CN1162686C - Temperature and humidity measuring and controlling method and circuit - Google Patents
Temperature and humidity measuring and controlling method and circuit Download PDFInfo
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- CN1162686C CN1162686C CNB011261838A CN01126183A CN1162686C CN 1162686 C CN1162686 C CN 1162686C CN B011261838 A CNB011261838 A CN B011261838A CN 01126183 A CN01126183 A CN 01126183A CN 1162686 C CN1162686 C CN 1162686C
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Abstract
The present invention belongs to the technical field of electronics, which particularly relates to a method and a circuit for measuring and controlling temperatures and humidity. The circuit of the present invention is composed of an RC oscillation module, a sampling module, a mapping and display module and a preset and control module, wherein the mapping relationship between a counting value of oscillation impulses and temperatures and between a counting value of the oscillation impulses and humidity are stored in an ROM, and temperature and humidity values can be obtained by meter reading; then the measured temperature and humidity values are compared with a set upper limit value and a set lower limit value, and a control signal is sent out in order that corresponding devices can be started or stopped. The present invention has the advantages of high measurement precision, convenient error correction and easy manufacture of an integrated circuit, and hardware expenses are greatly reduced.
Description
Technical field
The invention belongs to electronic technology field, be specifically related to the method and the circuit thereof of a kind of temperature and humidity measurement and control.
Technical background
The temperature of environment is two different parameters with humidity, but relation of interdependence is arranged again between them, because the saturated vapour pressure of gas descends along with the reduction of temperature.With the refrigeration is example, has condensate water and separate out from air in the air conditioner process of refrigerastion, causes the humidity of environment to change.With humidity sensor sampling environment humidity value, and carry out overall treatment, can obtain temperature, humidity control signal at last and environment temperature and humidity be controlled realizing in conjunction with the temperature sampling value.Present most of air conditioner is only measured and is controlled environment temperature, but human body for environment requirement except temperature, humidity also is an important parameters.Different areas, because the difference of climate situation, the variation of humidity is also very big, and different people is also different to the requirement of ambient humidity, external in recent years advanced air conditioner has begun to consider to add the monitoring of humidity.But, do not enter the reliable and stable practical stage as yet, technically exist bigger difficulty.But people expect to have the stable technology to temperature, humidity side amount and control of dependable performance and emerge, to satisfy actual needs.
Summary of the invention
The objective of the invention is to propose a kind of method stable and reliable for performance and circuit thereof to temperature, the equal energy measurement of humidity and control.
The measurement of humiture and control ultimate principle are as follows: use thermistor and hygristor respectively as the sensor of detected temperatures and humidity, their resistance value changes with the variation of temperature or humidity.For example, in the detected temperatures scope of regulation (as-20 ℃～60 ℃), to the sesame Pu electronic production 103AT-2 of institute type temperature sensor, its resistance value changes in 70k Ω～3k Ω scope.For humidity, relative humidity is in 50%RH～90%RH scope, and when environment temperature was 0 ℃, the variation range of the resistance value of the C5-M3 of Shinyei type humidity sensor was 370k Ω～7k Ω.This resistance (sensor) is linked to be the RC oscillation circuit, and oscillation frequency will change with the variation of temperature or humidity so.If the mapping relations of the count value of oscillating impulse and temperature and humidity are left among the ROM,, just can obtain temperature or humidity value through the comparison of tabling look-up.Temperature that records or humidity value are compared with the upper limit value and lower limit value of the humiture of setting, according to heating or the refrigeration set, humidification or the condition of drying are sent control signal, so that start or stop corresponding apparatus work again.In our design, adopt simple and effective pulse counting method, just earlier once counting is made in the vibration of reference resistance, to determine the time span of counting next time; Insert sensor then, record oscillating impulse number in same time span.According to Theoretical Calculation, can reduce the error that the numerical value change of outward element is introduced greatly; In design, as long as increase a few components, increase capacity and the word length of ROM, just can improve measuring accuracy, this just takes a firm foundation for the design family chip.
