JPH0577246B2

JPH0577246B2 -

Info

Publication number: JPH0577246B2
Application number: JP62182282A
Authority: JP
Inventors: Hisayoshi Masuda
Original assignee: Tokyo Shibaura Electric Co Ltd
Current assignee: Toshiba Corp
Priority date: 1987-07-23
Filing date: 1987-07-23
Publication date: 1993-10-26
Also published as: JPS6428516A

Description

[Detailed description of the invention]

［発明の目的］（産業上の利用分野）本発明は、工業用計測器等における温度補償回
路に関するものである。（従来の技術）種々の工業用計測器等では、一般に計測環境の
温度による影響を補償する温度補償回路が設けら
れている。第３図は従来の温度補償回路の構成を示してい
る。温度センサ１により主センサ４（工業用計測
器）の計測環境の温度が検出され、温度信号
PETとして出力されている。また、この温度信
号PETは反転増幅器２で反転され反転信号NET
として出力されている。温度センサ１の出力端と反転増幅器２の出力端
との間には摺動抵抗６１が介挿されており、その
摺動子電圧信号CETが温度補償信号として加重
加算回路５にて主センサ４の計測信号に加重され
る。加重加算回路５のオペアンプ５１からは温度
補償後の主センサ計測信号が出力されるようにな
つている。第４図はこの第３図の回路の温度補償の作用特
性を示している。上記温度信号PETとその反動信号NETとは温
度に対する変化が逆の信号であり、また、摺動子
電圧信号CETは摺動子の位置により符号及び大
きさが異なる温度補償信号となつている。従つ
て、摺動子の位置を調整することにより温度補償
範囲を温度信号PETと反転信号NETとの間で変
え、主センサ４の温度特性を改善することができ
る。しかしながら、上記工業用計測器（主センサ
４）は、幅広い温度環境下で使用されるものであ
る。このため主センサが、特に第５図に符号Ａで
示すような非直線的な温度特性を持つ場合、温度
補償後の特性Ｂは、０℃以下の低温領域では比較
的平坦な特性を示すものの、０℃以上の高温領域
では温度の上昇につれて垂下する特性を持ち、良
好な温度補償ができない。（発明が解決しようとする問題点）上述のように、従来の温度補償回路は、計測器
の特性を考慮することなく、低温領域、高温領域
によらず一律に温度補償をするようにしていたの
で、精確な温度補償とすることができないという
問題点があつた。本発明は上記問題点に鑑みてなされたものであ
り、その目的は、高温領域、低温領域に応じて精
確な温度補償を簡易な回路構成によつて行うこと
のできる温度補償回路を提供することにある。［発明の構成］（問題点を解決するための手段）上記目的を達成するために、本発明は、種々の
物理量を計測して得られる計測信号に対してその
計測環境の温度に応じた温度補償をする回路であ
つて、前記計測環境の温度を検出する温度検出手
段と、この温度検出手段で得られた温度検出信号
の極性を反転して反転信号として出力する信号反
転手段と、それぞれが所定の抵抗を介して前記温
度検出信号とその反転信号とを接続するととも
に、温度検出信号が反転信号よりも大きい場合と
反転信号が温度検出信号よりも大きい場合とでは
導通状態が相互に反転する２つのスイツチ手段
と、前記所定の抵抗を介して出力される温度補償
信号を前記計測信号に加算する加算手段とを有す
ることを特徴とする。（作用）本発明では、計測環境の温度検出信号とその反
転信号が得られ、温度検出信号が反転信号より大
きい場合と小さい場合とで別個独立して温度補償
されている。これにより精確な温度補償が可能と
なる。（実施例）第１図は本発明が適用された温度補償回路の一
実施例の構成を示している。本実施例は、温度センサ１と、この温度センサ
１の温度信号PETの極性を反転した反転信号
NETを得る反転増幅器２と、温度信号PETと反
転信号NETの大小に応じて自動的に温度補償の
レンジ切換が可能なスイツチ回路３とを備えてい
る。主センサ４は種々の物理量（例えば、物体の
歪、重量等）を計測しており、この計測信号には
加重加算回路５でスイツチ回路３からの温度補償
信号（摺動子電圧信号CET）が加重されて温度
補償されるようになつている。スイツチ回路３は、２つのPNPトランジスタ
３１，３２と、２つのNPNトランジスタ３３，
３４とを備えている。 PNPトランジスタ３１と３２のベースは抵抗
３５を介して接地され、またNPNトランジスタ
のベースには抵抗３６を介してバイアス電圧V₁
が供給されている。トランジスタ３１と３４の各
エミツタには温度センサ１の温度信号PETが、
トランジスタ３２と３３の各エミツタには反転増
幅器２の反転信号NETがそれぞれ供給されてい
る。そして、トランジスタ３１と３３のコレクタ
間には摺動抵抗３７が、またトランジスタ３２と
３４のコレクタ間には摺動抵抗３８がそれぞれ介
挿されている。これら摺動子抵抗３７，３８の摺動子電圧信号
Ｃ１ET，Ｃ２ETは抵抗５５，５４を介して加重
加算回路５で主センサ４からの計測信号に加算さ
れ、計測信号の温度補償がされる。すなわち、スイツチ回路３は、温度センサ１の
温度信号PETと反転増幅器２から出力される温
度信号PETの反転信号NETとをそれぞれ摺動抵
抗３７，３８を介して接続するとともに、トラン
ジスタ３１，３３から成るスイツチ回路とトラン
ジスタ３２，３４から成るスイツチ回路とで構成
されている。そして、温度信号PETが反転信号
NETよりも高い場合には、トランジスタ３１，
３３が導通し摺動抵抗３７を介して出力される温
度補償信号が加重加算回路５にて主センサ４の計
測信号に加重されて温度補償がされる。逆に反転
信号NETが温度信号PETよりも高い場合には、
トランジスタ３２，３４が導通し摺動抵抗３８を
介して出力される温度補償信号が加重加算回路５
にて主センサ４の計測信号に加重されて温度補償
がされる。次にその作用を第２図を参照して説明する。第２図において、２つのNPNトランジスタ
Qa，Qbの特性を同等とすると、各トランジスタ
Qa，Qbのコレクタ電流Ic（＝Ica＝Icb）は、 Ic＝I₀・exp（ｑ・Vbe／ｋ・Ｔ） ……(1) となる。ここで、I₀は定数、ｑは電子の電荷の絶
対値、Vbeはベース・エミツタ間電圧、ｋはボル
ツマン定数、Ｔは絶対温度である。２つのトランジスタQa，Qbのコレクタ電流の
比Ica／Icbは次の(2)式のようになる。 Ica／Icb＝exp｛ｑ（Eb−Ea）／kT｝ ……(2) 今、温度を25℃とすると、kT／ｑ≒26ｍＶで
あるから、(2)式によりIca／IcbとEb−Eaとの関
係は次表のように求まる。 [Object of the Invention] (Industrial Application Field) The present invention relates to a temperature compensation circuit in an industrial measuring instrument or the like. (Prior Art) Various industrial measuring instruments and the like are generally provided with a temperature compensation circuit that compensates for the influence of the temperature of the measurement environment. FIG. 3 shows the configuration of a conventional temperature compensation circuit. Temperature sensor 1 detects the temperature of the measurement environment of main sensor 4 (industrial measuring instrument), and sends a temperature signal.
