JPH0124273B2 - - Google Patents
Info
- Publication number
- JPH0124273B2 JPH0124273B2 JP56205915A JP20591581A JPH0124273B2 JP H0124273 B2 JPH0124273 B2 JP H0124273B2 JP 56205915 A JP56205915 A JP 56205915A JP 20591581 A JP20591581 A JP 20591581A JP H0124273 B2 JPH0124273 B2 JP H0124273B2
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- circuit
- constant current
- resistance element
- variable resistance
- 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
- 230000005856 abnormality Effects 0.000 claims description 24
- 238000001514 detection method Methods 0.000 claims description 19
- 230000002159 abnormal effect Effects 0.000 claims description 11
- 230000007423 decrease Effects 0.000 claims description 4
- 238000000034 method Methods 0.000 description 24
- 238000010586 diagram Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 206010027339 Menstruation irregular Diseases 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/28—Testing of electronic circuits, e.g. by signal tracer
- G01R31/282—Testing of electronic circuits specially adapted for particular applications not provided for elsewhere
- G01R31/2829—Testing of circuits in sensor or actuator systems
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
- Testing Electric Properties And Detecting Electric Faults (AREA)
Description
【発明の詳細な説明】
本発明は、測定事象の変化に相応して抵抗値の
変化する可変抵抗素子の端子電圧を、デジタル的
に測定表示するとともに、上記可変抵抗素子の断
線異常をも検出する異常検出回路に関するもので
ある。Detailed Description of the Invention The present invention digitally measures and displays the terminal voltage of a variable resistance element whose resistance value changes in accordance with changes in measurement events, and also detects disconnection abnormalities in the variable resistance element. The present invention relates to an abnormality detection circuit.
従来の可変抵抗素子を用いた測定装置は第１図
に示したように構成されている。第１図におい
て、１は定電流回路、２は温度の変化に依存する
可変抵抗素子、３は電圧指示部であり、可変抵抗
素子２に定電流を流し、周囲の温度の変化に応じ
て変化する抵抗値の変化を可変抵抗素子２の両端
の電圧変化として取り出し、この電圧を電圧指示
部３で指示している。 A conventional measuring device using a variable resistance element is constructed as shown in FIG. In Figure 1, 1 is a constant current circuit, 2 is a variable resistance element that depends on changes in temperature, and 3 is a voltage indicator. The change in resistance value is taken out as a voltage change across the variable resistance element 2, and this voltage is indicated by the voltage indicator 3.
このように構成された従来の測定装置では、例
えば可変抵抗素子２にサーミスタを用いた場合、
周囲の温度が高くなるにつれて抵抗値が下がり、
また高温部では抵抗値の変化が少なくなるので、
単に電圧を指示する電圧指示部３では表示が見に
くく、更にこの装置ではデジタル表示をすること
ができないという欠点がある。また可変抵抗素子
２が何らかの原因で破断したような異常状態時に
も単にフルスケールを指示するだけにとどまり、
計測指示動作との差異が判別し得ず、異常状態の
まま放置されるという問題を有している。 In the conventional measuring device configured in this way, for example, when a thermistor is used as the variable resistance element 2,
As the surrounding temperature increases, the resistance value decreases,
In addition, the change in resistance value decreases in high temperature areas, so
The voltage indicator 3, which simply indicates the voltage, has a disadvantage in that the display is difficult to read, and furthermore, this device cannot provide digital display. In addition, even in an abnormal state such as when the variable resistance element 2 is broken for some reason, it simply indicates full scale.
There is a problem in that the difference from the measurement instruction operation cannot be determined and the abnormal state is left as it is.
