SU1362959A1 - Device for measuring temperature - Google Patents

Abstract

This invention relates to a measurement technique. The purpose of the invention is to increase the accuracy and accuracy of the objects and simplify the design of the device. When the temperature deviates from the voltage, the imbalance arises, which is subtracted from the voltage developed on the winding 9. Change the voltage on the winding 4, change the voltage on the winding 9 until the latter is equal to the voltage at the midpoint of the divider from a resistor (measure) 5 and a thermometer 6, which is fixed by means of an equilibrium detector 10. The total measurement error will be determined. Voltage drift at the midpoint of the divider from resistor (measure) 5 and thermometer 6 at a temperature equal to zero, due to the temperature difference at which resistor (measure) 5 and thermometer 6 are located, and due to temperature instability. measure. 1 hp f-ly, 1 ill. 7 hl-U 00 O) N3 SO ate with

Description

The invention relates to a measurement technique and can be used to measure temperature, in particular in conductometry, in determining the salinity of seawater.

The aim of the invention is to increase the measurement accuracy and simplify the design of the device.

The drawing shows the electrical circuit of the device.

The device contains a voltage generator 1, a first transformer 2 with a primary winding 3 connected to a generator and a secondary adjustable winding 4, an exemplary resistor 5 and a resistance thermometer 6 connected in series, a second transformer 7 with a primary 8 and a secondary 9 windings , an equilibrium detector 10, a linearizing resistor 11, the first transformer 2 being equipped with a second 12 and a third 13 secondary windings

To increase noise immunity

winding devices 9 and 13 are shielded. The shield 14 is grounded at the connection side of the equilibrium detector 10, since its input voltage at the equilibrium point is zero. With such grounding, the voltage difference between the screen and the central core is zero at all points of windings 9 and 13, and also the communication lines between them, i.e. Equipotential protection is provided. Ultimately, this allows reducing the level of interference at the input of the equilibrium detector 10, broadening the dynamic range, increasing the number of divider bits (winding 4) and thereby reducing the error from discreteness.

The device works as follows.

The voltage of the generator through the windings 3 and 12 is applied to the divider, formed by series-connected exemplary resistor (measure) 5 and a resistance thermometer 6 at the midpoint of which voltage arises

.,., m p Rto ()

 and"

mj Rp + Rtod + e t)

where Uj is the voltage at the output of generator 1;

m., m is the number of turns of the windings 3 and 12, respectively;

R - exemplary resistance

resistor 5;

 - resistance of the thermometer 6 when

с - temperature coefficient

resistance of thermometer 6 material; t is the temperature. The winding 13 has a voltage

and

15

 Sho

In this case, the number of turns m.

the skein 13 is chosen such that U is equal at t 0, i.e.

Rtp

.R ;; R

Thus, in the zero position of the movable contact of the adjustable coil 4 and t O, the measuring circuit is in equilibrium.

When the temperature deviates from OC, an imbalance voltage arises, which is subtracted from the voltage developed on the winding 9. Change the voltage on the winding 4, thereby changing the voltage on the winding 9 until the latter is equal to the voltage the midpoint of the divider from the resistor 5 and the thermometer 6, which is fixed with the help of the detector 10 equilibrium.

The resulting non-linearity of reference is due to —the fact that the current of the divider I decreases with increasing temperature.

Ut I R i / 1 + o (t);

tf

m-ij uo

Ifl

 m ()

eliminated with a linearizing resistor 11 with resistance R / by introducing additional current

T 2. - R / m

where the number of turns of the winding 4,

With atom resistance R of resistor 11 is chosen so that Uj is linearly dependent on temperature.

The total error in temperature measurement will also be determined by the voltage drift at the midpoint of de313

a resistor (measure) 5 and a thermometer 6 at a temperature equal to zero due to the temperature difference at which the resistor (measure) 5 and the resistance thermometer 6 are located and due to temperature dependence

the bility of the measure R. If an exemplary resistor-measure 5 is placed in the same test medium as the thermometer. 6 resistance this error will almost be equal to zero. This changes the slope of the transformation. However, taking into account that the temperature coefficients of resistor 5 and thermometer 6 differ by three orders of magnitude, the change in slope will be 0.1% and is easily compensated during the tuning step.

Claims (2)

1. A device for measuring temperature, comprising a generator, a first transformer with a primary winding connected to a generator, and a secondary adjustable winding, a series-connected exemplary resistor and resistance thermometer, a second transformer with a primary and secondary windings, and an equilibrium detector, characterized in that , in order to improve the measurement accuracy and simplify the design of the device, linearizing Editor Y. Sereda Compiled by V. Golubev Tehred L. Serdyukova Corr Podpi 6390/28 Circulation 776 VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Design, 4; a resistor, and the first transformer is provided with a second and third secondary windings, with the secondary regulated winding of the first transformer connected to the primary winding of the second transformer, the linearizing resistor is connected between the movable contact of the adjustable winding and the common the point of the model resistor and the resistance thermometer, the second secondary winding of the first transformer is connected to a series of series-connected sample resistor and a resistance thermometer included in this circuit with its current terminals, and one of the two inputs of the equilibrium detector is connected through the series-connected secondary winding the second transformer and the third secondary winding of the first transformer to one of the potential terminals of the resistance thermometer, the other potential terminal of which is connected directly with the second input of the equilibrium detector. 2. The device according to claim 1, about tl and - that the secondary the winding of the second transformer and the third secondary winding of the first transformer are made and interconnected by a shielded wire, the shield of which is grounded on the input side equilibrium detector. Proofreader S. Cherni Subscription