It is output as PET. Also, this temperature signal PET is inverted by the inverting amplifier 2 and the inverted signal NET
It is output as . A sliding resistor 61 is inserted between the output end of the temperature sensor 1 and the output end of the inverting amplifier 2, and the slider voltage signal CET is sent to the main sensor 4 by the weighted addition circuit 5 as a temperature compensation signal. The measurement signal is weighted. The operational amplifier 51 of the weighted addition circuit 5 outputs a temperature-compensated main sensor measurement signal. FIG. 4 shows the operational characteristics of the temperature compensation of the circuit of FIG. The temperature signal PET and its reaction signal NET are signals whose changes with respect to temperature are opposite to each other, and the slider voltage signal CET is a temperature compensation signal whose sign and magnitude differ depending on the position of the slider. Therefore, by adjusting the position of the slider, the temperature compensation range can be changed between the temperature signal PET and the inverted signal NET, and the temperature characteristics of the main sensor 4 can be improved. However, the industrial measuring instrument (main sensor 4) is used in a wide range of temperature environments. Therefore, if the main sensor has a nonlinear temperature characteristic, especially as shown by the symbol A in Figure 5, the characteristic B after temperature compensation will be a relatively flat characteristic in the low temperature region below 0°C. , in a high temperature range of 0° C. or higher, it has a characteristic of drooping as the temperature rises, and good temperature compensation cannot be achieved. (Problems to be solved by the invention) As mentioned above, the conventional temperature compensation circuit performs temperature compensation uniformly regardless of the low temperature region or high temperature region, without considering the characteristics of the measuring instrument. Therefore, there was a problem that accurate temperature compensation could not be achieved. The present invention has been made in view of the above problems, and its purpose is to provide a temperature compensation circuit that can perform accurate temperature compensation depending on high temperature and low temperature regions with a simple circuit configuration. It is in. [Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides temperature control based on the temperature of the measurement environment for measurement signals obtained by measuring various physical quantities. The compensation circuit includes a temperature detection means for detecting the temperature of the measurement environment, and a signal inversion means for inverting the polarity of the temperature detection signal obtained by the temperature detection means and outputting it as an inverted signal. The temperature detection signal and its inverted signal are connected through a predetermined resistor, and the conduction state is mutually inverted when the temperature detection signal is larger than the inverted signal and when the inverted signal is larger than the temperature detection signal. The present invention is characterized in that it includes two switch means and an addition means for adding a temperature compensation signal outputted via the predetermined resistor to the measurement signal. (Function) In the present invention, a temperature detection signal of the measurement environment and its inverted signal are obtained, and temperature compensation is performed separately and independently when the temperature detection signal is larger than the inverted signal and when it is smaller than the inverted signal. This allows accurate temperature compensation. (Embodiment) FIG. 1 shows the configuration of an embodiment of a temperature compensation circuit to which the present invention is applied. This embodiment uses a temperature sensor 1 and an inverted signal obtained by inverting the polarity of the temperature signal PET of this temperature sensor 1.
