EP0479009A1 - Temperature sensor - Google Patents
Temperature sensor Download PDFInfo
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- EP0479009A1 EP0479009A1 EP91115573A EP91115573A EP0479009A1 EP 0479009 A1 EP0479009 A1 EP 0479009A1 EP 91115573 A EP91115573 A EP 91115573A EP 91115573 A EP91115573 A EP 91115573A EP 0479009 A1 EP0479009 A1 EP 0479009A1
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- resistor
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- circuit
- temperature
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- 230000001419 dependent effect Effects 0.000 claims abstract description 15
- 239000003990 capacitor Substances 0.000 claims description 15
- 238000011156 evaluation Methods 0.000 claims description 15
- 229910004670 OPV1 Inorganic materials 0.000 claims description 8
- 238000005259 measurement Methods 0.000 claims description 4
- 238000001514 detection method Methods 0.000 description 4
- 230000003321 amplification Effects 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 229910004667 OPV2 Inorganic materials 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 230000036561 sun exposure Effects 0.000 description 1
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B17/00—Fire alarms; Alarms responsive to explosion
- G08B17/12—Actuation by presence of radiation or particles, e.g. of infrared radiation or of ions
Definitions
- the invention relates to a heat sensor with a resistor arrangement containing at least one temperature-dependent resistor and connected to a voltage supply, and with a first amplifier circuit which is connected on the input side to the resistor arrangement and on the output side to a first measuring and evaluation circuit.
- the object of the invention is therefore to enable the detailed, rapid detection of the room temperature without foregoing known and proven properties and without significantly increasing the effort compared to conventional heat detectors.
- a second, frequency response-compensated amplifier circuit is provided, which is connected on the input side to the resistor arrangement via a high-pass circuit and on the output side to a second measurement and evaluation circuit.
- the resistor arrangement is designed as a voltage divider, a resistor being connected in series with the temperature-dependent resistor and the first amplifier circuit having its first input at the connection point of this resistor with the temperature-dependent resistor and with its second input at the connection point of the temperature-dependent resistor the negative pole of the power supply is connected.
- the first and the second amplifier circuit are each formed with a negative feedback operational amplifier, these preferably being designed as non-inverting amplifiers.
- the output of the operational amplifier is connected to its inverting input via a resistor and the inverting input is connected to the negative pole of the voltage supply via a capacitor connected in parallel with a capacitor.
- the high-pass circuit is preferably formed with a capacitor connecting the center tap of the voltage divider with the first input of the second amplifier circuit and a resistor connecting the first input of the second amplifier circuit with the negative pole of the supply voltage.
- An embodiment of the heat sensor according to the invention which is particularly advantageous because of its low expenditure is provided in that only one frequency response-compensated amplifier circuit is provided, which is connected on the input side to the resistor arrangement and on the output side to a measuring and evaluation circuit.
- the amplifier circuit can be formed with a negative feedback operational amplifier, which is preferably designed as a non-inverting amplifier.
- the output of the operational amplifier is connected via a resistor to its inverting input and the inverting input via the parallel connection of a resistor to the series circuit comprising a resistor and a capacitor to the negative pole of the voltage supply.
- the temperature-dependent resistor is expediently formed using a thermistor.
- a voltage divider with the terminals is formed from a resistor R1 and a thermistor HL + Ub and -Ub connected to a power supply.
- the power supply is located in a control center, not shown, to which the heat sensor is connected via a primary signal line, also not shown.
- the first input E11 is connected to the connection point of the thermistor HL with the resistor R1 and the second input E12 of an amplifier circuit V1 is connected to the connection point of the thermistor HL with the terminal -Ub of the voltage supply.
- the amplifier circuit V1 consists of an operational amplifier OPV1, the inverting input E1- of which is connected on the one hand via a resistor R3 to its output Av1 and on the other hand forms the second input E12 of the amplifier circuit V1 via a resistor R2.
- the non-inverting input E1 + of the operational amplifier OPV1 forms the first input E11 of the amplifier circuit V1.
- the OPV1 operational amplifier is also connected to the two terminals + Ub and -Ub of the power supply.
- the output Av1 of the operational amplifier OPV1 simultaneously forms the output of the amplifier circuit V1 and is connected to the input of a first measuring and evaluation circuit M1 + A 1 .
- the output of this measuring and evaluation circuit M1 + A is connected to a terminal MA1.
- the first input E21 of an amplifier circuit V2 is also connected to the connection point of the thermistor HL with the resistor R1 via a capacitor C1.
- This first input E21 is also connected via a resistor R4 to the connection point of the thermistor HL to the terminal -Ub, to which the second input E22 of the amplifier circuit V2 is also connected.
- the amplifier circuit V2 is constructed similarly to the amplifier circuit V1, the operational amplifier OPV2 corresponding to the operational amplifier OPV1, the resistor R6 to the resistor R3 and the parallel connection of a resistor R5 with a capacitor C2 to the resistor R2.
