DE2340158C2 - Circuit arrangement for remote measurement of resistances - Google Patents
Circuit arrangement for remote measurement of resistancesInfo
- Publication number
- DE2340158C2 DE2340158C2 DE19732340158 DE2340158A DE2340158C2 DE 2340158 C2 DE2340158 C2 DE 2340158C2 DE 19732340158 DE19732340158 DE 19732340158 DE 2340158 A DE2340158 A DE 2340158A DE 2340158 C2 DE2340158 C2 DE 2340158C2
- Authority
- DE
- Germany
- Prior art keywords
- resistor
- differential amplifier
- measuring
- conductor
- over
- 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
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
- G01K7/18—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer
- G01K7/20—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer in a specially-adapted circuit, e.g. bridge circuit
- G01K7/21—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer in a specially-adapted circuit, e.g. bridge circuit for modifying the output characteristic, e.g. linearising
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
- G01K1/02—Means for indicating or recording specially adapted for thermometers
- G01K1/024—Means for indicating or recording specially adapted for thermometers for remote indication
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Resistance Or Impedance (AREA)
- Measuring Temperature Or Quantity Of Heat (AREA)
- Arrangements For Transmission Of Measured Signals (AREA)
Description
2. Schaltungsanordnung nach Anspruch 1, da- Der am Meßort befindliche Meßwiderstand Rm, durch gekennzeichnet, daß die erste und die beispielsweise e;n Widerstandsthermometer ΡΓ100, zweite Stromquelle (Sl, S2) gleichartige, vom ist über eine Drcileiterschaltung L1, L2, L3 an die Differenzverstärker (Kl) parallel gesteuerte Tran- 35 eigentliche Meßschaltung 1 angeschlossen. Die Leisistoren sind, durch die gleiche Ströme (/) fließen, tungswiderstände der drei Leiter Ll, L 2 und L 3 und daß der Widerstand (R 2) am zweiten Ein- seien RjI, RjI und Rj3. 2. Circuit arrangement according to claim 1, that the measuring resistor Rm located at the measurement location, characterized in that the first and the e.g. connected to the differential amplifier (Kl) parallel controlled Tran 35 actual measuring circuit 1. The power resistors are, through which the same currents (/) flow, resistance of the three conductors Ll, L 2 and L 3 and that the resistor (R 2) at the second one are RjI, RjI and Rj3.
gang (22) des zweiten Differenzverstärkers (V2) In der eigentlichen Meßschaltung 1 ist der strom-output (22) of the second differential amplifier (V 2) In the actual measuring circuit 1, the current
den halben Wert des Fe*twiderstandes (Rf) auf- führende Ausgang eines ersten Differenzverstärkers weist. 40 Vl mit den Basen zweier gleichartiger Transistorenhas half the value of the Fe * twiderstandes (Rf) leading output of a first differential amplifier. 40 Vl with the bases of two transistors of the same type
verbunden, die als gesteuerte Stromquellen Sl undconnected, which as controlled power sources Sl and
S2 wirken. Aus der Stromquelle S1 wird über denS2 work. From the current source S1 is via the
Leiter L 2 ein Strom i geführt, welcher zum Teil über den zwischen den Leitern Ll und L 2 angeordnetenConductor L 2 conducts a current i , which is partly via the between the conductors Ll and L 2
Die Erfindung bezieht sich auf eine Schaltungsan- 45 Meßwiderstand Am und zum Teil über den Leiter L 3 Ordnung zur Fernmessung von Widerständen, bei der zurückfließt. Damit die Spannungsabfälle über die ein in Reihe mit einem Festwiderstand geschalteter Leitungswiderstände Rj 1 und Kj 3 gleich werden, ist Meßwiderstand aus einem ersten Differenzverstärker dafür zu sorgen, daß auf den Leitern L1 und L 3 jegespeist wird, an dessen einem Eingang eine Refe- weils ein Strom von der Größe i/2 fließt. Dazu ist in renzspannung und an dessen anderem Eingang der 50 dem den Leiter L 3 speisenden Zweig ein steuerbarer Spannungsabfall über den Festwiderstand