patent application technical characterictic, it is to adopt the RC oscillatory circuit that contains non-linearization sensing element (employing segment approaching method) that the data that collect are become pulsed frequency, pass through the variable frequency frequency dividing circuit again, counter, initial value adjusting gear and frequency division ratio are adjusted the retroactive effect of circuit, and by in the read only memory (ROM) in advance the storage calculation procedure and data handle, obtain shown measurement numerical value at last.
But up to now, comprise the United States Patent (USP) of above-mentioned documents, all there are several common shortcomings in the frequency measurement method that all have been realized:
1. direct corresponding relation can not be obtained between pulsed frequency value of being exported and the measurand, and an irregular data table of comparisons can only be obtained.Want directly to read and measure just necessary Computing and the data processing of adopting of numerical value, in addition can only adopt the method for tabling look-up just can obtain measured value.Therefore, the former technical sophistication, the latter uses extremely inconvenient.
2. positive temperature can only be measured and negative temperature can't be measured.Because the pulse frequency can be exported bigger numerical value when dut temperature raises, the less numerical value of exportable pulsed frequency when temperature reduces.But for negative temperature, when dut temperature reduced, when dropping to-50 ℃ by-20 ℃, oscillator was along with the reduction of dut temperature, can only export the littler pulse number of ratio-20 ℃ numeral, and in fact be to need to obtain and-50 ℃ of corresponding bigger numerical (absolute value).So the employing frequency method, the measurement of negative temperature never fundamentally is resolved.
3. can't measure humidity.
The objective of the invention is to design a kind of new type measuring instrument device of measuring humiture, overcoming these above-mentioned shortcomings, thereby satisfy fresh-keeping, various cold stores, the needs of the remote temperature sensing remote control in places such as material storage and transportation and air conditioning room.
The present invention adopts circuit cheaply, by sensitive element electrical leadization and calculating Calibration Method, rationally matches the parameter value of relevant elements in the loop, makes oscillator output umber of pulse directly become corresponding relation in the unit interval with tested humiture.
Fig. 1 is electrical lead sensor network and electrical lead curve for sensor, according to the requirement of measuring accuracy, can be divided into plurality of sections at whole measurement zone, but every section will have 3 electric conductivity value linear, leads linear to guarantee whole electricity.
Sensor is thermistor or hygristor, and Fig. 2 is a multivibrator, requires to have high input impedance, stable supply voltage.Sensor places oscillation circuit, is equipped with series connection, parallel resistance and oscillating capacitor, and it is suitable that its parameter will be matched, and makes oscillation frequency just suitable with the numerical value of the physical quantity of measured parameter.Fig. 3 is the block scheme of counting display circuit, and wherein square frame 2 is a gating circuit, is in principle to constitute with " with door " or non-conjunction, add a second signal on one side, add the frequency signal that oscillator is sent on one side, control gate is output as frequency values, and frequency can be represented measurand.Square frame 4 is surveyed and is used subtraction below 0 ℃ for can preset up-down counter.Use addition more than 0 ℃, make the numerical value that obtains consistent with people's custom.
Now some of them major technology problem is described below:
(1) sensitive element electrical leadization
If the scope of measurand (temperature, humidity) is X1 to X3, an intermediate value X2 is got in the centre.At this 3 point, sensitive element (thermistor, hygristor) resistance is respectively R1, R2, R3.The present selects a fixed resistance Rs to connect with this sensitive element to form sensor network, makes this network at the electric conductivity value (δ 1, δ 2, δ 3) of this 3 point (X1, X2, X3) point-blank.
Be δ 1+ δ 3=2 δ 2
This moment, the resistance of resistance in series Rs should be
Rs＝（R1R2+R2R3-2R1R3）/（R1+R3-2R2）
The linearity and expansion measurement range in order to improve network then can be divided into plurality of sections with the specified measurement scope.Every section with a sensitive element and a resistance in series, make it on each measurement point electric conductivity value point-blank, as shown in Figure 1.Fig. 1 (a) is the electrical lead sensor network.RX1, RX2 ... RXn is the resistance value of the used sensitive element of each measurement zone.RS1, RS2 ... RSn is its series impedance.I, II among Fig. 1 (b) ... each section is the curve of electrical leadization.Electric conductivity value on each measurement point point-blank.