- the output Av2 of the operational amplifier OPV2 is connected to the input of a second measuring and evaluation circuit M2 + A2, the output of which is connected to a terminal MA2.
- a transmission device not shown.
- the voltage drop across the thermistor HL is temperature-dependent, the amplitude of this voltage decreasing with increasing frequency.
- the amplification of the amplifier circuit V1 is set via the resistors R2 and R3 in such a way that very slow changes in the voltage can be recognized and processed by the first measuring and evaluation circuit M1 + A, the signals with frequencies between 5 Hz and However, 20 Hz are not sufficiently amplified to be able to be evaluated. Therefore, the second amplifier circuit V2 is provided, which is preceded by a high-pass circuit consisting of the capacitor C1 and the resistor R4.
- This high-pass circuit sifts out the slow signal components, so that the gain of V2 can be set via the resistors R5 and R6 so that the second measuring and evaluation circuit M2 + A2 e.g. the intensity of the signal components in the desired frequency range between 5 Hz and 20 Hz is recorded and evaluated.
- the measurement values can be evaluated in M1 + A1 as well as in M2 + A2 by one or more threshold switches, or an analog value proportional to the measured amplitude can also be generated and transmitted to the control center.
- the capacitor C2 provided in the amplifier circuit V2 ensures an increase in the gain with increasing frequency, so that the frequency response of the thermistor HL is partially compensated for by the amplifier circuit V2.
- FIG. 2 An embodiment of the invention which is particularly advantageous because of its low expenditure is shown in FIG. 2.
- the voltage on the thermistor HL is amplified by the amplifier circuit V and fed to the measuring and evaluation circuit M + A.
- the structure of the amplifier circuit V corresponds to the amplifier circuit V1 from FIG. 1, the operational amplifier OPV1 through an operational amplifier OPV, the resistor R3 through a resistor R8 and the resistor R2 through the parallel connection of a resistor R9 with the series circuit of a capacitor C3 with a resistor R7 to be replaced.
- the amplification of the amplifier circuit V is set by the resistors R9 and R8, the amplification increasing with increasing frequency due to the capacitor C3, and thus the frequency response of the thermistor HL is compensated.
- the gain R7 can only increase the gain up to a certain frequency, so that the frequency response of the thermistor HL can only be compensated for up to a limited fluctuation rate, e.g. up to a limit frequency of 20 Hz.
- Resistor R7 can be inserted in series with capacitor C2 in FIG. 1 with the same effect.
- a corresponding complete low-pass filter can then be dispensed with in the measuring and evaluation circuit M2 + A2.
- the same options as described for FIG. 1 apply to the mode of operation of the measuring and evaluation circuit M + A and for the output to the terminal MA or for signal transmission. It is particularly simple and expedient to query the measured value so often that the desired rate of fluctuation can be detected, e.g. 40 times per second and the measured values obtained in this way are transferred to the control center for further processing. These measured values can be used individually, i.e. in the example, one every fortieth of a second, as well as combined into longer telegrams, e.g. 10 measured values are transmitted every quarter of a second.
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Abstract
Description
Die Erfindung betrifft einen Wärmesensor mit einer mindestens einen temperaturabhängigen Widerstand enthaltenden, an eine Spannungsversorgung angeschlossenen Widerstandsanordnung, und mit einer ersten Verstärkerschaltung, die eingangsseitig mit der Widerstandsanordnung und ausgangsseitig mit einer ersten Meß- und Auswerteschaltung verbunden ist.The invention relates to a heat sensor with a resistor arrangement containing at least one temperature-dependent resistor and connected to a voltage supply, and with a first amplifier circuit which is connected on the input side to the resistor arrangement and on the output side to a first measuring and evaluation circuit.
Für die automatische Brandentdeckung ist die durch ein Feuer entstehende Wärme ein naheliegendes Kriterium. Jedoch führen auch viele andere Wärmequellen als ein Schadenfeuer zu Temperaturerhöhungen, wie z.B. Sonneneinstrahlung, Heizungen, diverse Arbeitsprozesse und vieles andere mehr, so daß es nicht möglich ist, allein aufgrund einer kleinen Temperaturerhöhung auf ein Schadenfeuer zu schließen und die Feuerwehr zu alarmieren. Dies gilt besonders, wenn man bereits sehr kleine Feuer entdecken, bzw. ein Schadenfeuer bereits im Frühstadium detektieren will. Zu diesem Zweck ist es hilfreich, die Temperaturänderungen detaillierter zu betrachten und zu bewerten, wobei es sich als besonders nützlich herausgestellt hat, rasche und kleine Temperaturschwankungen zu erkennen. Dem steht entgegen, daß rasche Änderungen der Raumtemperatur nur mit sehr aufwendigen Meßeinrichtungen, nicht aber mit den in der Brandschutztechnik gebräuchlichen "Wärmemeldern" ermittelt werden können.The heat generated by a fire is an obvious criterion for automatic fire detection. However, many heat sources other than damage fire also lead to temperature increases, e.g. Sun exposure, heating, various work processes and much more, so that it is not possible to conclude that a fire is due to a small increase in temperature and to alert the fire department. This is especially true if you already discover very small fires, or if you want to detect a damage fire at an early stage. For this purpose, it is helpful to look at and evaluate temperature changes in more detail, and it has proven particularly useful to detect rapid and small temperature fluctuations. This is opposed to the fact that rapid changes in the room temperature can only be determined with very complex measuring devices, but not with the "heat detectors" used in fire protection technology.