NET, and a switch circuit 3 that can automatically switch the temperature compensation range according to the magnitude of the temperature signal PET and the inverted signal NET. The main sensor 4 measures various physical quantities (for example, strain and weight of an object), and a weighted addition circuit 5 adds a temperature compensation signal (slider voltage signal CET) to this measurement signal from the switch circuit 3. It is weighted and temperature compensated. The switch circuit 3 includes two PNP transistors 31 and 32, two NPN transistors 33,
It is equipped with 34. The bases of the PNP transistors 31 and 32 are grounded through a resistor 35, and the base of the NPN transistor is connected to a bias voltage V ₁ through a resistor 36.
is supplied. The temperature signal PET from the temperature sensor 1 is applied to each emitter of the transistors 31 and 34.
An inverted signal NET from the inverting amplifier 2 is supplied to each emitter of the transistors 32 and 33, respectively. A sliding resistor 37 is inserted between the collectors of the transistors 31 and 33, and a sliding resistor 38 is inserted between the collectors of the transistors 32 and 34, respectively. The slider voltage signals C1ET and C2ET of these slider resistors 37 and 38 are added to the measurement signal from the main sensor 4 via the resistances 55 and 54 in the weighted addition circuit 5, and the measurement signal is subjected to temperature compensation. That is, the switch circuit 3 connects the temperature signal PET of the temperature sensor 1 and the inverted signal NET of the temperature signal PET outputted from the inverting amplifier 2 via sliding resistors 37 and 38, respectively, and and a switch circuit consisting of transistors 32 and 34. Then, the temperature signal PET is an inverted signal
If higher than NET, transistor 31,
33 becomes conductive, and the temperature compensation signal outputted via the sliding resistor 37 is weighted by the measurement signal of the main sensor 4 in the weighting addition circuit 5 to perform temperature compensation. Conversely, if the inverted signal NET is higher than the temperature signal PET,
When the transistors 32 and 34 become conductive, the temperature compensation signal output via the sliding resistor 38 is sent to the weighted addition circuit 5.
The measurement signal from the main sensor 4 is weighted and temperature compensated. Next, its operation will be explained with reference to FIG. In Figure 2, two NPN transistors
If the characteristics of Qa and Qb are the same, each transistor
The collector currents Ic (=Ica=Icb) of Qa and Qb are as follows: Ic=I ₀ · exp (q · Vbe / k · T) ... (1). Here, I ₀ is a constant, q is the absolute value of the electron charge, Vbe is the base-emitter voltage, k is Boltzmann's constant, and T is the absolute temperature. The ratio Ica/Icb of the collector currents of the two transistors Qa and Qb is expressed by the following equation (2). Ica/Icb=exp{q(Eb-Ea)/kT}...(2) Now, if the temperature is 25℃, kT/q≒26mV, so Ica/Icb and Eb-Ea can be calculated by equation (2). The relationship with is calculated as shown in the table below.