Corresponding to the observing and controlling principle of said temperature, humidity, the present invention has designed the telemetry circuit of corresponding temperature, humidity.This circuit by RC oscillator module, sample circuit module, humiture mapping and display circuit module, preset with control circuit module and connect to form through circuit.Its circuit block diagram is seen shown in Figure 1, and the physical circuit block diagram is seen shown in Figure 2.Wherein:
1, RC oscillator module, it is connected and composed through circuit by reference oscillation circuit, temperature sensor oscillatory circuit and humidity sensor oscillatory circuit.Here, reference oscillation circuit provides the clock signal of this system; The temperature sampling value obtains from the temperature sensor vibration; The humidity sampled value obtains from the humidity sensor vibration.The present invention utilizes the character of resistance of sensor with temperature, humidity monotone variation, the relaxation oscillator of sensor access based on Schmidt trigger, so just the variation of resistance value is converted into the variation of frequency.The formula of the frequency values f of oscillator is shown below.
Oscillator constant K osc is shown in the formula 2 in the formula:
V in the formula 2
H, V
LBe respectively Schmidt trigger transition high level and low level, V
DDBe supply voltage.
In order to eliminate the influence of electric capacity, the present invention proposes a kind of improved oscillatory circuit.Temperature sensor RC oscillatory circuit as shown in Figure 3, humidity sensor RC oscillatory circuit is as shown in Figure 4.Pipe among the figure is made switch usefulness, and cal/Meas is a control end.When control end (cal/Meas) is high level, only insert resistance R in the RC oscillation circuit
rWhen control end is low level, be R for resistance in the temperature RC oscillation circuit
r+ R
t(see figure 3), in humidity RC oscillation circuit, resistance is R
r+ R
h| R
p+ R
c, see Fig. 4.
2. sampling module, its function are that the frequency values that changes with temperature, humidity that the RC oscillator produces is sampled.The sample circuit module is connected and composed through circuit by finite state machine 1, temperature and humidity sample counter, temperature and humidity Puzzle lock storage, timer conter.The temperature and humidity counter is connected with temperature and humidity sensor oscillation circuit, and timer conter is connected with reference oscillation circuit, and counter and latch are by state machine 1 control.
Among the present invention, time scaling is made in the vibration that does not insert sensor,, measured the oscillating impulse number in the calibration time interval inserting the vibration sampling of sensor.
Circuit according to Fig. 3 and Fig. 4, the present invention no longer is the number of oscillation of calculating at the set time internal oscillator, but the vibration of the oscillation circuit when not inserting sensor and inserting sensor counts, and the former is called the counting of calibration cycle, and the latter is called the counting of measuring period.At calibration cycle, we are full the counter meter of a certain length (for example 12), write down the number of oscillation of benchmark vibration with another counter; In measuring period, make benchmark vibration produce the count pulse of above-mentioned number equally, write down the number of oscillation that inserts the oscillation circuit behind the sensor.This measuring process shows that we are numbers of oscillation of writing down two kinds of different oscillation circuits in identical time interval Δ t.The advantage of this method is: (1) is according to calculating, we obtain calibration cycle and measuring period the number of oscillation in the Δ t time ratio, it and capacitor C have nothing to do, this is with regard to having eliminated capacitance and changing in time and the influence to oscillation frequency that brings, just eliminated influence, made measurement result more accurate the temperature and humidity measurement precision; The time interval of (2) twice measurement extremely short (be generally second the order of magnitude), both avoided the error introduced because of the instability of measuring system, avoided the error of being introduced because of the numerical value time to time change of outward element again; (3) length of being convenient to adjust counter improves measuring accuracy; (4) helping Temperature Humidity Sensor adopts similar oscillation circuit and computing method to obtain the humiture value.
According to algorithm of the present invention, in time interval Δ t, obtain the sampled value of pulse, so at calibration cycle, benchmark oscillation frequency f
C1Ratio with emending frequency fr is:
M in the formula
1And N is respectively the benchmark vibration and proofreaies and correct the number of oscillation.In measuring period, benchmark oscillation frequency f
C2With survey frequency f
TRatio be:
M
2And n is respectively the benchmark vibration and measures the number of oscillation.Because the time of double sampling is identical, promptly
For temperature survey, have so
For humidity, can get similar results
3. temperature, humidity are shone upon and display module.Mapping and display circuit module are by rom memory, temperature ROM address count number, humidity ROM address counter, comparer, temperature display meter is counted device, the temperature display decoder, the humidity display counter, the humidity display code translator, LCD connects and composes through circuit, comparer is connected with latch with ROM respectively, and with temperature ROM address counter, humidity ROM address counter connects, the temperature display decoder is counted device with temperature display meter successively, temperature ROM address counter connects, the humidity display code translator successively with the humidity display counter, humidity ROM address counter connects.