Es ist üblich, eine automatische Feuermeldung mittels sogenannter "Wärme-Maximalmelder" erst dann auszulösen, wenn die Raumtemperatur wesentlich über der unter normalen Umständen erreichbaren Raumtemperatur von z.B. 40 °C liegt. Es ist weiterhin bekannt, mittels sogenannter "Wärme-Differentialmelder" lineare Temperaturanstiege von z.B. mehr als 10 K/min zur Alarmgabe zu nutzen. Beide Melder reagieren daher erst bei relativ großen Bränden. Zur Früherkennung von Bränden müssen daher andere Brandentdeckungsverfahren, z.B. mittels Rauchmeldern, herangezogen werden.It is common to only trigger an automatic fire alarm using so-called "maximum heat detectors" when the room temperature is significantly higher than the room temperature that can be reached under normal circumstances, e.g. 40 ° C. It is also known, by means of so-called "heat differential detectors", linear temperature increases of e.g. to use more than 10 K / min for the alarm. Both detectors therefore only react to relatively large fires. For the early detection of fires, other fire detection methods, e.g. using smoke detectors.
Aufgabe der Erfindung ist es daher, die detaillierte, rasche Erfassung der Raumtemperatur ohne Verzicht auf bekannte und bewährte Eigenschaften und ohne wesentliche Erhöhung des Aufwandes gegenüber gebräuchlichen Wärmemeldern zu ermöglichen.The object of the invention is therefore to enable the detailed, rapid detection of the room temperature without foregoing known and proven properties and without significantly increasing the effort compared to conventional heat detectors.
Die Aufgabe wird dadurch gelöst, daß eine zweite, frequenzgangkompensierte Verstärkerschaltung, die eingangsseitig über eine Hochpaßschaltung mit der Widerstandsanordnung und ausgangsseitig mit einer zweiten Meß- und Auswerteschaltung verbunden ist, vorgesehen ist.The object is achieved in that a second, frequency response-compensated amplifier circuit is provided, which is connected on the input side to the resistor arrangement via a high-pass circuit and on the output side to a second measurement and evaluation circuit.
In einer möglichen Ausführungsform des Erfindungsgegenstandes ist die Widerstandsanordnung als Spannungsteiler ausgebildet, wobei ein Widerstand in Serie zum temperaturabhängigen Widerstand geschaltet ist und die erste Verstärkerschaltung mit ihrem ersten Eingang am Verbindungspunkt dieses Widerstands mit dem temperaturabhängigen Widerstand und mit ihrem zweiten Eingang am Verbindungspunkt des temperaturabhängigen Widerstand mit dem Minuspol der Spannungsversorgung angeschlossen ist.In a possible embodiment of the subject of the invention, the resistor arrangement is designed as a voltage divider, a resistor being connected in series with the temperature-dependent resistor and the first amplifier circuit having its first input at the connection point of this resistor with the temperature-dependent resistor and with its second input at the connection point of the temperature-dependent resistor the negative pole of the power supply is connected.
In weiterer Ausgestaltung der Erfindung sind die erste und die zweite Verstärkerschaltung jeweils mit einem gegengekoppelten Operationsverstärker gebildet, wobei diese vorzugsweise als nicht-invertierende Verstärker ausgebildet sind.In a further embodiment of the invention, the first and the second amplifier circuit are each formed with a negative feedback operational amplifier, these preferably being designed as non-inverting amplifiers.
In einer weiteren Ausführungsform ist in der zweiten Verstärkerschaltung der Ausgang des Operationsverstärkers über einen Widerstand mit seinem invertierenden Eingang und der invertierende Eingang über die Parallelschaltung eines Widerstands mit einem Kondensator mit dem Minuspol der Spannungsversorgung verbunden.In a further embodiment, in the second amplifier circuit, the output of the operational amplifier is connected to its inverting input via a resistor and the inverting input is connected to the negative pole of the voltage supply via a capacitor connected in parallel with a capacitor.