本発明は、上記従来例の欠点を解消するために
定電流回路から可変抵抗素子に定電流を流し、こ
の可変抵抗素子の端子電圧と、一定の周期または
不定周期で上昇または下降する段階波形電圧を可
変電圧出力回路から出力して比較し、両電圧の大
小関係が逆転した時の可変電圧出力回路の出力電
圧に応じたデジタル表示をするとともに、可変抵
抗素子に破断等の異常が生じた場合、その抵抗値
の大幅変化を同様の比較動作で判定し、表示器に
て警告を与える検出回路の提供を目的とするもの
である。 In order to eliminate the drawbacks of the conventional example described above, the present invention allows a constant current to flow from a constant current circuit to a variable resistance element, and a terminal voltage of this variable resistance element and a step waveform voltage that rises or falls at a fixed period or an irregular period. is output from the variable voltage output circuit and compared, and a digital display is displayed according to the output voltage of the variable voltage output circuit when the magnitude relationship of both voltages is reversed, and if an abnormality such as breakage occurs in the variable resistance element. The object of the present invention is to provide a detection circuit that determines a large change in the resistance value by a similar comparison operation and issues a warning on a display.
以下、添付図面に基づいて本発明の実施例を詳
述する。 Embodiments of the present invention will be described in detail below based on the accompanying drawings.
第２図は、本発明の一実施例の検出回路図を示
したもので、４は比較回路５、トランジスタ６、
低抗７，８，９，１０からなるそれ自体周知の定
電流回路、１１は可変抵抗素子、１２は比較回
路、１３はマイクロコンピユータ、１４は駆動回
路、１５は表示回路であり、マイクロコンピユー
タ１３の出力端子Ａ、Ｂ、Ｃに直列抵抗１６，１
７，１８がそれぞれ接続され、また低抗１６，１
７，１８のそれぞれの間およびアースとの間に並
列抵抗１９，２０，２１が接続されて可変電圧出
力回路２２を構成し、抵抗１６，１９の接続点は
比較回路１２の反転入力端子に接続されている。
２３は定電流回路４におけるトランジスタ６のベ
ース・エミツタ間を短絡するトランジスタで、そ
のベースは抵抗２４を通してマイクロコンピユー
タ１３の出力端子Ｅに接続されている。２５は定
電流回路４と並列に接続された高抵抗値を有する
直列低抗で、定電流供給時における可変抵抗素子
１１の端子電圧にほとんど影響を与えず、かつ可
変抵抗素子１１の大幅な抵抗値変化を判定し得る
大きさに設定される。 FIG. 2 shows a detection circuit diagram of an embodiment of the present invention, in which reference numeral 4 indicates a comparison circuit 5, a transistor 6,
11 is a variable resistance element, 12 is a comparator circuit, 13 is a microcomputer, 14 is a drive circuit, 15 is a display circuit, and the microcomputer 13 Series resistors 16, 1 are connected to the output terminals A, B, and C of
7 and 18 are connected respectively, and low resistance 16 and 1
Parallel resistors 19, 20, and 21 are connected between each of resistors 7 and 18 and between the ground and constitute a variable voltage output circuit 22, and the connection point of resistors 16 and 19 is connected to the inverting input terminal of the comparator circuit 12. has been done.
A transistor 23 short-circuits the base and emitter of the transistor 6 in the constant current circuit 4, and its base is connected to the output terminal E of the microcomputer 13 through a resistor 24. 25 is a series low resistor with a high resistance value connected in parallel with the constant current circuit 4, which hardly affects the terminal voltage of the variable resistance element 11 when constant current is supplied, and which has a large resistance of the variable resistance element 11. It is set to a size that allows a value change to be determined.
