JPS6156460B2 - - Google Patents
Info
- Publication number
- JPS6156460B2 JPS6156460B2 JP8650381A JP8650381A JPS6156460B2 JP S6156460 B2 JPS6156460 B2 JP S6156460B2 JP 8650381 A JP8650381 A JP 8650381A JP 8650381 A JP8650381 A JP 8650381A JP S6156460 B2 JPS6156460 B2 JP S6156460B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- grain
- signal
- moisture
- measuring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000001514 detection method Methods 0.000 claims description 23
- 230000010355 oscillation Effects 0.000 claims description 14
- 238000005259 measurement Methods 0.000 claims description 5
- 230000003321 amplification Effects 0.000 description 7
- 238000003199 nucleic acid amplification method Methods 0.000 description 7
- 230000001419 dependent effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000012937 correction Methods 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/045—Circuits
- G01N27/046—Circuits provided with temperature compensation
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Description
【発明の詳細な説明】
本発明は発振回路の温度補償機能を備えた穀物
水分測定装置、特に発振回路に起因する温度ドリ
フトの影響を除去した穀物の含水率を測定するた
めの高周波式穀物水分測定装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a grain moisture measuring device equipped with an oscillation circuit temperature compensation function, and particularly a high-frequency grain moisture measuring device for measuring grain moisture content that eliminates the influence of temperature drift caused by the oscillation circuit. Concerning a measuring device.
穀物の水分値を測定するための装置として高周
波発振器を含む高周波式水分計が知られている。
この水分計においては、一定容積の穀物が電極容
器中に挿入され、電極間に高周波電圧を加えて、
穀物の水分値に依存するその静電容量を測定する
ことにより穀物の水分値に比例した高周波電圧を
検出し、この高周波電圧を検波して直流電圧に変
換し、この直流電圧値から穀物の水分率を測定し
ている。しかしながら、穀物の含水率は温度依存
性を有しているので、一般にサーミスタにより穀
物の温度を検出することで、穀物の温度補正が成
されているが、高周波式水分計自体の温度ドリフ
トによる温度補正は成されていない。すなわち、
高周波水分計は被測定穀物に高周波信号を加える
高周波発振器、および穀物の水分率を測定する為
の水分測定回路から成る。高周波発振器はトラン
ジスタ、ダイオード等の温度依存性を有する回路
素子によつて構成される為に、これら素子に起因
する温度ドリフトを補償しなければ所定出力レベ
ルの高周波電圧を穀物に加えることができないの
で、結果的に正確な水分率の測定は得られない。 A high-frequency moisture meter including a high-frequency oscillator is known as a device for measuring the moisture value of grain.
In this moisture meter, a certain volume of grain is inserted into an electrode container, and a high frequency voltage is applied between the electrodes.
By measuring the capacitance, which depends on the moisture value of the grain, a high frequency voltage proportional to the moisture value of the grain is detected, and this high frequency voltage is detected and converted to a DC voltage, and the moisture content of the grain is determined from this DC voltage value. The rate is being measured. However, since the moisture content of grains is temperature dependent, grain temperature compensation is generally achieved by detecting the grain temperature using a thermistor, but temperature drift due to the temperature drift of the high-frequency moisture meter itself No corrections have been made. That is,
A high-frequency moisture meter consists of a high-frequency oscillator that applies a high-frequency signal to the grain to be measured, and a moisture measuring circuit for measuring the moisture content of the grain. Since a high-frequency oscillator is composed of circuit elements such as transistors and diodes that are temperature-dependent, it is not possible to apply a high-frequency voltage of a predetermined output level to the grain unless the temperature drift caused by these elements is compensated for. As a result, accurate moisture content measurements cannot be obtained.
従つて、本発明の目的は発振回路に起因する温
度ドリフトを補償した高周波式穀物水分測定装置
を提供することである。 SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a high frequency grain moisture measuring device that compensates for temperature drift caused by an oscillating circuit.
以下、本発明を添付図面に示す一実施例を参照
して詳細に説明する。 Hereinafter, the present invention will be described in detail with reference to an embodiment shown in the accompanying drawings.