The sampled value n equality of temperature that sampling module obtains, the relation curve of humidity are monotonically increasing curves.Temperature, humidity mapping must be carried out, just temperature, humidity value can be obtained.Deposited through linearization process among the ROM and temperature, humidity mapping (enum) data after considering to round up, sampled value has been mapped to data among the ROM, just can obtain metric temperature/humidity value.Be that 1 ℃ temperature survey is that example illustrates with precision below: what deposit among the ROM is ... 0.5 ℃, 1.5 ℃ ... n value during equitemperature, this can reach the purpose that rounds up; A decade counter, give the minimum that is changed to temperature measurement range earlier, come a count pulse, make counter add 1, make the ROM address add 1 simultaneously, the value of depositing among n value and the ROM is compared, if the former is greater than the latter, continue counting, otherwise the temperature value that the value of decade counting unit is exactly for we to measure.She Ji advantage is like this: (1) reduces the hardware spending, and promptly used device count is few under the situation that realizes identical function; (2) ROM of available minimum capacity realizes the function that rounds up; (3) can reduce data number of times relatively; (4) ten advance the increase of count value and the increase of address is synchronous, make logic realization simple.
Also need do the temperature correction in the mapping process of humidity, this is because humidity is the function of environment temperature.
Be example with the temperature below, its flow process is described.According to shown in Figure 5, under the control of state machine 1, temperature oscillation carried out sample count, and count value is left in the latch; Under the control of state machine 2, from the ROM of lowest address, obtain the value of depositing then, compare,, compare again, smaller or equal to the former, relatively finish until the latter if the latter greater than the former, continues to increase the address with the value in the latch.This moment, the count value of decade counting unit was exactly a temperature value, can show after decoding.The sample count of humidity and procedure for displaying are also similar.
4. preset and control module.Preset and the control module circuit is connected and composed through circuit by State Control machine 2, temperature maximal value counter, temperature minimum value counter, temperature controller, humidity maximal value counter, humidity minimum value counter, humidity controller, rear end controller.The temperature maximal value is connected with the temperature display decoder with the minimum value counter, and temperature controller is counted device, temperature maximal value and minimum value counter with temperature display meter respectively and is connected; The humidity maximal value is connected with the humidity display code translator with the minimum value counter.The humidity controller is connected with humidity display counter, humidity maximal value and minimum value counter respectively.State machine 2 is connected with temperature, humidity counter, reference oscillation circuit, and is connected with the rear end controller.
Preset temperature wherein and control module can be referring to Fig. 6.From scheming as seen, when preset temperature, under state machine control, show the temperature value of inserting on the one hand, on the other hand the maximum of inserting/minimum temperature value is left in the register respectively.Then the temperature value that measures is compared with the upper and lower limit of setting respectively, if under " heating " set, the temperature value that records is higher than the upper limit, and that just exports the signal that stops to heat; Otherwise,, just send the signal that begins to heat if measured value is lower than lower limit.If under the setting of " refrigeration ", the temperature value that records is higher than the upper limit, just exports the signal that begins to freeze; Otherwise,, just send the signal that stops to freeze if measured value is lower than lower limit.
Consider by the leaving temperature in the register, humidity bound data in and may lose when the power down of artificial input, in circuit, added the read/write circuit of electric erasable RAM, humiture bound data are deposited among this RAM.
Giving of humidity put and control also similar procedure.
