CN2052535U - Detector for digit display humidity of grain - Google Patents
Detector for digit display humidity of grain Download PDFInfo
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- CN2052535U CN2052535U CN 88202053 CN88202053U CN2052535U CN 2052535 U CN2052535 U CN 2052535U CN 88202053 CN88202053 CN 88202053 CN 88202053 U CN88202053 U CN 88202053U CN 2052535 U CN2052535 U CN 2052535U
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Abstract
The utility model relates to a resistance type measurer with digital display for grain humidity, which belongs to the technical field of measurement. The utility model is mainly composed of a sampling circuit, a logarithmic amplifying circuit, a linear amplifying circuit, an automatic temperature compensation circuit, an analogue digital conversion circuit, a digital display circuit and a direct current-direct current conversion circuit. When the utility model is adopted, the grain humidity can be measured within the temperature range of-10 DEG to + 45 DEG, the measuring range is 9.0%-20.0%, the measuring result adopts the three-position digital display, and the automatic temperature compensation function is provided. A dry battery of 1.5V is used as the electric supply. The utility model has the advantages of portability, simple operation and no adjustment requirement. The utility model is particularly suitable for the measure of the grain humidity when the grain is purchased.
Description
The utility model belongs to the technical field of grain moisture tester.
Before the utility model was succeeded in developing, domestic to have with Wuhan electronic device two factories be tens grain moisture testers (hereinafter to be referred as moisture apparatus) manufacturer of representative, but all resistance-type moisture apparatus products outstanding following shortcoming arranged:
1. pointer header shows water cut, because the serious nonlinear relationship between grain equivalent resistance and the water cut makes dial scale very inhomogeneous, thereby shows that reading accuracy is lower and directly perceived inadequately, misreads easily.
2. need the operator manually to carry out temperature compensation.
The equivalent resistance of grain changes along with variation of temperature, certain grain of promptly equal water cut, and when its temperature was low, equivalent resistance was bigger; Otherwise equivalent resistance is less; Its variable quantity is very big.
Because domestic existing moisture apparatus product does not all carry out linearization process to the relation between grain equivalent resistance and its water cut, so can't carry out auto thermal compensation, can only depend on the operator artificial compensation.Can only rule of thumb be normative reference during with 20 ℃, temperature be whenever fallen 1 ℃, and then the indicator reading being increased by 0.1% is actual water cut; Otherwise, reduce 0.1%.For example survey certain grain for 10 ℃, the indicator reading is 15.0% should be modified to 15.0%+0.1% * 10=16.0%; Otherwise the indicator reading is 15.0% in the time of 30 ℃, then is modified to 15.0%-0.1% * 10=14.0%.This artificial compensation's method was both inconvenient, also made mistakes easily, and when being used to purchase grain, both parties cause contradiction through being everlasting.
3. use operation cumbersome.Existing moisture apparatus product all needs to do some standard and adjustment before use.
Domestic situation front illustrates that the resistance-type numeral of also not seeing our development abroad shows moisture apparatus.There is CD-1 rice wheat moisture content meter in Japan according to reports, but this moisture apparatus is not suitable for the national conditions of China, mainly be the grain that can not be used for measuring water cut lower (9.0%-12.0% scope), and the test specification of 9.0%-12.0% is the main test specification of the Ministry of Electronics Industry of the People's Republic of China (PRC) standard laid down by the ministries or commissions of the Central Government (SJ1151-77) regulation.
In order to overcome the shortcoming of above-mentioned domestic and international moisture apparatus, this utility model is developed a kind of numeral and is shown the grain moisture moisture apparatus.Use operation very simple, do not need any adjustment, use the four joint power supplies of 1.5 volts of dry cells, low price is convenient to buy.This moisture apparatus is easy to carry.
Fig. 1 is an electrical schematic diagram.
Fig. 2 is DC-DC conversion circuit theory diagrams among Fig. 1.
Fig. 3 is a block scheme.
Used device symbolic significance is as follows among Fig. 1, Fig. 2:
IC
1, IC
2, IC
3Be high resistance operating amplifier;
IC
5Be 555 time base circuits;
IC
4, IC
6, IC
7Be respectively 7805,79L05 and 78M12 three terminal regulator;
T
1, T
2, T
3Be transistor;
D
1, D
2, D
5, D
6, D
7Be crystal diode;
D
3Be silicon voltage regulator diode; D
4Be light emitting diode;
B is a pulse transformer, available G
22The coiling of jar shape magnetic core.
E
CBe the supplying cell positive pole.
This utility model technology path is as follows:
We find through several thousand times experiment repeatedly: the equivalent resistance of grain and its content present logarithmic relationship substantially in the main test specification of grain moisture content.
That is: water cut % ≈ K * LnRx
Wherein Rx is the equivalent resistance of grain.
K is a scale-up factor.