【表】上表から理解できるようにEa＞Ebの場合、Eb
−Eaが負のときにはコレクタ電流Icaはほとんど
流れず、コレクタ電流Icbのみが流れる。逆にEa
＜Ebの場合、Eb−Eaが正の値で大きくなるにつ
れてコレクタ電流Icaが増えIcbはほとんど流れな
い。つまり、トランジスタQa，QbはEb−Eaの
値が０より大か、小かによつてON、OFFが入れ
替わる。従つて、第１図において温度信号PET＞反転
信号NETの場合、すなわち温度が０℃以上（以
下、高温領域という）のときには、トランジスタ
３１，３３は共にオンとなり、摺動抵抗３７に電
流が流れる。このときトランジスタ３２，３４は
オフである。そして、抵抗３７の摺動子を調整す
ることによつて所望の摺動子電圧信号Ｃ１ETが
得られ、この摺動子電圧信号Ｃ１ETが主センサ
４の計測信号に加重されて高温領域での温度補償
がされる。一方、温度信号PET＜反転信号NETの場合、
すなわち温度が０℃以下（以下、低温領域とい
う）のときには、トランジスタ３２，３４が共に
オンとなり、摺動抵抗３８に電流が流れる。この
とき、トランジスタ３１，３３はオフである。そ
して、抵抗３８の摺動子を調整することによつて
所望の摺動子電圧信号Ｃ２ETが得られ、この摺
動子電圧信号Ｃ２ETが主センサ４の計測信号に
加重されて低温領域での温度補償がされる。そして、前述した表の説明からも明らかなよう
に、トランジスタ３１，３３とトランジスタ３
２，３４とのオン−オフの切換点は、摺動抵抗３
７と摺動抵抗３８との抵抗比で決定されるので、
温度センサ１の出力信号が電源電圧の変動等によ
つて変動しても切換点まで変動することはない。このように本実施例によれば、高温領域と低温
領域とで別個に独立して温度補償をすることがで
きるので、温度の高低に影響されずに精確に温度
補償をすることができる。しかも、本実施例によ
れば、高価なアンプや比較器等を用いずに簡単な
回路構成で精確な温度補償が可能となる。［発明の効果］以上説明したように本発明によれば、高価なア
ンプや比較器等を用いることなく、簡単な回路構
成によつて計測環境の温度検出信号とその反転信
号の大小に応じて個別に正確な温度補償をするこ
とができる。また、本発明の２つのスイツチ手段は、温度検
出手段の温度検出信号とその反転信号とを所定の
抵抗を介してそれぞれ接続して構成されており、
その切換点がこの抵抗比により決定できるので、
温度検出手段の温度検出信号が電源電圧の変動等
によつて変動しても２つのスイツチ手段間の導通
状態の切換点が変動することはなく、正確な測定
が可能となる。[Table] As can be understood from the table above, if Ea > Eb, Eb
When −Ea is negative, almost no collector current Ica flows, and only collector current Icb flows. On the other hand, Ea
In the case of <Eb, as Eb-Ea increases with a positive value, collector current Ica increases and Icb hardly flows. In other words, transistors Qa and Qb are switched between ON and OFF depending on whether the value of Eb-Ea is larger or smaller than 0. Therefore, in FIG. 1, when the temperature signal PET>the inverted signal NET, that is, when the temperature is 0° C. or higher (hereinafter referred to as a high temperature region), both transistors 31 and 33 are turned on, and a current flows through the sliding resistor 37. . At this time, transistors 32 and 34 are off. By adjusting the slider of the resistor 37, a desired slider voltage signal C1ET is obtained, and this slider voltage signal C1ET is weighted with the measurement signal of the main sensor 4 to determine the temperature in the high temperature region. Compensation will be provided. On the other hand, if temperature signal PET < inverted signal NET,
That is, when the temperature is below 0° C. (hereinafter referred to as a low temperature region), both transistors 32 and 34 are turned on, and current flows through the sliding resistor 38. At this time, transistors 31 and 33 are off. By adjusting the slider of the resistor 38, a desired slider voltage signal C2ET is obtained, and this slider voltage signal C2ET is weighted with the measurement signal of the main sensor 4 to adjust the temperature in the low temperature region. Compensation will be provided. As is clear from the explanation of the table above, transistors 31 and 33 and transistor 3
The on-off switching point between 2 and 34 is the sliding resistance 3.
7 and the sliding resistance 38, so
Even if the output signal of the temperature sensor 1 fluctuates due to fluctuations in the power supply voltage, etc., it will not fluctuate to the switching point. As described above, according to this embodiment, temperature compensation can be performed separately and independently in the high temperature region and the low temperature region, so that temperature compensation can be performed accurately without being affected by the height of the temperature. Moreover, according to this embodiment, accurate temperature compensation can be performed with a simple circuit configuration without using expensive amplifiers, comparators, etc. [Effects of the Invention] As explained above, according to the present invention, the temperature detection signal of the measurement environment and its inverted signal can be detected using a simple circuit configuration without using expensive amplifiers or comparators. Accurate temperature compensation can be performed individually. Further, the two switch means of the present invention are configured by connecting the temperature detection signal of the temperature detection means and its inverted signal via a predetermined resistor, respectively.
Since the switching point can be determined by this resistance ratio,
Even if the temperature detection signal of the temperature detection means fluctuates due to fluctuations in the power supply voltage or the like, the switching point of the conduction state between the two switch means does not fluctuate, making accurate measurement possible.