Die Hochpaßschaltung ist vorzugsweise mit einem den Mittelabgriff des Spannungsteilers mit dem ersten Eingang der zweiten Verstärkerschaltung verbindenden Kondensator und einem den ersten Eingang der zweiten Verstärkerschaltung mit dem Minuspol der Versorgungsspannung verbindenden Widerstand gebildet.The high-pass circuit is preferably formed with a capacitor connecting the center tap of the voltage divider with the first input of the second amplifier circuit and a resistor connecting the first input of the second amplifier circuit with the negative pole of the supply voltage.
Eine wegen ihres geringen Aufwandes besonders vorteilhafte Ausführungsform des erfindungsgemäßen Wärmesensors ist dadurch gegeben, daß nur eine frequenzgangkompensierte Verstärkerschaltung, die eingangsseitig mit der Widerstandsanordnung und ausgangsseitig mit einer Meß- und Auswerteschaltung verbunden ist, vorgesehen ist.An embodiment of the heat sensor according to the invention which is particularly advantageous because of its low expenditure is provided in that only one frequency response-compensated amplifier circuit is provided, which is connected on the input side to the resistor arrangement and on the output side to a measuring and evaluation circuit.
Die Verstärkerschaltung kann dabei mit einem gegengekoppelten Operationsverstärker gebildet werden, wobei dieser vorzugsweise als nicht-invertierender Verstärker ausgebildet ist.The amplifier circuit can be formed with a negative feedback operational amplifier, which is preferably designed as a non-inverting amplifier.
In einer vorteilhaften Ausführungsform dieses Wärmesensors ist der Ausgang des Operationsverstärkers über einen Widerstand mit seinem invertierenden Eingang und der invertierende Eingang über die Parallelschaltung eines Widerstands mit der Serienschaltung aus einem Widerstand und einem Kondensator mit dem Minuspol der Spannungsversorgung verbunden.In an advantageous embodiment of this heat sensor, the output of the operational amplifier is connected via a resistor to its inverting input and the inverting input via the parallel connection of a resistor to the series circuit comprising a resistor and a capacitor to the negative pole of the voltage supply.
In allen Ausführungsformen wird der temperaturabhängige Widerstand zweckmäßigerweise mit einem Heißleiter gebildet.In all embodiments, the temperature-dependent resistor is expediently formed using a thermistor.
Die Erfindung soll anhand von Ausführungsbeispielen mit Hilfe von Figuren näher beschrieben werden. Es zeigen dabei
- Fig. 1 eine mögliche Ausführungsform des Erfindungsgegenstandes,
- Fig. 2 eine weitere mögliche Ausführungsform des Erfindungsgegenstandes.
- 1 shows a possible embodiment of the subject matter of the invention,
- Fig. 2 shows another possible embodiment of the subject matter of the invention.
Beim in Fig.1 dargestellten Wärmesensor ist ein aus einem Widerstand R1 und einem Heißleiter HL gebildeter Spannungsteiler mit den Klemmen + Ub und -Ub einer Spannungsversorgung verbunden. Die Spannungsversorgung befindet sich dabei in einer nicht dargestellten Zentrale, mit der der Wärmesensor über eine ebenfalls nicht dargestellte Meldeprimärleitung verbunden ist.In the case of the heat sensor shown in FIG. 1, a voltage divider with the terminals is formed from a resistor R1 and a thermistor HL + Ub and -Ub connected to a power supply. The power supply is located in a control center, not shown, to which the heat sensor is connected via a primary signal line, also not shown.
An den Verbindungspunkt des Heißleiters HL mit dem Widerstand R1 ist der erste Eingang E11 und an den Verbindungspunkt des Heißleiters HL mit der Klemme -Ub der Spannungsversorgung ist der zweite Eingang E12 einer Verstärkerschaltung V1 angeschlossen.The first input E11 is connected to the connection point of the thermistor HL with the resistor R1 and the second input E12 of an amplifier circuit V1 is connected to the connection point of the thermistor HL with the terminal -Ub of the voltage supply.
Die Verstärkerschaltung V1 besteht dabei aus einem Operationsverstärker OPV1, dessen invertierender Eingang E1- einerseits über einen Widerstand R3 mit seinem Ausgang Av1 verbunden ist und andererseits über einen Widerstand R2 den zweiten Eingang E12 der Verstärkerschaltung V1 bildet. Der nicht-invertierende Eingang E1 + des Operationsverstärkers OPV1 bildet den ersten Eingang E11 der Verstärkerschaltung V1. Der Operationsverstärker OPV1 ist außerdem an die beiden Klemmen + Ub und -Ub der Spannungsversorgung angeschlossen. Der Ausgang Av1 des Operationsverstärkers OPV1 bildet gleichzeitig den Ausgang der Verstärkerschaltung V1 und ist mit dem Eingang einer ersten Meß- und Auswerteschaltung M1 +A1 verbunden. Der Ausgang dieser Meß- und Auswerteschaltung M1 + A ist mit einer Klemme MA1 verbunden. Es ist allerdings auch möglich, den Ausgang der Meß- und Auswerteschaltung M1 +A1 mittels einer nicht dargestellten Übertragungseinrichtung an die Klemmen + Ub und -Ub anzuschließen.The amplifier circuit V1 consists of an operational amplifier OPV1, the inverting input E1- of which is connected on the one hand via a resistor R3 to its output Av1 and on the other hand forms the second input E12 of the amplifier circuit V1 via a resistor R2. The non-inverting input E1 + of the operational amplifier OPV1 forms the first input E11 of the amplifier circuit V1. The OPV1 operational amplifier is also connected to the two terminals + Ub and -Ub of the power supply. The output Av1 of the operational amplifier OPV1 simultaneously forms the output of the amplifier circuit V1 and is connected to the input of a first measuring and evaluation circuit M1 + A 1 . The output of this measuring and evaluation circuit M1 + A is connected to a terminal MA1. However, it is also possible to connect the output of the measuring and evaluation circuit M1 + A 1 to the terminals + Ub and -Ub by means of a transmission device, not shown.
