SU901847A1 - Device for measuring temperature - Google Patents

Description

(54) DEVICE FOR MEASURING TEMPERATURE

The invention relates to temperature measurements using resistance thermometers with non-linear temperature characteristics, such as platinum. Temperature measuring devices are known that contain a transformer bridge whose arms are formed by two secondary windings of a voltage transformer, an exemplary resistor and a resistance thermocouple fll and 21. The disadvantage of these devices is the low measurement accuracy due to the nonlinear dependence of the output value on the measured temperature. The closest to the present invention is a temperature measuring device containing a transformer bridge, whose arms are formed by two secondary windings of a voltage transformer, a reference resistor, and an additional resistance thermometer, an adjustable secondary winding, and a balanced adjustment of the secondary windings of the main and additional currents transformers f3. The presence of two adjustable windings complicates the instrument's measuring circuit and reduces its manufacturability; in addition, an additional transformer introduces errors into the measurement results. A significant disadvantage of the known device is the complexity of its readjustment when using thermocouples of various types, caused by the need for multi-decade adjustment of the numbers of turns of transformer windings. The purpose of the invention is to improve the measurement accuracy and simplify the operation of the device. This goal is achieved by the fact that a temperature measuring device containing a transformer bridge, whose shoulders are formed by a TLD1-1I secondary windings of a voltage transformer, an exemplary resistor and a resistance thermocouple, a discrete level unit, one of which is connected to To the control input of the adjustable parameter switch, a code matching circuit, a pulse counter, three tenth frequency multipliers, a result counter, a counting pulse generator, and a counter are entered. The register, with the output of the discrete balancing unit connected to the inputs of the code matching circuit, the second inputs of which are connected to the information outputs of the pulse counter, and its output to the control input of the selector, the NSD of which is connected to the output of the counting pulse generator, and the output to the counting input the result counter and the input of one of the first and second decimal smart frequency estels, the output of the first multiplier is connected to the counting input of the counter-register associated with the information outputs with the control inputs of the second mind ozhitel, the output of which the third through a decimal frequency multiplier is connected to the counting input of counters .CHIK & pulses. the decimal frequency multiplier contains a software decade counter and a divider counter, the counting inputs of which are connected to the multiplier input, the outputs from the decades of counters are connected to the trigger setup inputs, the outputs of which are connected to the first inputs of the coincidence circuit, the second inputs of which are connected to counting ones the inputs of the decades, and the outputs to the inputs of the collecting circuit, the output of which is the output of the multiplier, the output of each decade of the counter-divider is connected to the recording input of the corresponding decade of the program counter and the input from the decade multiplying multiplier, and as a counter-divider of the first two multipliers is the counter of the result. FIG. i shows the proposed device, a structural electrical circuit; in fig. 2 - Decimal 4 frequency multiplier, structural electrical circuit. The device contains a transformer 1 with a primary winding 2 and secondary windings 3 and 4, one of which 4 is adjustable, an exemplary resistor 5, a thermal converter 6 resistance block 7 discrete equilibration, a circuit 8 matches the code, a counter 9 pulses, decimal multipliers 10-12 frequency , counter 13 of the result, the counter register 14, the selector 15 and the generator 16 counting pulses, the switch of the adjustable parameter of the bridge (not shown). The decimal frequency multiplier contains a software decade counter 17, consisting of decades 17-1,.,., 17-I, counter-divider 18 with decades 18-1,., 18-C, triggers 1U-1 ,. .., 19-11, schemes 20-1 ,. .., 20-h matches and collecting circuit 21. Decades of counter 18 are connected in series, the inputs of these decades are connected to the inputs of the decades of counter 17 and the first inputs of the matching circuits, the second inputs of which are connected to the outputs of flip-flops 19-1, ..., ly n. The outputs of the decades of both counters are connected to the setup inputs of the triggers, and the outputs of the decades of the counter fS are also connected to the recording inputs of the decades 17-1, ..., 17-ji. The outputs of the matching circuits 20-1, ..., 20-I are connected to the inputs of the collecting circuit 21, the output of which is the output of the multiplier. The device works as follows. The discrete balancing unit 7 balances the measuring bridge by adjusting the number of turns of the winding 4 of the transformer 1. The real equilibrium condition of the bridge is W RO and RO RO. YN bRoIR number of turns of windings where m., M 3 and 4i are the resistance of the reference resistor 5, the resistance of the thermal converter 6 o H0 The dependence of the resistance of platinum thermal converters on the temperature in describes the power of the polynomial. Therefore, the function (8) is also

901847

x

/ t

Claims (1)

V - the number of turns of the windings 3 and 4; K. - sample resistance th resistor 5; Cd - resistance thermocouple 6 £ ( ^{Ы- ίθ} The temperature dependence of the resistance of platinum. Transducers Θ is described by degrees polynomial. Therefore, the function £ (θ) is also 901847 Uzhhorod, Project 4,