We adopt the logarithmic amplifier with uniform temperature compensation to carry out resistance/voltage transitions based on this important discovery, obtain proportional voltage with LnRx, simulate a digital conversion then, show thereby can do numeral to water cut.
Because we have carried out linearization process to the relation of grain equivalent resistance and water cut, institute thinks that auto thermal compensation provides possibility, we utilize the temperature characterisitic of PN junction to realize auto thermal compensation, this utility model is in its operating temperature range under any temperature of (10 ℃-+40 ℃), show that reading is the actual water cut of tested grain, promptly its reading is temperature independent.
The principle of work of this utility model describes in detail:
This utility model belongs to the resistance-type moisture apparatus.It is obtained and grain equivalent resistance R by sample circuit
X(providing) proportional electric signal by two electrodes or other sensors that insert in the grain, after logarithmic amplifier and linear voltage amplifier amplification, obtain and the proportional voltage signal of grain moisture content, carry out analog to digital conversion by large scale integrated chip 7107 again, show the water cut of tested grain at last with three figure place sign indicating numbers.The formation of following division each square frame shown in Figure 3.
(1) sample circuit
Sample circuit is by the equivalent resistance R among Fig. 1
XWith adjustable resistance V
R1(survey the wheat shelves, surveying the corn shelves is V
R2, surveying the paddy shelves is V
R3) and Ro be composed in series.The DC-to-dc change-over circuit provides+and 12 volts of burning voltages are through R
X, R
O, V
R1Produce electric current I
X(because IC
1Pin 2 is the virtual earth end, so I
X≈ (V+12)/(R
o+ R
X+ V
R1) ≈ (V+12)/(Rx), because of Rx＞＞V
R1＞＞R
O).Obviously, grain moisture is lower, R
XBigger, I
XLittler; Otherwise, I
XBigger.
(2) logarithmic amplifier
Logarithmic amplifier is the core of moisture apparatus.Through experimental results demonstrate: in main test specification (9.0% to 16.0%), grain moisture content (%) ≈ KLnRx.Therefore, it is more satisfactory adopting logarithmic amplifier to carry out linearization process.When considering grain moisture content higher (16.0-20.0% scope), following formula has certain error, and we adopt the suitable compensation measure in logarithmic amplifier.V
R4(survey the wheat shelves, surveying the corn shelves is V
R5, surveying the paddy shelves is V
R6) be exactly to be used for compensating the reading of water cut when higher.
Logarithmic amplifier is by the IC among Fig. 1
1, IC
2, T
1, T
2, C
1, C
2, R
2, R
3, R
4Constitute.
(3) linear voltage amplifier
This grade is by the V among Fig. 1
R10(survey the wheat shelves, surveying the corn shelves is V
R11, surveying the paddy shelves is V
R12) R
12, R
13, R
15With 1/2 IC
3Constitute.Adjust V
R10(survey the wheat shelves, surveying the corn shelves is V
R11, surveying the paddy shelves is V
R12) resistance can adjust the voltage gain of this grade.
(4) analog to digital converter
The core of analog to digital converter is three half module number conversion chips 7107.For making 7107 chip operate as normal, need some accessory circuits, the R among Fig. 1
14, R
16, R
17, C
3, C
4, C
5, C
6, C
7It is exactly needed subsidiary component.As long as connect respectively at pin 1 and 26+5 volts and-5 volts of power supplys, pin 36 connects reference voltage, the aanalogvoltage of pin 31 inputs can be converted to numeral output, does three bit digital by three led modules then and shows.
(5) reference voltage generating circuit
(6) auto thermal compensation circuit
The auto thermal compensation circuit is by the R among Fig. 1
10, R
11And D
1Form.As everyone knows, the forward conduction voltage of PN junction reduces (rising) with the rising (reduction) of temperature, has good linear relationship in ± 200 ℃ of scopes, and its linearity is better than 1.0%.When moisture apparatus is worked, if temperature raises (or reduction), then because equivalent resistance R
XReduce (or increase), will make to show that reading increases (or reducing); Meanwhile, D
1Forward voltage drop also make and show that reading reduces (or increasing) with the rising of temperature (or reduction); The two influences jointly, makes to show that reading does not vary with temperature, thereby reaches the effect of auto thermal compensation.
(7) base value is adjusted circuit
Base value is adjusted circuit by R among Fig. 1
5, V
R7And R
9(survey the wheat shelves, surveying the corn shelves is R
6, V
R8, surveying the paddy shelves is R
7, V
R9) form.Adjust V
R7(survey the wheat shelves, surveying the corn shelves is V
R8, surveying the paddy shelves is V
R9) resistance, can make to show that reading increases or reduces.In the practicality, can do trace adjustment, so that measure more accurate according to the difference of different regions and different grain varieties.