als Rück- Widerstand TrI vorgesehen, der den Änderungen des führspannung liegt. Meßwiderstands Rm genau folgen soll. Das wird da-The invention relates to a circuit measuring resistor Am and in part via the conductor L 3 order for remote measurement of resistances in which there is a return flow. To ensure that the voltage drops across the line resistances Rj 1 and Kj 3 connected in series with a fixed resistor become the same, a measuring resistor from a first differential amplifier must be used to feed any conductors L1 and L 3 with a reference at one input a current of the size i / 2 flows. For this purpose, a controllable voltage drop across the fixed resistor as a return resistor TrI is provided in the reference voltage and at its other input of the branch feeding the conductor L 3, which is the changes in the lead voltage. Measuring resistor Rm should follow exactly. That will be
Eine derartige Schaltungsanordnung ist im Prinzip durch erreicht, daß die Verhältnisse im Speisezweig aus der DT-OS 2 158 269 bekannt. Die Verbindung des Meßwiderstands Rm in dem dritten Zweig nachdes Meßwiderstands, beispielsweise eines an einem 55 gebildet werden.Such a circuit arrangement is achieved in principle by the fact that the conditions in the feed branch are known from DT-OS 2,158,269. The connection of the measuring resistor Rm in the third branch after the measuring resistor, for example one on a 55, can be formed.
Meßort befindlichen Widerstandsthermometers mit Am Eingang 11 des ersten Differenzverstärkers Vl Resistance thermometer located at the measuring point at the input 11 of the first differential amplifier Vl
der an einem andern Ort befindlichen übrigen Meß- Hegt eine Spannung, die über einen Widerstand R1 schaltung geschieht dort über zwei Leiter. Hierbei abfällt, der in Reihe mit einem Potentiometer P1 von gehen die Leitungswiderstände der Zweileiterschal- einer Konstantstromquelle K gespeist wird. Am Eintung in die Messung ein, was sich bei größerer Ent- 60 gang 12 des Differenzverstärkers Vl liegt als Rückfernung zwischen Widerstand und Meßschaltung so- führspannung der Spannungsabfall über einen Festwie bei sich ändernden Umgebungseinflüssen, ins- widerstand Rf, der mit dem Meßwiderstand Am in besondere Temperatureinflüssen, nachteilig bemerk- Reihe liegt und demgemäß von dem gleichen Strom bar macht. durchflossen wird. Der gleiche Spannungsabfall überthe rest of the measurement located at a different location harbors a voltage that occurs via a resistor R 1 circuit there via two conductors. In this case, the line resistances of the two-wire circuit to a constant current source K are fed in series with a potentiometer P 1. On Eintung included in the measurement, which has a gear with greater decision 60 12 of the differential amplifier Vl is as Rückfernung between resistance and measuring circuit so-voltage drop recirculation voltage via a Festwie in changing environmental conditions, and in resistor Rf connected to the measuring resistor at the in special temperature influences, disadvantageously noticeable series and accordingly makes bar of the same stream. is traversed. The same voltage drop across
Es besteht demgemäß die Aufgabe, die bekannte 65 Rf Hegt auch am Eingang 21 eines zweiten Differenzen und für sich zur Linearisierung der Temperatur- Verstärkers V 2, an dessen anderem Eingang 22 die messung mittels Widerstandsthermometer ausgelegte über einen Widerstand R 2 abfallende Spannung liegt. Schaltungsanordnung so zu erweitern, daß die Ver- Der Widerstand R 2 w.rd aus der von der Ausgangs-There is accordingly the task of the well-known 65 Rf Hegt also at the input 21 of a second difference and for the linearization of the temperature amplifier V 2, at the other input 22 of the measurement by means of a resistance thermometer is located across a resistor R 2 dropping voltage. To expand the circuit arrangement so that the resistance R 2 w.rd from the output