An den Verbindungspunkt des Heißleiters HL mit dem Widerstand R1 ist auch der erste Eingang E21 einer Verstärkerschaltung V2 über einen Kondensator C1 angeschlossen. Dieser erste Eingang E21 ist außerdem über einen Widerstand R4 mit dem Verbindungspunkt des Heißleiters HL mit der Klemme -Ub verbunden, an der auch der zweite Eingang E22 der Verstärkerschaltung V2 angeschlossen ist. Die Verstärkerschaltung V2 ist ähnlich aufgebaut wie die Verstärkerschaltung V1, wobei der Operationsverstärker OPV2 dem Operationsverstärker OPV1, der Widerstand R6 dem Widerstand R3 und die Parallelschaltung eines Widerstands R5 mit einem Kondensator C2 dem Widerstand R2 entspricht. Der Ausgang Av2 des Operationsverstärkers OPV2 ist mit dem Eingang einer zweiten Meß- und Auswerteschaltung M2+A2 verbunden, derer Ausgang an eine Klemme MA2 angeschlossen ist. Auch hier ist es möglich, den Ausgang über eine nicht dargestellte Übertragungseinrichtung an die Klemmen + Ub und -Ub anzuschließen.The first input E21 of an amplifier circuit V2 is also connected to the connection point of the thermistor HL with the resistor R1 via a capacitor C1. This first input E21 is also connected via a resistor R4 to the connection point of the thermistor HL to the terminal -Ub, to which the second input E22 of the amplifier circuit V2 is also connected. The amplifier circuit V2 is constructed similarly to the amplifier circuit V1, the operational amplifier OPV2 corresponding to the operational amplifier OPV1, the resistor R6 to the resistor R3 and the parallel connection of a resistor R5 with a capacitor C2 to the resistor R2. The output Av2 of the operational amplifier OPV2 is connected to the input of a second measuring and evaluation circuit M2 + A2, the output of which is connected to a terminal MA2. Here, too, it is possible to connect the output to terminals + Ub and -Ub via a transmission device, not shown.
Die am Heißleiter HL abfallende Spannung ist temperaturabhängig, wobei die Amplitude dieser Spannung mit zunehmender Frequenz abnimmt. Die Verstärkung der Verstärkerschaltung V1 ist über die Widerstände R2 und R3 so eingestellt, daß sehr langsame Änderungen der Spannung von der ersten Meß- und Auswerteschaltung M1 + A erkannt und verarbeitet werden können, die für einen entstehenden Brand charakteristischen Signale mit Frequenzen zwischen 5 Hz und 20 Hz jedoch nicht genügend verstärkt sind, um ausgewertet werden zu können. Deshalb ist die zweite Verstärkerschaltung V2 vorgesehen, der eine aus dem Kondensator C1 und dem Widerstand R4 bestehende Hochpaßschaltung vorgeschaltet ist. Diese Hochpaßschaltung siebt die langsamen Signalanteile aus, so daß die Verstärkung von V2 über die Widerstände R5 und R6 so eingestellt werden kann, daß die zweite Meß- und Auswerteschaltung M2+A2 z.B. die Intensität der Signalanteile im gewünschten Frequenzbereich zwischen 5 Hz und 20 Hz erfaßt und auswertet. Die Auswertung der Meßwerte kann dabei sowohl in M1 +A1 als auch in M2+A2 durch einen oder auch mehrere Schwellwertschalter erfolgen oder es kann aber auch ein der gemessenen Amplitude proportionaler Analogwert erzeugt und der Zentrale übermittelt werden. Der in der Verstärkerschaltung V2 vorgesehene Kondensator C2 sorgt für eine Zunahme der Verstärkung mit zunehmender Frequenz, so daß der Frequenzgang des Heißleiters HL durch die Verstärkerschaltung V2 teilweise kompensiert wird.The voltage drop across the thermistor HL is temperature-dependent, the amplitude of this voltage decreasing with increasing frequency. The amplification of the amplifier circuit V1 is set via the resistors R2 and R3 in such a way that very slow changes in the voltage can be recognized and processed by the first measuring and evaluation circuit M1 + A, the signals with frequencies between 5 Hz and However, 20 Hz are not sufficiently amplified to be able to be evaluated. Therefore, the second amplifier circuit V2 is provided, which is preceded by a high-pass circuit consisting of the capacitor C1 and the resistor R4. This high-pass circuit sifts out the slow signal components, so that the gain of V2 can be set via the resistors R5 and R6 so that the second measuring and evaluation circuit M2 + A2 e.g. the intensity of the signal components in the desired frequency range between 5 Hz and 20 Hz is recorded and evaluated. The measurement values can be evaluated in M1 + A1 as well as in M2 + A2 by one or more threshold switches, or an analog value proportional to the measured amplitude can also be generated and transmitted to the control center. The capacitor C2 provided in the amplifier circuit V2 ensures an increase in the gain with increasing frequency, so that the frequency response of the thermistor HL is partially compensated for by the amplifier circuit V2.