第１図は、穀物の水分率を測定するための高周
波式水分測定装置であつて、高周波発振回路の温
度ドリフトを補償するための温度補償機能を備え
ている。同図において、１は被測定用の穀物を介
在させるための一対の電極、３は穀物に高周波信
号を加えることによつて穀物から得られる被測定
信号を検出、検波することにより穀物の含水率に
相当する直流電圧ＶDCを発生する為の水分測定回
路である。この測定回路は公知のものでよいが、
例えば本出願人が本出願と同日に出願した「温度
補償機能を備えた測定装置」と題する特開昭57−
200843の検出回路、検波回路および減算回路から
成る回路構成を使用することができる。５は被測
定穀物が所定の温度および含水率状態にある時の
インピーダンス値に相当するインピーダンスを有
する基準インピーダンス回路である。７は基準イ
ンピーダンスに基づく被測定信号から基準インピ
ーダンスの含水率に相当する直流電圧ＶDを発生
するための検出回路であつて、水分測定回路３と
検出回路７の出力の温度による変化の割合が同一
になるよう選択される。９は基準電源１３からの
基準電圧Vrefと検出電圧ＶDを比較し検出電圧Ｖ
Dを一定の値とするような出力ＶCを発生する。１
５は穀物および、基準インピーダンス回路５に対
し高周波信号を供給する高周波発振回路である。
発振回路１５は比較回路９の出力信号ＶCに基づ
きその高周波発振出力レベルが制御されるもので
ある。すなわち、１７は高周波発振器であり、そ
の出力はFET１９のゲート電極に中点が接続さ
れた分圧回路の一端に接続されている。FETの
ドレイン電極は増巾器２１に接続されている。出
力ＶCによりFETのゲート電圧が制御されると、
穀物および基準インピーダンス回路に対し高周波
信号を供給する増巾器２１の出力レベルがＶDを
一定とするように調整される。 FIG. 1 shows a high-frequency moisture measuring device for measuring the moisture content of grain, and is equipped with a temperature compensation function to compensate for temperature drift of a high-frequency oscillation circuit. In the figure, 1 is a pair of electrodes for interposing the grain to be measured, and 3 is a high-frequency signal that is applied to the grain to detect the signal to be measured obtained from the grain. This is a moisture measuring circuit for generating a DC voltage V DC corresponding to . This measurement circuit may be a known one, but
For example, the present applicant filed a patent application entitled ``Measuring device with temperature compensation function'' on the same day as the present application.
A circuit configuration consisting of a 200843 detection circuit, a detection circuit, and a subtraction circuit can be used. 5 is a reference impedance circuit having an impedance corresponding to an impedance value when the grain to be measured is at a predetermined temperature and moisture content state. 7 is a detection circuit for generating a DC voltage V D corresponding to the moisture content of the reference impedance from the signal to be measured based on the reference impedance, and the rate of change due to temperature in the outputs of the moisture measuring circuit 3 and the detection circuit 7 is are selected to be the same. 9 compares the reference voltage Vref from the reference power supply 13 and the detection voltage V D and determines the detection voltage V
Generate an output V C that makes D a constant value. 1
Reference numeral 5 denotes a high frequency oscillation circuit that supplies a high frequency signal to the grain and reference impedance circuit 5.
The high frequency oscillation output level of the oscillation circuit 15 is controlled based on the output signal V C of the comparison circuit 9. That is, 17 is a high frequency oscillator, the output of which is connected to one end of a voltage dividing circuit whose midpoint is connected to the gate electrode of FET 19. The drain electrode of the FET is connected to an amplifier 21. When the FET gate voltage is controlled by the output V C ,
The output level of amplifier 21, which supplies the high frequency signal to the grain and reference impedance circuits, is adjusted to keep V D constant.
この点を数式を用いて説明する。 This point will be explained using a mathematical formula.
K1：被測定物のインピーダンスの大きさから
決まる比例定数。 K 1 : Constant of proportionality determined by the impedance of the object to be measured.
K2：基準インピーダンス回路５の大きさから
決まる比例定数
Vosc：発振器１７の高周波出力電圧
ａ：FET１９の増巾率
ｂ：増巾器２１の増巾率
ｃ：水分測定回路３の増巾率
ｄ：検出回路７の増巾率
とする。また、温度変化により、それぞれ
Vosc→αVosc ａ→a′
ｂ→βｂ ＶDC→V′DC
ｃ→γｃ ＶD→V′D
ｄ→γｄ
に変化したとする。ここで、水分測定回路３と検
出回路７の増巾率ｃおよびｄの温度による変化の
割合が同一となるように構成されているので、増
巾率ｃおよびｄの温度係数はγとなつている。 K 2 : Proportionality constant determined by the size of the reference impedance circuit 5 Vosc: High frequency output voltage of the oscillator 17 a: Amplification rate of the FET 19 b: Amplification rate of the amplifier 21 c: Amplification rate of the moisture measuring circuit 3 d : The amplification rate of the detection circuit 7. It is also assumed that due to a temperature change, the values change to Vosc→αVosc a→a′ b→βb V DC →V′ DC c→γc V D →V′ D d→γd. Here, since the moisture measuring circuit 3 and the detection circuit 7 are configured so that the rate of change due to temperature in the amplification factors c and d is the same, the temperature coefficient of the amplification factors c and d is γ. There is.