größe des ersten Differenzverstärkefs Vl gesteuerten Stromquelle S2 gespeist, die ebenso wie die Stromquelle 51 einen Strom ι gleicher Stromstärke abgibt, die Ausgangsgröße des zweiten Differenzverstärkers V2 steuert den steuerbaren Widerstand TrI, der hier als Transistor ausgebildet ist. Wählt man den Widerstand R 2 halb so groß wie den Festwiderstand Rf, so wird der steuerbare Widerstand TrI so ausgesteuert, daß an den Widerständen Rf und R2 die gleichen Spannungen abfallen, d. h., die Ströme durch den Leiter 1 und den Leiter 3 sind gleich und betragen jeweils die Hälfte des über L 2 zugeführten Stroms f. Die dem sich nut der Temperatur ändernden Meßwiderstand Am entsprechende Meßspannung Um wird an dem mit einem Ende des Meßwiderstands Rm verbundenen Leiter L 3 und dem Potentiometer Pl abgegriffen, mit welchem der Meßbereichsanfang beliebig einstellbar ist.Size of the first differential amplifier Vl- controlled current source S2 fed, which, like the current source 51, emits a current ι of the same current strength, the output of the second differential amplifier V2 controls the controllable resistor TrI, which is designed here as a transistor. If the resistor R 2 is chosen to be half the size of the fixed resistor Rf, the controllable resistor TrI is controlled in such a way that the same voltages drop across the resistors Rf and R2 , that is, the currents through the conductor 1 and the conductor 3 are equal and are each half of the current f supplied via L 2. The measuring voltage Um corresponding to the measuring resistor Am, which changes with the temperature, is tapped at the conductor L 3 connected to one end of the measuring resistor Rm and the potentiometer Pl , with which the start of the measuring range can be set as desired .
Hierzu 1 Blatt Zeichnungen1 sheet of drawings
Claims (1)
quelle (S 2) gespeist ist, derart, daß die Ströme Zur Erläuterung der Erfindung ist in der Figur einInput (22) which is connected to a further resistor as. In this way, the voltage dropping with a small amount of circuitry (Ä2) and that the wall can be achieved that the line resistances resistance (R 2) from a likewise from the difference of the connecting lines of measuring resistor and The second current measuring circuit controlled by the reference amplifier ( V 1) does not influence the measurement result,
source (S 2) is fed in such a way that the currents To explain the invention is a in the figure
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19732340158 DE2340158C2 (en) | 1973-08-08 | 1973-08-08 | Circuit arrangement for remote measurement of resistances |
JP8861774A JPS50112068A (en) | 1973-08-08 | 1974-07-31 |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19732340158 DE2340158C2 (en) | 1973-08-08 | 1973-08-08 | Circuit arrangement for remote measurement of resistances |
Publications (2)
Publication Number | Publication Date |
---|---|
DE2340158B1 DE2340158B1 (en) | 1974-11-14 |
DE2340158C2 true DE2340158C2 (en) | 1975-07-10 |
Family
ID=5889209
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DE19732340158 Expired DE2340158C2 (en) | 1973-08-08 | 1973-08-08 | Circuit arrangement for remote measurement of resistances |
Country Status (2)
Country | Link |
---|---|
JP (1) | JPS50112068A (en) |
DE (1) | DE2340158C2 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0039751A1 (en) * | 1980-05-08 | 1981-11-18 | Imperial Chemical Industries Plc | Electrical resistance measurement |
DE3806058A1 (en) * | 1988-02-26 | 1989-09-07 | Philips Patentverwaltung | Measuring device for resistance measurement |
-
1973
- 1973-08-08 DE DE19732340158 patent/DE2340158C2/en not_active Expired
-
1974
- 1974-07-31 JP JP8861774A patent/JPS50112068A/ja active Pending
Also Published As
Publication number | Publication date |
---|---|
JPS50112068A (en) | 1975-09-03 |
DE2340158B1 (en) | 1974-11-14 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
E77 | Valid patent as to the heymanns-index 1977 | ||
EHJ | Ceased/non-payment of the annual fee |