このように構成された本実施例の検出装置で
は、定電流回路４から可変抵抗素子１１に一定電
流が流されると、この可変抵抗素子１１で発生し
た電圧が比較回路１２に入力される。このときマ
イクロコンピユータ１３の出力端子Ｅは通常検出
状態に対応して高出力を維持しており、したがつ
てトランジスタ２３もオフ状態となるため正常の
定電流供給動作がなされる。一方マイクロコンピ
ユータ１３の出力端子Ａ、Ｂ、Ｃには下記の表で
示したような電圧が順次出力される。すなわち、
端子Ａ、Ｂ、Ｃに（１、１、１）の出力電圧が出
された時は、端子Ｄに最大の電圧V1が発生し、
次に端子Ａ、Ｂ、Ｃに（１、１、０）の電圧が発
生した時には、次の電圧V2が発生するというよ
うに、最大電圧V1から０の電圧V8が、一定周期
または不定周期で繰り返し出力され、比較回路１
２に入力される。この比較回路１２では、可変抵
抗素子１１の端子電圧と、マイクロコンピユータ
１３および低抗１６〜２１からなる可変電圧出力
回路２２からの変化電圧とを比較し、変化電圧が
可変抵抗素子１１の端子電圧よりも小さくなり、
両電圧の大小関係が逆転した時に、すなわち、比
較回路１２の出力がそれまでの低出力から高出力
へ反転した時に、マイクロコンピユータ１３は、
この高出力を検出し、この時に端子Ａ、Ｂ、Ｃか
ら出力していた信号を駆動回路１４に出力する
と、駆動回路１４はこの信号の電圧に応じた信号
を出力し、表示回路１５では、この信号によつて
可変抵抗素子１１の端子電圧に応じたデジタル表
示がなされる。 In the detection device of this embodiment configured as described above, when a constant current is passed from the constant current circuit 4 to the variable resistance element 11, the voltage generated in the variable resistance element 11 is inputted to the comparison circuit 12. At this time, the output terminal E of the microcomputer 13 maintains a high output corresponding to the normal detection state, and therefore the transistor 23 is also turned off, so that a normal constant current supply operation is performed. On the other hand, voltages as shown in the table below are sequentially output to output terminals A, B, and C of the microcomputer 13. That is,
When output voltages (1, 1, 1) are output to terminals A, B, and C, the maximum voltage V 1 is generated at terminal D,
Next, when voltages (1, 1, 0) are generated at terminals A, B, and C, the next voltage V 2 is generated, and so on, the voltage V 8 from the maximum voltage V 1 to 0 is maintained at a fixed period or It is repeatedly output at irregular intervals, and the comparator circuit 1
2 is input. This comparison circuit 12 compares the terminal voltage of the variable resistance element 11 with the changing voltage from the variable voltage output circuit 22 consisting of the microcomputer 13 and the low resistance resistors 16 to 21, and compares the changing voltage with the terminal voltage of the variable resistance element 11. becomes smaller than
When the magnitude relationship between both voltages is reversed, that is, when the output of the comparator circuit 12 is reversed from a low output to a high output, the microcomputer 13
When this high output is detected and the signals output from terminals A, B, and C at this time are output to the drive circuit 14, the drive circuit 14 outputs a signal corresponding to the voltage of this signal, and the display circuit 15 outputs a signal corresponding to the voltage of this signal. This signal provides a digital display according to the terminal voltage of the variable resistance element 11.
＜表＞
Ａ Ｂ Ｃ
V1 １ １ １
V2 １ １ ０
V3 １ ０ １
V4 １ ０ ０
V5 ０ １ １
V6 ０ １ ０
V7 ０ ０ １
V8 ０ ０ ０
本実施例では、マイクロコンピユータおよび直
列・並列の抵抗からなる可変電圧出力回路２２か
ら段階的に減少する電圧を順次出力し、この出力
電圧と可変抵抗素子１１の端子電圧の大小関係を
比較し、可変電圧出力回路２２からの変化電圧が
可変抵抗素子１１の端子電圧よりも小さくなつた
時にその時出力した可変電圧回路２２からの出力
に応じたデジタル表示を行なうようにしたので、
可変抵抗素子１１の端子電圧が低くても、表示が
正確になるという利点がある。 <Table> A B C V 1 1 1 1 V 2 1 1 0 V 3 1 0 1 V 4 1 0 0 V 5 0 1 1 V 6 0 1 0 V 7 0 0 1 V 8 0 0 0 In this example , a variable voltage output circuit 22 consisting of a microcomputer and series/parallel resistors sequentially outputs a voltage that decreases step by step, and compares this output voltage with the terminal voltage of the variable resistance element 11 to generate a variable voltage output circuit. 22 becomes smaller than the terminal voltage of the variable resistance element 11, a digital display is made according to the output from the variable voltage circuit 22 that is output at that time.