ＶDC＝Vosc・ａ・ｂ・ｃ・K1 …(1)
ＶD＝Vosc・ａ・ｂ・ｄ・K2 …(2)
であり、検出回路７の温度変化時の出力V′Dは
V′D＝αVosc・a′・βｂ・γｄ・K2 …(3)
a′＝Ｖ′Ｄ／αＶｏｓｃ・βｂ・γｄ・Ｋ２ …(4)
また、
V′DC＝αVosc・a′・βｂ・γｃ・K1 …(5)
(4)を代入すると
V′DC＝αVosc・Ｖ′Ｄ／αＶｏｓｃ・βｂ・γｄ・
Ｋ２
・βｂ・γｃ・K1＝ｃＫ１／ｄＫ２・V′D…(6
)
ＶD＝V′Dとなるように制御されているのである
から、(6)式は
V′DC＝ｃＫ１／ｄＫ２ＶD …(7)
ＶＤ／ＶＤＣ＝Ｖｏｓｃ・ａ・ｂ・ｄ・Ｋ２／Ｖｏｓ
ｃ・ａ・ｂ・ｃ・Ｋ１＝ｄＫ２／ｃＫ１…(8)
ＶD＝ｄＫ２／ｃＫ１・ＶDC …(9)
(9)式を(7)式に代入すると
V′DC＝ｃＫ１／ｄＫ２・ｄＫ２／ｃＫ１・ＶDC…(10
)
したがつて
V′DC＝ＶDC …(11)
上記説明から明らかなとおり、
検出回路７の検出電圧ＶDは一定値に保たれ、発
振回路１５自体の温度ドリフトは補償される。そ
れ故、電極１間に置かれた穀物には常に一定の高
周波電圧が加えられるので、水分測定回路３の出
力として得られる直流電圧ＶDCは発振回路の温度
ドリフトの影響を受けない正確な含水率を示すこ
とができる。 V DC = Vosc・a・b・c・K 1 …(1) V D = Vosc・a・b・d・K 2 …(2), and the output V′ D of the detection circuit 7 when the temperature changes is V' D = αVosc・a′・βb・γd・K 2 …(3) a′=V′ D /αVosc・βb・γd・K 2 …(4) Also, V′ DC = αVosc・a′・βb・γc・K 1 …(5) Substituting (4), V′ DC = αVosc・V′ D /αVosc・βb・γd・
K 2・βb・γc・K 1 = cK 1 /dK 2・V′ D …(6
) Since it is controlled so that V D = V' D , equation (6) is V' DC = cK 1 /dK 2 V D ...(7) V D /V DC = Vosc・a・b・d・K 2 /Vos
c・a・b・c・K 1 =dK 2 /cK 1 …(8) V D =dK 2 /cK 1・V DC …(9) Substituting equation (9) into equation (7) gives V′ DC =cK 1 /dK 2・dK 2 /cK 1・V DC …(10
) Therefore, V' DC =V DC (11) As is clear from the above explanation, the detection voltage V D of the detection circuit 7 is kept at a constant value, and the temperature drift of the oscillation circuit 15 itself is compensated. Therefore, since a constant high-frequency voltage is always applied to the grain placed between the electrodes 1, the direct current voltage V DC obtained as the output of the moisture measuring circuit 3 has an accurate moisture content that is not affected by the temperature drift of the oscillation circuit. rate can be shown.
第２図は水分測定回路３および検出回路７の回
路構成図であり、同図においては、水分測定回路
３及び検出回路７は同一の回路構成を有してい
る。また同図は、前述の本出願人による同日出願
に示した検出回路、検波回路および減算回路を、
本考案の水分測定回路３および検波回路７に適用
したものである。同図において、２３，２４はそ
の増巾率の温度依存性の等しいトランジスタ、２
５，２６はトランジスタ２３および２４のコレク
タにおける直流分電圧を固定するための比較回
路、２７，２９はそのアノード側に接続された平
滑回路と共に検波回路を構成する温度依存性の同
一なダイオード、３１，３３は減算回路、３５は
検波回路の出力の直流成分を除去するために減算
回路に接続される基準電源である。 FIG. 2 is a circuit configuration diagram of the moisture measurement circuit 3 and the detection circuit 7, and in the figure, the moisture measurement circuit 3 and the detection circuit 7 have the same circuit configuration. The same figure also shows the detection circuit, detection circuit, and subtraction circuit shown in the above-mentioned application filed on the same day by the present applicant.