Eine wegen ihren geringen Aufwandes besonders vorteilhafte Ausführung der Erfindung zeigt Fig. 2. Die Spannung am Heißleiter HL wird von der Verstärkerschaltung V verstärkt und der Meß-und Auswerteschaltung M+A zugeführt. Die Verstärkerschaltung V entspricht in ihrem Aufbau der Verstärkerschaltung V1 aus Fig. 1, wobei der Operationsverstärker OPV1 durch einen Operationsverstärker OPV, der Widerstand R3 durch einen Widerstand R8 und der Widerstand R2 durch die Parallelschaltung eines Widerstandes R9 mit der Serienschaltung eines Kondensator C3 mit einem Widerstand R7 ersetzt werden. Die Verstärkung der Verstärkerschaltung V wird durch die Widerstände R9 und R8 eingestellt, wobei wegen des Kondensators C3 die Verstärkung mit zunehmender Frequenz zunimmt, und somit der Frequenzgang des Heißleiters HL kompensiert wird. Durch den Widerstand R7 kann die Verstärkungszunahme jedoch nur bis zu einer bestimmten Frequenz erfolgen, wodurch die Kompensation des Frequenzganges des Heißleiters HL nur bis zu einer begrenzten Schwankungsgeschwindigkeit, z.B. bis zu einer Grenzfrequenz von 20 Hz, wirksam ist. Der Widerstand R7 kann mit der gleichen Wirkung in Serie zum Kondensator C2 in Fig. 1 eingefügt werden. Es kann dann auf einen entsprechenden kompletten Tiefpaß in der Meß-und Auswerteschaltung M2+A2 verzichtet werden.An embodiment of the invention which is particularly advantageous because of its low expenditure is shown in FIG. 2. The voltage on the thermistor HL is amplified by the amplifier circuit V and fed to the measuring and evaluation circuit M + A. The structure of the amplifier circuit V corresponds to the amplifier circuit V1 from FIG. 1, the operational amplifier OPV1 through an operational amplifier OPV, the resistor R3 through a resistor R8 and the resistor R2 through the parallel connection of a resistor R9 with the series circuit of a capacitor C3 with a resistor R7 to be replaced. The amplification of the amplifier circuit V is set by the resistors R9 and R8, the amplification increasing with increasing frequency due to the capacitor C3, and thus the frequency response of the thermistor HL is compensated. However, the gain R7 can only increase the gain up to a certain frequency, so that the frequency response of the thermistor HL can only be compensated for up to a limited fluctuation rate, e.g. up to a limit frequency of 20 Hz. Resistor R7 can be inserted in series with capacitor C2 in FIG. 1 with the same effect. A corresponding complete low-pass filter can then be dispensed with in the measuring and evaluation circuit M2 + A2.
Für die Arbeitsweise der Meß- und Auswerteschaltung M+A und für die Ausgabe an die Klemme MA, bzw. für die Signalweiterleitung gelten die gleichen Möglichkeiten wie zu der Fig.1 beschrieben. Besonders einfach und zweckmäßig ist es, den Meßwert so häufig abzufragen, daß die gewünschte Schwankungsgeschwindigkeit erfaßt werden kann, z.B. 40 mal pro Sekunde und die so gewonnenen Meßwerte zur weiteren Bearbeitung in die Zentrale zu übertragen. Dabei können diese Meßwerte sowohl einzeln, d.h. im Beispiel, je einer jede vierzigstel Sekunde, als auch zu längeren Telegrammen zusammengefaßt, also z.B. je 10 Meßwerte jede Viertel Sekunde, übertragen werden.The same options as described for FIG. 1 apply to the mode of operation of the measuring and evaluation circuit M + A and for the output to the terminal MA or for signal transmission. It is particularly simple and expedient to query the measured value so often that the desired rate of fluctuation can be detected, e.g. 40 times per second and the measured values obtained in this way are transferred to the control center for further processing. These measured values can be used individually, i.e. in the example, one every fortieth of a second, as well as combined into longer telegrams, e.g. 10 measured values are transmitted every quarter of a second.