There is an advantage that even if the terminal voltage of the variable resistance element 11 is low, the display can be accurate.
なお、更に表示を正確にするには、マイクロコ
ンピユータ１３の出力端子数を増やせばよい。た
とえば、出力端子をＡ、Ｂ、Ｃ、Ｄの４つにした
場合には、可変電圧出力回路２２の出力電圧が16
段階になり、より正確になる。 Note that in order to make the display even more accurate, the number of output terminals of the microcomputer 13 may be increased. For example, if there are four output terminals A, B, C, and D, the output voltage of the variable voltage output circuit 22 is 16
Gradually, it becomes more accurate.
ここで、可変電圧出力回路２２における最大の
出力電圧V1は、可変抵抗素子１１の常用変動範
囲数十Ωから数百Ωにおける最大の端子電圧を検
出し得る値に設定され、こうした範囲内で端子電
圧と変化電圧との比較動作による対応したデジタ
ル表示がなされることになる。 Here, the maximum output voltage V 1 in the variable voltage output circuit 22 is set to a value that can detect the maximum terminal voltage in the common fluctuation range of the variable resistance element 11 from several tens of Ω to several hundreds of Ω. A corresponding digital display is made by comparing the terminal voltage and the changing voltage.
以上のように、可変抵抗素子１１が上記常用範
囲で変化している通常動作時には、比較回路１２
の出力変化時における変化電圧に対応した表示プ
ロセスが実行されるが、いま可変抵抗素子１１の
抵抗値が可変電圧出力回路２２の変化電圧範囲を
はずれた場合、比較回路１２による反転動作がな
されないため、マイクロコンピユータ１３は異常
入力と判断して、出力端子Ｅを高出力から低出力
に反転する。このため、トランジスタ２３がオン
し、定電流回路４におけるトランジスタ６のベー
ス・エミツタ間を短絡して、可変抵抗素子１１へ
の定電流の供給を遮断する。これにより比較回路
１２の比較端子には、高抵抗値を有する低抗２５
との分圧比により決定される端子電圧が印加され
ることになるが、このときの変化電圧との比較動
作は、マイクロコンピユータ１３の出力端子Ｅが
高出力である通常の表示プロセスから、検出入力
の異常判定プロセスを実行するルーチンに移行す
る。すなわち、通常の検出動作において可変抵抗
素子１１の端子電圧が可変電圧出力回路２２から
の変化電圧範囲をはずれ、出力端子Ｅが低出力に
反転した時の異常判定プロセスでは、直列抵抗２
５との分圧レベルが変化電圧と比較され、その大
小関係がどの変化電圧点において逆転するかで実
行される。たとえば可変抵抗素子１１が温度検出
用のサーミスタで構成される場合、表示回路１５
の表示範囲に対応する常用検出範囲数十Ω〜数百
Ωに対し、極寒地において数十KΩに達すること
があり、こうした特殊状態と可変抵抗素子１１あ
るいは接続ラインの破断による異常状態とを判別
して確実に異常警告を与えるために、直列抵抗２
５を100KΩに設定し、可変抵抗素子１１との分
圧比が所定値を越えたときに断線異常と判定する
構成が具体例としてあげられる。つまり、可変抵
抗素子１１が破断したような場合、その抵抗値は
無限大になるため、直列抵抗２５との分圧比によ
る端子電圧があらかじめ設定した判定条件となる
変化電圧を越え、これにより異常状態として表示
回路１５における警告機能を作動させ、上述した
極寒地において可変抵抗素子１１が数十KΩに達
した場合には、やはり異常判定プロセスに移る
が、直列抵抗２５との分圧比による端子電圧が判
定条件となる変化電圧以下であるため正常状態と
判定され、単に最低の温度表示を与えるといつた
表示プロセスが実行されるよう構成することがで
きる。 As described above, during normal operation when the variable resistance element 11 is changing within the above-mentioned normal range, the comparator circuit 12
A display process corresponding to the changing voltage when the output changes is executed, but if the resistance value of the variable resistance element 11 is now out of the changing voltage range of the variable voltage output circuit 22, the comparator circuit 12 will not perform the inversion operation. Therefore, the microcomputer 13 determines that the input is abnormal and inverts the output terminal E from high output to low output. Therefore, the transistor 23 is turned on, short-circuiting the base and emitter of the transistor 6 in the constant current circuit 4, and cutting off the supply of constant current to the variable resistance element 11. As a result, the comparison terminal of the comparison circuit 12 has a low resistor 25 having a high resistance value.