Groundwork process of the present invention is as follows, and according to shown in Figure 2, wherein the left side of dotted line is oscillatory circuit and sampling module, and the right is the ROM mapping block, and the below is the control module of humiture.Decide displays temperature or humidity by external signal Sel.Control the counter of sampling module by finite state machine, obtain the count value n that obtains behind cut-in temperature and the humidity sensor according to reference counter, the ROM address counter and the temperature and humidity display counter of temperature and humidity are started working, promptly carry out ROM scanning, value of reading from ROM and n compare until the former greater than the latter, stop the counting of counter, the decimal system humiture value that obtains is shown through LCD by decoding.(control is heating or refrigeration to temperature according to the humiture value that measures and the required operation of carrying out, control is humidification or dries to humidity), according to the humiture maximal value and the minimum value that are deposited with in the register, obtain to control the signal of peripheral hardware by temperature or humidity controller again.Because institute's measured value is shared demonstration with maximum, minimum value, why is worth so control the shown value of LCD by state machine.
Because temperature is the parameter of humidity, and high address is deposited humidity value, low address storage temperature value among the ROM, therefore when measuring humidity, the address of ROM mapping will compensate according to the temperature value that measures, thereby obtains the ROM mapping address of humidity.
At last, we illustrate the design of the state machine of temperature and humidity measurement.According to the principle of temperature and humidity measurement, the maincenter control module of entire circuit is that state machine should comprise following state:
(1) at first allow the RC oscillatory circuit only insert R
RResistance, the instability when avoiding oscillatory circuit to begin makes sample counter remember carry one time earlier;
(2) allow two counters count simultaneously, updn is changed to 1, adds counting, record reference frequency F
rThe number of oscillation of benchmark vibration Fosc when meter is reach one time;
(3) in the RC oscillatory circuit, insert sensor, be similarly and make vibrational stabilization, make the full carry of counting earlier;
(4) two counters are counted simultaneously, and the updn of reference counter is changed to 0, and counter subtracts counting, until being 0, just obtaining inserting the count value n of oscillator behind the sensor this moment, and deposit in the latch;
(5) start ROM address counter and display counter, with existing the data n in the latch to compare, if data then continue counting less than n among the ROM, otherwise counting stops the data among the ROM;
(6) latch data in the display counter, draw final humiture value through decoding unit.
Characteristics of the present invention
1. the sampling temperature of gained or the oscillating impulse count value of humidity, needn't carry out arithmetical operation, only need just compare with the data among the ROM and can get temperature or humidity value, this just greatly reduces complexity of hardware, save hardware spending, also be easy to make integrated circuit;
2. by our method for designing, need only the word length that increases associated counter, and word length and the capacity of corresponding increase ROM, just can improve measuring accuracy, this family chip for the accuracy requirement of design different measuring lays the first stone;
3. to the different model sensor, behind the mapping curve that obtains oscillatory meter numerical value and temperature (humidity), change the value of data among the ROM, needn't change other design, this circuit is just applicable, this just is easy to accomplish when making IC: as long as change version (code-point of ROM), just can be made into new IC.If in the IC manufacturing process, adopt electrically-erasable technology, just the data among the ROM can be rewritten as required, so, can not only realize the replacing needs of different model sensor easily, and can proofread and correct above the instrument that requires measuring error easily;
4. for to reach the purpose that temperature (humidity) is controlled, we, are controlled the measured value that transfinites again according to the setting of heating/refrigeration (humidification/dry) by the artificial bound of setting temperature (humidity).Because in the RAM of electrically-erasable, in case power down, these data still are kept among this RAM, just needn't reset after powering on and can work on the deposit data of humiture bound for we.
Description of drawings
Fig. 1 measures and the control circuit general diagram for temperature and humidity.
Fig. 2 measures and the concrete block diagram of control circuit for temperature and humidity.
Fig. 3 is the temperature sensor RC oscillatory circuit based on Schmidt trigger.
Fig. 4 is the humidity sensor RC oscillatory circuit based on Schmidt trigger.
Fig. 5 is temperature map and display circuit module block diagram.
Fig. 6 is preset temperature and control circuit module block diagram.