Claims (10)
dadurch gekennzeichnet,
daß die Widerstandsanordnung (R1,HL) als Spannungsteiler ausgebildet ist, wobei ein Widerstand (R1) in Serie zum temperaturabhängigen Widerstand (HL) geschaltet ist und die erste Verstärkerschaltung (V1) mit ihrem ersten Eingang (E11) am Verbindungspunkt dieses Widerstands (R1) mit dem temperaturabhängigen Widerstand (HL) und mit ihrem zweiten Eingang (E12) am Verbindungspunkt des temperaturabhängigen Widerstands (R1) mit dem Minuspol (-Ub) der Spannungsversorgung angeschlossen ist.2. Heat sensor according to claim 1,
characterized,
that the resistor arrangement (R1, HL) is designed as a voltage divider, a resistor (R1) being connected in series with the temperature-dependent resistor (HL) and the first amplifier circuit (V1) having its first input (E11) at the connection point of this resistor (R1) with the temperature-dependent resistor (HL) and with its second input (E12) at the connection point of the temperature-dependent resistor (R1) with the negative pole (-Ub) of the voltage supply.
dadurch gekennzeichnet,
daß die erste und die zweite Verstärkerschaltung (V1 ,V2) jeweils mit einem gegengekoppelten Operationsverstärker (OPV1,OPV2) gebildet sind.3. Heat sensor according to one of claims 1 or 2,
characterized,
that the first and the second amplifier circuit (V1, V2) are each formed with a negative feedback operational amplifier (OPV1, OPV2).
dadurch gekennzeichnet,
daß die gegengekoppelten Operationsverstärker (OPV1,OPV2) als nicht-invertierende Verstärker ausgebildet sind.4. Heat sensor according to claim 3,
characterized,
that the negative feedback operational amplifiers (OPV1, OPV2) are designed as non-inverting amplifiers.
dadurch gekennzeichnet,
daß in der zweiten Verstärkerschaltung (V2) der Ausgang (Av2) des Operationsverstärkers (OPV2) über einen Widerstand (R6) mit seinem invertierenden Eingang (E2-) und der invertierende Eingang (E2-) über die Parallelschaltung eines Widerstands (R5) mit einem Kondensator (C2) mit dem Minuspol (-Ub) der Spannungsversorgung verbunden ist.5. Heat sensor according to claim 4,
characterized,
that in the second amplifier circuit (V2) the output (Av2) of the operational amplifier (OPV2) via a resistor (R6) with its inverting input (E2-) and the inverting input (E2-) via the parallel connection of a resistor (R5) with one Capacitor (C2) is connected to the negative pole (-Ub) of the power supply.
dadurch gekennzeichnet,
daß die Hochpaßschaltung mit einem den Mittelabgriff des Spannungsteilers (R1,HL) mit dem ersten Eingang (E21) der zweiten Verstärkerschaltung (V2) verbindenden Kondensator (C1) und einem den ersten Eingang (E21) der zweiten Verstärkerschaltung (V2) mit dem Minuspol (-Ub) der Versorgungsspannung verbindenden Widerstand (R4) gebildet ist.6. Heat sensor according to one of claims 2 to 5,
characterized,
that the high-pass circuit has a capacitor (C1) connecting the center tap of the voltage divider (R1, HL) to the first input (E21) of the second amplifier circuit (V2) and a capacitor (C1) to the first input (E21) of the second amplifier circuit (V2) to the negative pole ( -Ub) of the supply voltage connecting resistor (R4) is formed.
dadurch gekennzeichnet,
daß die Widerstandsanordnung als Spannungsteiler ausgebildet ist, wobei ein Widerstand (R1) in Serie zum temperaturabhängigen Widerstand (HL) geschaltet ist und die Verstärkerschaltung (V) mit ihrem ersten Eingang (E1) am Verbindungspunkt dieses Widerstands (R1) mit dem temperaturabhängigen Widerstand (HL) und mit ihrem zweiten Eingang (E2) am Verbindungspunkt des temperaturabhängigen Widerstands (R1) mit dem Minuspol (-Ub) der Spannungsversorgung angeschlossen ist.8. A heat sensor according to claim 7,
characterized,
that the resistor arrangement is designed as a voltage divider, a resistor (R1) being connected in series with the temperature-dependent resistor (HL) and the amplifier circuit (V) having its first input (E1) at the connection point of this resistor (R1) with the temperature-dependent resistor (HL ) and with its second input (E2) at the connection point of the temperature-dependent resistor (R1) with the negative pole (-Ub) of the power supply.