A terminal voltage determined by the voltage division ratio between The process moves to a routine that executes the abnormality determination process. That is, in the abnormality determination process when the terminal voltage of the variable resistance element 11 deviates from the change voltage range from the variable voltage output circuit 22 in normal detection operation and the output terminal E is reversed to a low output, the series resistor 2
The divided voltage level of 5 is compared with the changing voltage, and the comparison is performed depending on at which changing voltage point the magnitude relationship is reversed. For example, if the variable resistance element 11 is composed of a thermistor for temperature detection, the display circuit 15
While the normal detection range corresponds to the display range of several tens of ohms to several hundred ohms, it can reach several tens of kilohms in extremely cold regions, and it is necessary to distinguish between these special conditions and abnormal conditions due to a break in the variable resistance element 11 or the connection line. In order to reliably give an abnormality warning, the series resistor 2
5 is set to 100KΩ, and when the voltage division ratio with the variable resistance element 11 exceeds a predetermined value, a disconnection abnormality is determined. In other words, if the variable resistance element 11 breaks, its resistance value becomes infinite, so the terminal voltage due to the voltage division ratio with the series resistor 25 exceeds the change voltage that is the preset judgment condition, and this causes an abnormal state. When the warning function in the display circuit 15 is activated and the variable resistance element 11 reaches several tens of kilohms in the above-mentioned extremely cold region, the process moves to an abnormality determination process, but the terminal voltage due to the voltage division ratio with the series resistor 25 is Since the change voltage is below the determination condition, it is determined to be in a normal state, and a display process such as simply providing the lowest temperature display can be executed.
したがつて、直列抵抗２５の値を任意に選定す
れば、可変抵抗素子１１の特性に応じた高精度の
デジタル表示が可能となる検出装置で、可変抵抗
素子１１の破断等の異常をも確実に検出でき、特
別の比較判定回路を付加することなく、常用範囲
以外の特殊条件下における抵抗値変化との判別も
可能な極めて信頼性の高い警告動作を得られるも
のである。 Therefore, if the value of the series resistor 25 is arbitrarily selected, the detection device can provide a highly accurate digital display according to the characteristics of the variable resistance element 11, and it is possible to detect abnormalities such as breakage of the variable resistance element 11 without fail. It is possible to obtain an extremely reliable warning operation that can be detected from a change in resistance value under special conditions outside the normal range without adding a special comparison/judgment circuit.
また、上記実施例においては、可変抵抗素子１
１の端子電圧が可変電圧出力回路２２から出力さ
れる常用範囲の変化電圧をはずれたとき、異常判
定プロセスを実行する構成をとつたが、変化電圧
の任意高位レベルでの逆転動作で実行させてもよ
く、いずれの場合も常用範囲における表示プロセ
ス実行時にはマイクロコンピユータ１３の出力端
子Ｅを高出力として、トランジスタ２３をオフ状
態に維持し、端子電圧が常用範囲をはずれるかあ
るいは限界レベルに達したときに出力端子Ｅを低
出力に反転してトランジスタ２３をオンするとと
もに、異常判定プロセスを実行して可変抵抗素子
１１の異常を検出する方法であり、直列抵抗２５
との分圧比による判定動作は以下に示す監視方式
でも可能である。 Further, in the above embodiment, the variable resistance element 1
1 is configured to execute the abnormality determination process when the voltage at the terminal 1 deviates from the normal range of changing voltage outputted from the variable voltage output circuit 22, but it is not possible to carry out the process by reversing the changing voltage at an arbitrary high level. In either case, when the display process is executed in the normal range, the output terminal E of the microcomputer 13 is set to high output and the transistor 23 is kept in an off state, and when the terminal voltage goes out of the normal range or reaches a limit level, This method detects an abnormality in the variable resistance element 11 by inverting the output terminal E to a low output and turning on the transistor 23, and at the same time executing an abnormality determination process.