(8) cell voltage indicating circuit
Moisture apparatus saves 1.5 volts of battery series-feds with four, and along with the growth of service time, cell voltage descends.After cell voltage is lower than certain numerical value, can have a strong impact on measuring accuracy.Therefore, be provided with the cell voltage indicating circuit.Indicating circuit is by R among Fig. 1
18, R
19, V
R13, R
22, D
5, 1/2 IC
3Form.Adjust V
R13Making the A point voltage is 4.8 volts.If cell voltage is higher than 4.8 volts, light emitting diode D
5Do not work; Otherwise, D
5Bright, should change battery this moment.
(9) DC-to-dc change-over circuit
The moisture apparatus supplying cell is the series connection of 1.5 volts dry cells of 4 joints, and operational amplifier in the circuit and analog to digital conversion circuit require respectively+12 volts with ± 5 volts burning voltage.Therefore, be provided with the DC-to-dc change-over circuit.The change-over circuit schematic diagram as shown in Figure 2.It converts about 5 volts cell voltage to+12 volts and ± 5 volts of three groups of voltage stabilizings outputs, to adapt to the needs of moisture apparatus circuit.
The utility model main application:
The usefulness of hygrometric also was applicable to the quick hygrometrics of unit such as grain depot, flour mill, grain specialist, seeds company when the utility model was best suited for national food department purchase grain.Bigger social benefit is arranged.
Claims (5)
1, the utility model is that a kind of numeral that is made of sample circuit, logarithm amplifying circuit, auto thermal compensation circuit, base value adjustment circuit, linear amplifier circuit, reference voltage generating circuit, analog to digital conversion circuit, digital display circuit and DC-to-dc change-over circuit shows the cereal temperature tester, it is characterized in that having adopted logarithm amplifying circuit, auto thermal compensation circuit, analog to digital conversion circuit and DC-to-dc change-over circuit.
2, show that according to the described numeral of claim 1 the grain moisture tester is characterized in that adopting the logarithm amplifying circuit with temperature compensation measure, by operational amplifier IC
1, operational amplifier IC
2, resistor R
1, R
2, R
3, R
4, capacitor C
1, transistor T
1, T
2, variohm V
R4, V
R5, V
R6Constitute.
3, show that according to the described numeral of claim 1 the grain moisture tester is characterized in that having adopted the auto thermal compensation circuit, by resistor R
10, R
11, diode D
1Constitute.
4, show that according to the described numeral of claim 1 the grain moisture tester is characterized in that having adopted the DC-to-dc change-over circuit, by time base circuit IC
5, negative three terminal regulator IC
6, positive three terminal regulator IC
7, diode D
6, D
7, transistor T
3, resistor R
28, R
29, R
30, capacitor C
11Constitute with pulse transformer B.
5, show that according to the described numeral of claim 1 the grain moisture tester is characterized in that having adopted analog to digital conversion circuit, by large scale integrated chip 7107 and subsidiary component resistor R thereof
14, R
16, R
17, capacitor C
3, C
4, C
6, C
7Form.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88202053 CN2052535U (en) | 1988-03-26 | 1988-03-26 | Detector for digit display humidity of grain |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88202053 CN2052535U (en) | 1988-03-26 | 1988-03-26 | Detector for digit display humidity of grain |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2052535U true CN2052535U (en) | 1990-02-07 |
Family
ID=4837129
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 88202053 Withdrawn CN2052535U (en) | 1988-03-26 | 1988-03-26 | Detector for digit display humidity of grain |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2052535U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100446423C (en) * | 2004-03-12 | 2008-12-24 | 精拓科技股份有限公司 | Energy gap reference voltage circuit arrangement |
| CN103954655A (en) * | 2014-03-28 | 2014-07-30 | 合肥麦稻之星机械科技股份有限公司 | Apparatus for online automatic detection of water content of dried rice through resistivity method |
| CN106442641A (en) * | 2015-08-06 | 2017-02-22 | 盛群半导体股份有限公司 | Humidity sensing method and circuit thereof |
| CN108982593A (en) * | 2018-07-23 | 2018-12-11 | 安徽建筑大学 | The self-adapting measuring method and device of resistance-type grain moisture content instrument wide range resistance value |
-
1988
- 1988-03-26 CN CN 88202053 patent/CN2052535U/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100446423C (en) * | 2004-03-12 | 2008-12-24 | 精拓科技股份有限公司 | Energy gap reference voltage circuit arrangement |
| CN103954655A (en) * | 2014-03-28 | 2014-07-30 | 合肥麦稻之星机械科技股份有限公司 | Apparatus for online automatic detection of water content of dried rice through resistivity method |
| CN106442641A (en) * | 2015-08-06 | 2017-02-22 | 盛群半导体股份有限公司 | Humidity sensing method and circuit thereof |
| CN108982593A (en) * | 2018-07-23 | 2018-12-11 | 安徽建筑大学 | The self-adapting measuring method and device of resistance-type grain moisture content instrument wide range resistance value |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| 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 |