[Brief explanation of the drawing]

第１図は本発明が適用された温度補償回路の一
実施例の構成図、第２図は同実施例の動作原理の
説明図、第３図は従来例の構成図、第４図及び第
５図は従来例の作用説明図である。１……温度センサ、２……反転増幅器、３……
スイツチ回路、３１，３２……PNPトランジス
タ、３３，３４……NPNトランジスタ、３７，
３８……摺動抵抗、４……主センサ、５……加重
加算回路。 Fig. 1 is a block diagram of an embodiment of a temperature compensation circuit to which the present invention is applied, Fig. 2 is an explanatory diagram of the operating principle of the same embodiment, Fig. 3 is a block diagram of a conventional example, and Figs. FIG. 5 is an explanatory diagram of the operation of the conventional example. 1...Temperature sensor, 2...Inverting amplifier, 3...
Switch circuit, 31, 32...PNP transistor, 33, 34...NPN transistor, 37,
38... Sliding resistance, 4... Main sensor, 5... Weighted addition circuit.

Claims

[Scope of Claims] 1. A circuit that performs temperature compensation on measurement signals obtained by measuring various physical quantities in accordance with the temperature of the measurement environment, the circuit comprising: temperature detection means for detecting the temperature of the measurement environment; , signal inverting means for inverting the polarity of the temperature detection signal obtained by the temperature detection means and outputting it as an inverted signal, each of which connects the temperature detection signal and its inverted signal via a predetermined resistor; two switching means whose conduction states are mutually inverted when the temperature detection signal is larger than the inversion signal and when the inversion signal is larger than the temperature detection signal; and a temperature compensation signal outputted via the predetermined resistor. A temperature compensation circuit comprising: an addition means for adding to the measurement signal.