The determination operation based on the partial pressure ratio can also be performed using the monitoring method described below.
すなわち、可変抵抗素子１１の端子電圧と可変
電圧出力回路２２の変化電圧とを比較し、その大
小関係が逆転する変化電圧点に応じた表示プロセ
スを実行する中で、任意時点に出力端子Ｅを低出
力に反転して定電流供給を遮断し、直列抵抗２５
との分圧比による端子電圧の判定動作を所定周期
で実行する方式である。たとえば、可変電圧出力
回路２２の変化電圧が最高V1から最低V8まで変
化する判定プロセスを１サイクルとし、５サイク
ルに１度の割合で出力端子Ｅを低出力に反転し、
このときの直列低抗２５との分圧比による端子電
圧を異常判定プロセスにより比較判定する構成を
とるとすれば、常用範囲においては可変抵抗素子
１１の端子電圧と可変電圧出力回路２２の変化電
圧との大小関係の逆転時に応じたデジタル表示が
なされ、マイクロコンピユータ１３の出力端子Ｅ
が低出力に反転する異常判定プロセスでは直列抵
抗２５との分圧比による端子電圧が正常レベルと
判定されて現測定表示値を保持する表示動作が繰
り返えされる。また、可変抵抗素子１１の抵抗値
が常用範囲を大きくはずれた場合、可変抵抗素子
１１の端子電圧は可変電圧出力回路２２の変化電
圧を越えることになるが、このときにも表示プロ
セスは繰り返し実行されており、表示回路１５に
は表示範囲における最小表示単位が表示される。
こうした表示サイクルの中でマイクロコンピユー
タ１３の出力端子Ｅを低出力に反転する異常判定
プロセスが所定周期で実行されるが、このとき直
列抵抗２５との分圧比による端子電圧が判定条件
となる変化電圧よりも低い場合、すなわち極寒地
において数十KΩに達する特殊条件下では正常範
囲と判定して最小表示単位の表示を保持し、端子
電圧が判定条件となる変化電圧よりも高い場合に
は可変抵抗素子１１の断線等異常状態として警告
機能を作動させることになる。 That is, while comparing the terminal voltage of the variable resistance element 11 and the changing voltage of the variable voltage output circuit 22 and executing a display process according to the changing voltage point at which the magnitude relationship is reversed, the output terminal E is connected at an arbitrary time. The output is reversed to low, the constant current supply is cut off, and the series resistor 25
This method executes the terminal voltage determination operation at a predetermined period based on the voltage division ratio. For example, one cycle is a determination process in which the voltage of the variable voltage output circuit 22 changes from a maximum of V 1 to a minimum of V 8 , and the output terminal E is inverted to a low output once every five cycles.
If a configuration is adopted in which the terminal voltage based on the voltage division ratio with the series low resistor 25 is compared and judged by the abnormality judgment process, in the normal use range, the terminal voltage of the variable resistance element 11 and the changing voltage of the variable voltage output circuit 22 are A digital display is made according to the reversal of the magnitude relationship of the output terminal E of the microcomputer 13.
In the abnormality determination process in which the voltage is inverted to a low output, the terminal voltage based on the voltage division ratio with the series resistor 25 is determined to be at a normal level, and the display operation of holding the current measured display value is repeated. In addition, if the resistance value of the variable resistance element 11 greatly deviates from the normal range, the terminal voltage of the variable resistance element 11 will exceed the changing voltage of the variable voltage output circuit 22, but in this case, the display process is repeatedly executed. The display circuit 15 displays the minimum display unit in the display range.