dadurch gekennzeichnet, daß die Verstärkerschaltung (V) mit einem gegengekoppelten Operationsverstärker (OPV), gebildet ist.9. Heat sensor according to claim 7 or 8,
characterized in that the amplifier circuit (V) is formed with a negative feedback operational amplifier (OPV).
dadurch gekennzeichnet,
daß der Ausgang (Av) des Operationsverstärkers (OPV) über einen Widerstand (R8) mit seinem invertierenden Eingang (E-) und der invertierende Eingang (E-) über die Parallelschaltung eines Widerstandes (R9) mit der Serienschaltung aus einem Widerstand (R7) und einem Kondensator (C3) mit dem Minuspol (-Ub) der Spannungsversorgung verbunden ist.10. Heat sensor according to one of claims 8 or 9,
characterized,
that the output (Av) of the operational amplifier (OPV) via a resistor (R8) with its inverting input (E-) and the inverting input (E-) via the parallel connection of a resistor (R9) with the series circuit comprising a resistor (R7) and a capacitor (C3) is connected to the negative pole (-Ub) of the voltage supply.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4031621 | 1990-10-05 | ||
| DE4031621 | 1990-10-05 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0479009A1 true EP0479009A1 (en) | 1992-04-08 |
| EP0479009B1 EP0479009B1 (en) | 1996-11-27 |
Family
ID=6415696
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP91115573A Expired - Lifetime EP0479009B1 (en) | 1990-10-05 | 1991-09-13 | Temperature sensor |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0479009B1 (en) |
| AT (1) | ATE145745T1 (en) |
| DE (1) | DE59108378D1 (en) |
| ES (1) | ES2094177T3 (en) |
| GR (1) | GR3021795T3 (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2911540A (en) * | 1955-02-14 | 1959-11-03 | Gen Controls Co | Flame detection system |
| DE1960218A1 (en) * | 1969-12-01 | 1971-06-03 | Rainer Portscht | Temperature radiation detector for automatic fire detection or flame monitoring |
| CH519761A (en) * | 1971-03-04 | 1972-02-29 | Cerberus Ag | Flame detector |
| DE2631454A1 (en) * | 1976-07-13 | 1978-01-19 | Preussag Ag Feuerschutz | Flame detector for fire alarm system - uses photocell and demodulator to provide flicker signal to evaluation circuit which supplies alarm signal |
| DE2852971A1 (en) * | 1978-12-07 | 1980-06-26 | Preussag Ag Feuerschutz | Fire alarm responding to flame radiation and individual sparks - is esp. for pipelines and chimneys and compensates for day-night radiation variations |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2001764B (en) * | 1977-07-27 | 1982-03-03 | Coal Ind | Temperature measurement system |
-
1991
- 1991-09-13 AT AT91115573T patent/ATE145745T1/en not_active IP Right Cessation
- 1991-09-13 EP EP91115573A patent/EP0479009B1/en not_active Expired - Lifetime
- 1991-09-13 ES ES91115573T patent/ES2094177T3/en not_active Expired - Lifetime
- 1991-09-13 DE DE59108378T patent/DE59108378D1/en not_active Expired - Fee Related
-
1996
- 1996-11-28 GR GR960402965T patent/GR3021795T3/en unknown
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2911540A (en) * | 1955-02-14 | 1959-11-03 | Gen Controls Co | Flame detection system |
| DE1960218A1 (en) * | 1969-12-01 | 1971-06-03 | Rainer Portscht | Temperature radiation detector for automatic fire detection or flame monitoring |
| CH519761A (en) * | 1971-03-04 | 1972-02-29 | Cerberus Ag | Flame detector |
| DE2631454A1 (en) * | 1976-07-13 | 1978-01-19 | Preussag Ag Feuerschutz | Flame detector for fire alarm system - uses photocell and demodulator to provide flicker signal to evaluation circuit which supplies alarm signal |
| DE2852971A1 (en) * | 1978-12-07 | 1980-06-26 | Preussag Ag Feuerschutz | Fire alarm responding to flame radiation and individual sparks - is esp. for pipelines and chimneys and compensates for day-night radiation variations |
Non-Patent Citations (1)
| Title |
|---|
| RADIO FERNSEHEN ELEKTRONIK. Bd. 26, Nr. 6, 1976, BERLIN DD Seiten 207 - 208; UNKNOWN: 'OPTOELEKTRONISCHE FLAMMENUBERWACHUNG UND FEUERSCHUTZSCHALTUNG' * |
Also Published As
| Publication number | Publication date |
|---|---|
| ES2094177T3 (en) | 1997-01-16 |
| DE59108378D1 (en) | 1997-01-09 |
| EP0479009B1 (en) | 1996-11-27 |
| ATE145745T1 (en) | 1996-12-15 |
| GR3021795T3 (en) | 1997-02-28 |
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