This is applied to the moisture measuring circuit 3 and the detection circuit 7 of the present invention. In the figure, 23 and 24 are transistors whose amplification factors have equal temperature dependence;
5 and 26 are comparison circuits for fixing the DC voltage at the collectors of the transistors 23 and 24; 27 and 29 are temperature-dependent identical diodes that together with the smoothing circuit connected to the anode side constitute a detection circuit; 31; , 33 is a subtraction circuit, and 35 is a reference power supply connected to the subtraction circuit in order to remove the DC component of the output of the detection circuit.
以上説明したように、本発明の穀物水分率測定
装置によれば、発振回路の温度ドリフトの影響を
除去することができるので、正確な穀物の水分率
測定が可能となる。 As explained above, according to the grain moisture content measuring device of the present invention, it is possible to eliminate the influence of temperature drift of the oscillation circuit, and thus it is possible to accurately measure the moisture content of grain.
第１図は本発明の一実施例の発振回路の温度補
償機能を備えた高周波式穀物水分測定装置の回路
構成図、第２図は本考案の水分測定装置の水分測
定回路および検出回路の回路構成図である。
５：基準インピーダンス回路、７：検出回路、
９：比較回路、１３：基準電源、１７：発振器、
１９：FET、２１：増巾器。
FIG. 1 is a circuit diagram of a high-frequency grain moisture measuring device equipped with an oscillation circuit temperature compensation function according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a moisture measuring circuit and a detection circuit of the moisture measuring device of the present invention. FIG. 5: Reference impedance circuit, 7: Detection circuit,
9: Comparison circuit, 13: Reference power supply, 17: Oscillator,
19: FET, 21: Amplifier.
Claims (1)
定を行うための測定回路、 所定の基準インピーダンスを有する基準インピ
ーダンス回路、 前記被測定穀物および前記基準インピーダンス
回路に交流信号を供給する高周波発振回路、 前記測定回路とほぼ同じ温度特性を有し前記基
準インピーダンス回路からの信号に基づく検出信
号を出力する検出回路、 前記検出信号と所定の基準信号とを比較し、前
記基準インピーダンス回路からの信号が所定の値
になるように前記発振回路の出力レベルを制御す
る比較回路を有する前記発振回路の温度補償機能
を備えた高周波穀物水分測定装置。 ２ 前記測定回路と前記検出回路は同一の回路構
成を有する特許請求の範囲第１項記載の測定装
置。[Scope of Claims] 1. A measuring circuit for measuring the moisture content of grain based on a signal from the grain to be measured, a reference impedance circuit having a predetermined reference impedance, and supplying an alternating current signal to the grain to be measured and the reference impedance circuit. a high-frequency oscillation circuit that outputs a detection signal based on a signal from the reference impedance circuit, which has almost the same temperature characteristics as the measurement circuit; a detection circuit that compares the detection signal with a predetermined reference signal, A high-frequency grain moisture measuring device comprising a comparator circuit for controlling an output level of the oscillation circuit so that a signal from the oscillation circuit has a predetermined value, and a temperature compensation function for the oscillation circuit. 2. The measuring device according to claim 1, wherein the measuring circuit and the detecting circuit have the same circuit configuration.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8650381A JPS57200842A (en) | 1981-06-05 | 1981-06-05 | Cereals moisture measuring device equipped with temperature compensating function for oscillating circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8650381A JPS57200842A (en) | 1981-06-05 | 1981-06-05 | Cereals moisture measuring device equipped with temperature compensating function for oscillating circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57200842A JPS57200842A (en) | 1982-12-09 |
| JPS6156460B2 true JPS6156460B2 (en) | 1986-12-02 |
Family
ID=13888777
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8650381A Granted JPS57200842A (en) | 1981-06-05 | 1981-06-05 | Cereals moisture measuring device equipped with temperature compensating function for oscillating circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57200842A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63127568U (en) * | 1986-09-03 | 1988-08-22 |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100289335B1 (en) * | 1998-06-02 | 2001-05-02 | 최병준 | Nondestructive measuring apparatus for moisture content using phase difference |
-
1981
- 1981-06-05 JP JP8650381A patent/JPS57200842A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63127568U (en) * | 1986-09-03 | 1988-08-22 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57200842A (en) | 1982-12-09 |
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