During these display cycles, an abnormality determination process in which the output terminal E of the microcomputer 13 is inverted to a low output is executed at a predetermined cycle. Under special conditions where the resistance reaches several tens of kilohms in extremely cold regions, the terminal voltage is determined to be within the normal range and the display is maintained at the minimum display unit.If the terminal voltage is higher than the changing voltage that is the judgment condition, the variable resistance A warning function is activated as an abnormal state such as a disconnection of the element 11.
以上の監視方式においても、定電流回路４と接
続した直列抵抗２５による異常判定動作は同様で
あり、最初に説明した表示プロセスから異常判定
プロセスに検出条件で移行する方式とは単にその
判定時点が相違するだけで、何らその異常検出効
果を低下させるものではない。 In the above monitoring method, the abnormality determination operation by the series resistor 25 connected to the constant current circuit 4 is the same, and the method of transitioning from the display process to the abnormality determination process based on the detection conditions described at the beginning simply means that the determination point is Just being different does not reduce the anomaly detection effect in any way.
このように、本発明は測定事象に応じた抵抗値
変化を呈する可変抵抗素子に定電流を供給して、
その両端電圧の変化を可変電圧出力回路の変化電
圧と比較し、その大小関係が逆転したときの変化
電圧に対応する表示を行なうとともに、定電流回
路と並列にして可変抵抗素子と直列接続される抵
抗値の大なる抵抗を設け、可変抵抗素子の異常変
化時に定電流を遮断し、直列抵抗との分圧比によ
る端子電圧を所定の判定条件となる変化電圧と比
較し、その大小関係により可変抵抗素子の開放異
常を検知するよう構成したため、極めて精度のよ
いデジタル表示を行なうとともに、可変抵抗素子
の常用範囲を越える低抗値変化が特殊条件下にお
ける変動可能範囲での出力かあるいは可変抵抗素
子の開放異常かを確実に検出することができ、極
めて安全性に秀れた表示効果の高い検出装置を提
供し得るものである。 In this way, the present invention supplies a constant current to a variable resistance element that exhibits a resistance value change according to a measurement event,
The change in voltage at both ends is compared with the changing voltage of the variable voltage output circuit, and when the magnitude relationship is reversed, a display corresponding to the changing voltage is displayed, and it is connected in parallel with the constant current circuit and in series with the variable resistance element. A resistor with a large resistance value is installed to cut off the constant current when the variable resistance element changes abnormally, and the terminal voltage based on the voltage division ratio with the series resistor is compared with the changing voltage that is a predetermined judgment condition. Since it is configured to detect an open circuit abnormality in the element, it provides an extremely accurate digital display, and also indicates that a low resistance value change that exceeds the normal range of the variable resistance element is due to the output within the variable range under special conditions or the variable resistance element's output. It is possible to provide a detection device that can reliably detect whether there is an open abnormality, is extremely safe, and has a high display effect.
第１図は、従来の測定回路の回路図、第２図は
本発明に係る検出回路の一実施例を示す回路構成
図である。
４……定電流回路、１１……可変抵抗素子、１
２……比較回路、１３……マイクロコンピユー
タ、１４……駆動回路、１５……表示回路、１６
〜２１……可変電圧出力回路を形成する抵抗、２
２……可変電圧出力回路、２３……定電流遮断用
トランジスタ、２５……異常検出用の直列抵抗。
FIG. 1 is a circuit diagram of a conventional measuring circuit, and FIG. 2 is a circuit configuration diagram showing an embodiment of a detection circuit according to the present invention. 4... Constant current circuit, 11... Variable resistance element, 1
2... Comparison circuit, 13... Microcomputer, 14... Drive circuit, 15... Display circuit, 16
~21...Resistor forming a variable voltage output circuit, 2
2... Variable voltage output circuit, 23... Constant current cutoff transistor, 25... Series resistor for abnormality detection.