Claims (4)
1, a kind of temperature, moisture measurement and control circuit, by RC oscillator module, sample circuit module, humiture mapping and display circuit module, preset with control circuit module and connect and compose through circuit, it is characterized in that the RC oscillator module is connected and composed through circuit by reference oscillation circuit, temperature sensor oscillatory circuit, humidity sensor oscillatory circuit; The sample circuit module is connected and composed through circuit by finite state machine 1, temperature and humidity sample counter, temperature and humidity Puzzle lock storage, timer conter, the temperature and humidity counter is connected with temperature and humidity sensor oscillation circuit, timer conter is connected with reference oscillation circuit, and counter, latch are connected with state machine 1; Mapping and display circuit module are by rom memory, temperature ROM address counter, humidity ROM address counter, comparer, temperature display meter is counted device, the temperature display decoder, the humidity display counter, the humidity display code translator, LCD connects and composes through circuit, comparer is connected with latch with ROM respectively, and with temperature ROM address counter, humidity ROM address counter connects, the temperature display decoder is counted device with temperature display meter successively, temperature ROM address counter connects, the humidity display code translator successively with the humidity display counter, humidity ROM address counter connects; Preset and control circuit by state machine 2, temperature maximal value counter, temperature minimum value counter, temperature controller, humidity maximal value counter, humidity minimum value counter, the humidity controller, the rear end controller connects and composes through circuit, the temperature maximal value is connected with the temperature display decoder with the minimum value counter, temperature controller is counted device with temperature display meter respectively, the temperature maximal value is connected with the minimum value counter, the humidity maximal value is connected with the humidity display code translator with the minimum value counter, the humidity controller respectively with the humidity display counter, the humidity maximal value is connected with the minimum value counter, state machine 2 and temperature, the humidity counter, reference oscillation circuit connects, and is connected with the rear end controller.
2, temperature according to claim 1, humidity telemetry circuit is characterized in that temperature and humidity sensor RC oscillatory circuit is the loose oscillator of sensor access based on Schmidt trigger.
3, temperature according to claim 2, humidity telemetry circuit is characterized in that counting with the vibration of the oscillation circuit that inserts sensor not inserting sensor, thereby write down the number of oscillation of two kinds of different oscillation circuits in identical time interval Δ t.
4, temperature according to claim 3, humidity telemetry circuit, it is characterized in that in ROM, depositing through linearization process and temperature, humidity mapping (enum) data after considering to round up, the temperature value of sampling and humidity value are mapped to data among the ROM, obtain metric temperature, humidity value.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB011261838A CN1162686C (en) | 2001-07-16 | 2001-07-16 | Temperature and humidity measuring and controlling method and circuit |
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|---|---|---|---|
| CNB011261838A CN1162686C (en) | 2001-07-16 | 2001-07-16 | Temperature and humidity measuring and controlling method and circuit |
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| CN1162686C true CN1162686C (en) | 2004-08-18 |
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Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006084092A (en) * | 2004-09-15 | 2006-03-30 | Sanyo Electric Co Ltd | Temperature control device |
| CN101832823B (en) * | 2009-03-13 | 2012-12-05 | 国民技术股份有限公司 | Temperature sensor |
| CN101567767B (en) * | 2009-05-19 | 2011-12-28 | 华为技术有限公司 | Window sampling control method and device |
| CN102095756B (en) * | 2009-12-15 | 2013-05-22 | 台达电子工业股份有限公司 | Humidity sensing circuit with temperature compensation function |
| CN103032934B (en) * | 2011-10-08 | 2015-02-18 | 珠海格力电器股份有限公司 | Automatic control method of air conditioner |
| CN102499430B (en) * | 2011-12-13 | 2013-10-23 | 卧龙电气集团股份有限公司 | Device and method for automatically modifying curing times of controller of bulk curing barn |
| CN103778392A (en) * | 2012-12-13 | 2014-05-07 | 深圳市证通电子股份有限公司 | Data safety device and temperature sensing circuit thereof |
| DE102014211934A1 (en) * | 2014-06-23 | 2015-12-24 | Robert Bosch Gmbh | Sensor device for detecting a moisture of a fluid medium |
| CN105527317B (en) * | 2014-09-29 | 2018-12-25 | 华为技术有限公司 | A kind of method and device of moisture measurement |
| CN108626850B (en) * | 2017-03-20 | 2020-06-12 | 台达电子工业股份有限公司 | Remote intelligent finite-state machine control system of air conditioning equipment |
| CN115248608B (en) * | 2021-04-26 | 2023-05-09 | 华润微集成电路(无锡)有限公司 | Low-power consumption hygrothermograph circuit structure and measurement control method thereof |
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