(2) calculate the pulse signal generating circuit of calibrating.
The sensitive element of electrical leadization is placed a multivibrator circuit, and is equipped with parallel resistance Rp(electric conductivity value δ p), as shown in Figure 2, γ X is the electric conductivity value of sensor network among the figure, the relation of unit interval output umber of pulse f and network parameter is:
f＝（δp+γx）/2cln（1+2Rb/Ra）
If make 21n(1+2Rb/Ra)=1
F=(δ p+ γ x then)/c
If during X=X1, Yx=Y1; During X=X2, Yx=Y2;
Then obtain f1=(δ p+ γ 1)/c
f2＝（δp+γ2）/c
Separate c=(γ 2-γ 1)/(f2-f1)
δp＝cf2-γ2
(3) can preset the up-down counter circuit.
Fig. 3 is the block scheme of counting display circuit.1 is the sensitive element probe among the figure, and it exports pulse.Square frame 2 is a gating circuit; Square frame 3 is a timing circuit; Square frame 4 is for can preset up-down counter, and its a end is for presetting the number end.B is a signal input part, and the train of impulses in the unit interval is added to counter.C is plus-minus bus control end.Beginning, counter is carried out subtraction, successively decreases successively from preset number.When reducing to zero, detect by zero-crossing detector (square frame 5), via controller 7 makes counter become the addition state by the subtraction state.Presetting number when for example temperature is 0 ℃ is 1000, and subzero 30 ℃ umber of pulse is decided to be 700.Subtracting each other the back residual value is 300,, demonstrates-30.0 ℃ by decoder driver circuit.Positive 30 ℃ umber of pulse is 1300, after presetting number and subtracting 1000, is detected by zero-crossing detector, and by controller, counter becomes addition by subtraction, and residual value is 300, adds "+" before the numeral, get final product+30.0 ℃ digital indicated value.Discr. is in order to differentiate initial zero or zero passage, to reduce maloperation.
(4) the little electric current mu balanced circuit of low-voltage.
Be provided with the voltage dependent resistor (VDR) mu balanced circuit in order to guarantee the stability of under the little electric current of low-voltage, working, as shown in Figure 4.Rv is a voltage dependent resistor (VDR) among the figure, and R1 is for regulating resistance, and R2 is the resistance that is in series with voltage dependent resistor (VDR), so that voltage dependent resistor (VDR) is operated in the sensitive volume.T is a transistor, and R3 is a biasing resistor, and its principle of work is when input voltage Vi raises, electric current on the RV increases, thereby the forward bias of transistor T is strengthened, and its conductance current is increased, the pressure drop of regulating resistance R 1 is increased, thereby V0 is reduced to guarantee the stability of output voltage.
The present invention has following advantage: the anti-electromagnetic interference (EMI) of (1) this instrument energy; (2) can long-distance transmissions, help realizing remote measuring and controlling; (3) flexible and changeable, range accuracy is all adjustable, can adapt to many-sided needs; (4) stable performance is with low cost, is easy to promote.
Description of drawings:
Fig. 1 (a) is the electrical lead sensor network;
Fig. 1 (b) is the electrical lead curve;
Fig. 2 is the multivibrator that has the electrical lead sensitive element;
Fig. 3 is the block scheme of counting display circuit, and square frame 1 is the sensitive element probe among the figure; Square frame 2 is a gating circuit; Square frame 3 is a timing circuit; Square frame 4 is for can preset up-down counter, and wherein a is for presetting the number end; B is a signal input part; C is plus-minus bus control end.Square frame 5 is a zero-crossing detector; Square frame 6 is a Discr.; Square frame 7 is a controller; Square frame 8 is a decoder driver; Square frame 9 is a display.
Fig. 4 is the voltage dependent resistor (VDR) mu balanced circuit.