Claims (1)
して上記可変抵抗素子から得られた検出電圧と、
可変電圧出力回路から出力され、段階的に上昇ま
たは下降する変化電圧とを比較し、上記検出電圧
と変化電圧の大小関係が逆転した時に変化電圧に
応じた記録または表示を行うとともに、上記定電
流回路と並列に上記可変抵抗素子の常用変動範囲
よりもはるかに大なる値を有する直列抵抗を接続
し、かつ上記定電流回路からの一定電流を遮断す
るスイツチング回路を設け、上記一定電流を遮断
する条件下で上記直列抵抗との分圧比による検出
電圧を異常入力として変化電圧と比較し、所定時
期での大小関係により可変抵抗素子が異常状態に
あることを判定するよう構成したことを特徴とす
る測定装置における異常検出回路。 ２ 上記可変抵抗素子の端子から得られる検出電
圧が可変電圧出力回路の変化電圧による比較範囲
をはずれるかあるいは限界レベルに達した時、上
記スイツチング回路を作動して定電流回路からの
一定電流を遮断し、上記直列抵抗との分圧比によ
る検出電圧を異常入力として比較判定することを
特徴とする特許請求の範囲第１項記載の測定装置
における異常検出回路。 ３ 上記定電流回路からの一定電流を遮断するス
イツチング回路を所定周期で作動させ、このとき
の上記直列抵抗との分圧比による検出電圧を異常
入力として比較判定するとともに、この異常入力
が正常範囲にあるときには直前の表示出力を保持
することを特徴とする特許請求の範囲第１項記載
の測定装置における異常検出回路。[Claims] 1. A detection voltage obtained from the variable resistance element by passing a constant current through the variable resistance element from a constant current circuit;
The variable voltage that is output from the variable voltage output circuit and increases or decreases step by step is compared, and when the magnitude relationship between the detected voltage and the variable voltage is reversed, recording or display is performed according to the variable voltage, and the constant current is A series resistor having a value much larger than the normal fluctuation range of the variable resistance element is connected in parallel with the circuit, and a switching circuit is provided to cut off the constant current from the constant current circuit to cut off the constant current. The variable resistance element is characterized in that the voltage detected by the voltage division ratio with the series resistor is compared with the changing voltage as an abnormal input under certain conditions, and it is determined that the variable resistance element is in an abnormal state based on the magnitude relationship at a predetermined time. Abnormality detection circuit in measuring equipment. 2 When the detected voltage obtained from the terminal of the variable resistance element falls outside the comparison range based on the changing voltage of the variable voltage output circuit or reaches a limit level, the switching circuit is activated to cut off the constant current from the constant current circuit. 2. An abnormality detection circuit in a measuring device according to claim 1, wherein a detected voltage based on a voltage division ratio with said series resistor is used as an abnormal input for comparison and determination. 3 The switching circuit that cuts off the constant current from the constant current circuit is operated at a predetermined period, and the detected voltage at this time based on the voltage division ratio with the series resistor is compared and determined as an abnormal input, and the abnormal input is within the normal range. 2. An abnormality detection circuit in a measuring device according to claim 1, wherein the abnormality detection circuit in a measuring device according to claim 1, is characterized in that the immediately preceding display output is held at certain times.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56205915A JPS58106474A (en) | 1981-12-18 | 1981-12-18 | Fault detecting circuit for measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56205915A JPS58106474A (en) | 1981-12-18 | 1981-12-18 | Fault detecting circuit for measuring device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58106474A JPS58106474A (en) | 1983-06-24 |
| JPH0124273B2 true JPH0124273B2 (en) | 1989-05-10 |
Family
ID=16514849
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56205915A Granted JPS58106474A (en) | 1981-12-18 | 1981-12-18 | Fault detecting circuit for measuring device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58106474A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0726995B2 (en) * | 1987-08-10 | 1995-03-29 | 株式会社東芝 | Sensor disconnection detection circuit |
| CN105403790A (en) * | 2015-12-09 | 2016-03-16 | 珠海格力电器股份有限公司 | series arc fault detection circuit and method |
| JP6289587B1 (en) * | 2016-11-08 | 2018-03-07 | 三菱電機株式会社 | Power converter |
| CN108196184B (en) * | 2018-01-25 | 2023-06-20 | 昆明理工大学 | XL series boost chip detection device and method |
-
1981
- 1981-12-18 JP JP56205915A patent/JPS58106474A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58106474A (en) | 1983-06-24 |
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