CN2594792Y - Capacitor-type moisture sensor for meteorological detection - Google Patents
Capacitor-type moisture sensor for meteorological detection Download PDFInfo
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- CN2594792Y CN2594792Y CN 03228208 CN03228208U CN2594792Y CN 2594792 Y CN2594792 Y CN 2594792Y CN 03228208 CN03228208 CN 03228208 CN 03228208 U CN03228208 U CN 03228208U CN 2594792 Y CN2594792 Y CN 2594792Y
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Abstract
The utility model relates to a capacitor-type moisture sensor for high-altitude meteorological detection. A moisture sensing element or a compensation capacitor is connected between a first Darlington circuit and a second Darlington circuit by a converting switch, and an RC filter is connected with an output terminal of a circuit. When the utility model is adopted, the capacitor-type moisture sensor is utilized to replace a resistance-type moisture sensor which is used for a digital sonde at present; so the moisture detecting performance of the digital sonde can be improved further; in addition, the utility model can be used for detecting the moisture under the condition of high-altitude severe environment of 45-90 DEG, the detection range can reach to 0-100% RH, the measuring accuracy is smaller than 5%RH, and the hysteresis coefficient is smaller than 1 seconds; thus, the utility model has the advantages of big measuring range, high measuring precision and high sensitivity; so the utility model can be used for the moisture measurement of the high-altitude meteorological detection and can also be used for automatic weather stations of the ground. If the utility model is developed secondarily, the utility model can be applied to the fields of the national economy such as the moisture automatic control systems of paper making, warehouses, libraries, textile, tobacco, etc.
Description
Technical field
The utility model relates to the humidity sensor in the humidity automatic control system, particularly a kind of aerological sounding capacitance type humidity sensor.
Background technology
The humidity sensor kind that is used for aerological sounding in the prior art is a lot, mechanical as hair, roll send out, detection that casing etc. is applicable to the meteorological humidity of mechanical code formula sonde and ground because its degree of accuracy and adaptability are relatively poor, now eliminated gradually.Electron type now commonly used resistance-type and condenser type arranged, they generally add that by the humidity inductive element metering circuit is formed.The advantage of resistance-type humidity sensor is the Measurement Resolution height, and its metering circuit is simple; And the great advantage of capacitance type humidity sensor to be its low humidity hygrometric performance be better than resistance-type greatly, good stability is fit to aerological sounding.
But, be disposable use instrument as the sonde of sonde device, require cost low, but its environmental requirement is very high again, temperature range is+50～-90 ℃, therefore, adopt capacitance type humidity sensor at first will solve following two big difficult points:
Sonde in use the humidity inductive element be to be exposed to extra-organismally, the lead of introducing body is very long, so, the distributed capacitance that lead produces and the distributed capacitance of circuit itself will influence the measuring accuracy and the stability of humidity sensor.
2. the serviceability temperature scope of humidity inductive element is-40 ℃～+ 50 ℃ in the market, and being lower than-40 ℃ of measurement performances will reduce greatly, will reach-90 ℃ and sonde serviceability temperature scope is minimum.If require the humidity inductive element to reach-90 ℃ of requirements actually, then its manufacture craft will be very complicated, and cost improves greatly, is worthless.
Abroad, some manufacturers adopt some measures to attempt to solve these difficult points, are adopted as the method that the humidity inductive element is heated as Finland Vaisala company, and finish the conversion of capacitance-voltage with multiple-harmonic oscillator and low-pass filter circuit.But their way complex process, the cost height.
Other manufacturers improve on metering circuit, as the patent of the German Fraunhofer company (patent No.: US5 of " measuring the circuit and the method that influence capacity cell capacitance-voltage performance parameter ", 235,267), its measure is to apply the one-period voltage signal to capacity cell, go out the zone of capacitance-voltage characteristics curve by the integrated detected of capacity cell electric current and voltage signal partial periodicity, from this zone, measure the value of consult volume of surveying according to parameter and capacitance relation again, though this patented technology can improve measuring accuracy and eliminate some interference, but still can not solve above-mentioned two difficult problems.
Summary of the invention
Technical problem to be solved in the utility model is to overcome existing defective in the above-mentioned prior art, for aerological sounding provides a kind of temperature compensation that both had, can eliminate distributed capacitance again, and the capacitance type humidity sensor that technology is simple, cost is low.
The utility model has adopted following technical proposal to solve its technical matters: a kind of aerological sounding capacitance type humidity sensor, it is characterized in that: by being connected a humidity inductive element Cs or a building-out capacitor C1 by switch K between resistance R 2, R3 and transistor Q1, Q2 first Darlington circuit of forming and second Darlington circuit of being made up of resistance R 4, R5 and transistor Q3, Q4, the wave filter of being made up of resistance R 6, capacitor C 2 is connected circuit output end.
The utility model replaces the resistance-type humidity sensor that uses at present on digital sonde with capacitance type humidity sensor, and the humidity detection performance of this sonde is further improved, can under the high-altitude rugged surroundings of environment temperature 45～-90 ℃, survey humidity, its scope can reach 0～100%RH, measuring accuracy≤5%RH, lag coefficient≤1 second, therefore the utility model measurement range is big, measuring accuracy is high, highly sensitive, can be used for the measurement of humidity in the aerological sounding, also can be used for the ground automatic weather station.As to it carry out secondary development and also can be applied in the national economy every field, as the humidity automatic control system of industries such as papermaking, warehouse, library, weaving, tobacco.
Description of drawings
Accompanying drawing is an electrical schematic diagram of the present utility model.
Embodiment
Come the utility model is further described below in conjunction with accompanying drawing and embodiment.
With reference to accompanying drawing, first Darlington circuit that the utility model is made of resistance R 2, R3 and transistor Q1, Q2, between voltage signal source and humidity inductive element, add this darlington amplifying circuit, in order to eliminate the integrating effect that distributed capacitance produced that long lead causes, improve edge, voltage signal front and back.
Second Darlington circuit is made of resistance R 4, R5 and transistor Q3, Q4, between first Darlington circuit and second Darlington circuit, be connected a humidity inductive element Cs by switch K, can adopt differential method to measure the size of its electric capacity, and utilize second darlington amplifying circuit to produce positive pulse.In addition, other and meet a building-out capacitor C1 at this humidity inductive element Cs, and change with switch K, except that the temperature coefficient of eliminating metering circuit itself, also can cooperate the sonde main circuit board, use for reference atmospheric temperature that temperature sensor is surveyed in the sonde, the temperature coefficient of humidity inductive element Cs is revised, to guarantee sensor operating accuracy at low temperatures.
The wave filter of being made up of resistance R 6, capacitor C 2 is connected circuit output end, can convert positive pulse to DC voltage, and the size of measuring condenser type humidity inductive element by the DC voltage height indirectly is a humidity value.
Below elaborate principle of work of the present utility model:
Voltage signal source Vs adds first Darlington circuit by repeating resistance R1 with positive pulse signal, and the very steep pulse signal in edge before and after producing after amplifying is by switch K switching humidity inductive element Cs or building-out capacitor C1.
When switch K meets humidity inductive element Cs, output moisture measurement value; When switch K meets building-out capacitor C1, because the temperature performance of building-out capacitor C1 is in advance through measuring, thereby the reference capacitance value when can be used as different atmospheric temperature, carry out the work of treatment (atmospheric temperature is leant out by temperature sensor in the sonde) of relevant temperature compensation by microprocessor in the sonde.Because resistance R 4 is less with the time constant of humidity inductive element Cs (or building-out capacitor C1), when the voltage signal positive transition, Darlington transistor Q3, Q4 continue to keep conducting state (0 voltage), when voltage signal is born saltus step, Darlington transistor Q3, Q4 are by (high voltage), closing time, length depended on the size of humidity inductive element Cs (or building-out capacitor C1), and just the positive pulse width on Darlington Q3, the Q4 collector is directly proportional with humidity inductive element Cs (or building-out capacitor C1).By resistance R 6, capacitor C 2 positive pulse signal is converted to DC voltage, positive pulse is wide more, DC voltage is high more, therefore just can measure the size of humidity inductive element Cs electric capacity indirectly by the height of measuring output end vo, just can measure needed humidity value by suitable calculating again.Because of voltage in the direct current transmission process is not influenced by distributed capacitance, so this humidity value is not influenced by distributed capacitance.
Claims (2)
1, a kind of aerological sounding capacitance type humidity sensor, it is characterized in that: by being connected a humidity inductive element (Cs) or a building-out capacitor (C1) by switch (K) between resistance (R2, R3) and transistor (Q1, Q2) first Darlington circuit of forming and second Darlington circuit of being made up of resistance (R4, R5) and transistor (Q3, Q4), the wave filter of being made up of resistance (R6), electric capacity (C2) is connected circuit output end.
2, aerological sounding capacitance type humidity sensor according to claim 1 is characterized in that: voltage signal source (Vs) adds first Darlington circuit by repeating resistance (R1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03228208 CN2594792Y (en) | 2003-01-16 | 2003-01-16 | Capacitor-type moisture sensor for meteorological detection |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03228208 CN2594792Y (en) | 2003-01-16 | 2003-01-16 | Capacitor-type moisture sensor for meteorological detection |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2594792Y true CN2594792Y (en) | 2003-12-24 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 03228208 Expired - Fee Related CN2594792Y (en) | 2003-01-16 | 2003-01-16 | Capacitor-type moisture sensor for meteorological detection |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2594792Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1973200B (en) * | 2004-06-21 | 2011-03-30 | 意大利电信股份公司 | Physical quantity, particularly humidity detection device, and related detecting method |
-
2003
- 2003-01-16 CN CN 03228208 patent/CN2594792Y/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1973200B (en) * | 2004-06-21 | 2011-03-30 | 意大利电信股份公司 | Physical quantity, particularly humidity detection device, and related detecting method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20031224 Termination date: 20120116 |