Embodiment: adopt the present invention to produce the model machine that can measure temperature and humidity, practice has proved feasibility of the present invention.
Claims (14)
1, a kind of Pulse temperature hygrometer that is used to measure temperature and humidity, it comprises: sensor (being the sensor network of electrical leadization), multivibrator, timer, controller, counter, decoder driver, display is characterized in that:
Sensor is the sensitive element that adopts the electrical leadization of directly calibrating on three points;
Comprised the electrical lead sensitive element of directly calibrating on three points in the multivibrator circuit, electricity is led δ p and resonant capacitor c, becomes direct corresponding relation between the pulsed frequency that this oscillator is exported and dut temperature (or humidity) value;
Counter is to adopt to preset up-down counter, the numerical value when presetting number and should be the null value physical quantity, the output pulse frequency of default value and multivibrator mutually difference just expression measure temperature (or humidity) and be worth;
Be provided with zero-crossing detector, in the time can presetting the presetting number difference is zero mutually with the output pulse frequency of multivibrator of up-down counter, zero-crossing detector makes by Discr., controller can preset the computing that up-down counter realization subtraction becomes addition, realizes the demonstration of negative temperature and positive temperature simultaneously by decoder driver circuit;
Be provided with the loss when guaranteeing the instrument operate as normal and reducing signal to carry at a distance of low-voltage, little electric current voltage stabilizer.
2, Pulse temperature hygrometer according to claim 1, it is characterized in that the electrical lead sensitive element on three points, directly calibrated, should satisfy with the resistance in series Rs value that resistance R1, R2, R3 constituted of X1, X2,3 corresponding sensitive elements of X3 (thermistor, hygristor) in measurand (temperature, the humidity) scope:
Rs＝（R
1R
2+R
2R
3-2R
1R
3）÷（R
1+R
3-2R
2）
And on X1, X2, three points of X3, carry out the electrical lead processing; When adopting n sensitive element, then calibration on 3n point.
3, Pulse temperature hygrometer according to claim 1 is characterized in that the shunt conductance δ p in the multivibrator circuit should satisfy:
δp＝f
2c-r
2
Resonant capacitor C should satisfy:
C＝（r
2-r
1）/（f
2-f
1）
4, Pulse temperature hygrometer according to claim 1 is characterized in that: the little electric current voltage stabilizer of low-voltage is to have adopted by voltage dependent resistor (VDR) Rv, regulates resistance R
1, resistance in series R
2, transistor T, biasing resistor R
3Form.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN85100871.2A CN1005287B (en) | 1985-04-01 | 1985-04-01 | Pulse thermometer and humidometer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN85100871.2A CN1005287B (en) | 1985-04-01 | 1985-04-01 | Pulse thermometer and humidometer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN85100871A CN85100871A (en) | 1986-08-13 |
| CN1005287B true CN1005287B (en) | 1989-09-27 |
Family
ID=4791490
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN85100871.2A Expired CN1005287B (en) | 1985-04-01 | 1985-04-01 | Pulse thermometer and humidometer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1005287B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101398334B (en) * | 2007-09-29 | 2010-12-08 | 联兴微系统科技股份有限公司 | Temperature-sensing element correcting method and correcting system |
| DE102010038361A1 (en) * | 2010-07-23 | 2012-01-26 | Robert Bosch Gmbh | Method for measuring temperature of ammonia contained in reducing agent tank of selective catalytic reduction catalyst system for motor car, involves forming predictor from conductance, and evaluating predictor for concluding temperature |
-
1985
- 1985-04-01 CN CN85100871.2A patent/CN1005287B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CN85100871A (en) | 1986-08-13 |
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| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CI01 | Publication of corrected invention patent application |
Correct: Pulse thermometer False: Pulse temperature and humidity agent Number: 13 Page: 41 Volume: 2 |
|
| C13 | Decision | ||
| GR02 | Examined patent application | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| ERR | Gazette correction |
Free format text: CORRECT FROM: PULSE TEMPERATURE AND HUMIDITY AGENT TO: PULSE TEMPERATURE HYGROMETER |
|
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |