SU1613878A1 - Device for measuring temperature - Google Patents

Abstract

The invention relates to a technique of temperature measurements and allows to increase the speed of the device by reducing the time spent on the formation of the measurement result. Temperature to frequency converter 1 generates pulses, the repetition period of which is inversely proportional to temperature. Frequency divider 5 and trigger 6 form from a periodic pulse sequence of converter 1 a signal whose duration is equal to the duration of the signal period of converter 1, during which counter 2 counts the pulses from the output of function generator 4. Digital indicator 3 displays the result of counting, which is proportional to the measured temperature. Shaper pulse reset 7 synchronizes the operation of the elements of the device. 1 hp f-ly, 4 ill.

Description

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The invention relates to temperature measurements and can be used in monitoring and control systems.

The purpose of the invention is to increase the speed of the device.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 - time diagrams of his work; in fig. 3 - structural diagram of the functional generator; in fig. 4 shows a structural circuit for converting temperature to frequency.

The device for measuring temperature contains a temperature-to-frequency converter 1, a counter 2, a digital indicator 3, a function generator 4, a frequency divider 5, a trigger 6, and a reset pulse generator 7.

The functional generator 4 (FIG. 3) comprises a reference frequency generator 8 and a first divider 9 with a variable division factor (DCPD) included in the ring, a pulse counter 10 and a second DPDD 11, the first input of the second DPD 11 connected to the output of the reference frequency generator 8 The second input of the second PDDK 11, the reset input of the counter 10 and the second input of the first PDCD 9 are interconnected and are the input 12 of the function generator 4, and its output 13 is the output of the first PDKD 9. At the output of the function generator 4, pulses are generated frequency followed which is proportional to 1 / t, where t - current time.

The temperature converter 1 in frequency (FIG. 4) contains a semiconductor (diode) temperature sensor 14, a current generator 15, a reference voltage source 16, an integrator 17, a switch 18, an additional switch 19, a voltage divider 20 and a comparator 21 .

The device works as follows.

At given times ti, t2, 13 at the output of the generator 7 of the reset pulses, signals are generated which determine the start of the temperature measurement process. These signals (diagram U2 in Fig. 2) are fed to the R inputs of the reset of the frequency divider 5, the trigger 6, the counter 2 and the functional generator 4, bringing them to zero states. Temperature to frequency converter 1 generates pulses (Us), the repetition period T of which is inversely proportional to sensor temperature 0

K temperature T that, where K - coefficient

proportionality. The frequency divider 5 and the trigger 6 are formed from a periodic sequence of pulses from the signal Us,

the duration of which is equal to the duration of the period of the signal from the output of the temperature to the frequency U5. The signal Us is fed to the input V of the counting counter 2, to the counting input From which pulses Ui are output from the output of the function generator, the frequency of which is proportional to 1 / g. With appropriate calibration, the number N of pulses accumulated in the counter during the measurement cycle Ue corresponds to temperature in degrees Celsius and indicated by a digital indicator 3. In order to get the maximum speed, the reset pulses U2 from the output of the driver 7 pulses are formed by the falling edge of the signal Us from the output of the trigger 6, m, e. after forming the measurement interval.

Functional generator (FG) 4 works as follows. The impulses Uz (Fig. 2) arrive at the input 12 Ф 4 from the output of the former 7 impulse pulses, each of which resets cnr 4 to its initial state and restarts it. In the initial state, the division ratio of each PDCD is minimal, and the pulse counter is in a single state. The first pulse from the output of the reference frequency generator 8 is fed through the second and first PDCD 9 and 11 to the counting input C of the counter 10 pulses. With the arrival of each pulse from the output of the first PDCD 9 to the input C of the pulse counter 10, the code value of the number in it changes by one, and the division ratio of the first and second PDCD 9 and 11 increases by 1/64, as a result of which the FG 4 produces a frequency a signal varying by the 1 / t law.

The temperature to frequency converter operates as follows.

The current from the current generator 15 produces a voltage drop across the diode temperature sensor 14, the value of which decreases with increasing temperature linearly. This voltage is applied to the input of the integrator 17. With the open keys 18 and 19 open, the voltage at the output of the integrator 17 increases until it coincides with the voltage applied to the first input of the comparator 21. At the time of coincidence of the voltages at the inputs of the comparator 21, it generates a short pulse opening key 20 through which the discharge of the capacitor of the integrator occurs. After closing the key 20, the process is periodically repeated, with the result that pulses from are formed at the output of the integrator 17. frequency

Claims (2)

repetitions of which are proportional to the temperature of the temperature sensor. Claims 1. A device for measuring temperature, comprising a temperature to frequency converter, a counter, the output of which is connected to the input of a digital indicator, trigger, characterized in that. that, in order to increase the speed of the device, a functional generator, a shaper of reset pulses and a frequency divider, the input of which is connected to the output of the temperature to frequency converter, are introduced into it, and the output is connected to the trigger input, the output of which is connected to the control input the reset pulse generator and the control input of the counter, the counting input of which is connected to the output of the function generator, while the output of the reset pulse generator is connected to the installation inputs g / l L III I iiniiiiiii 11 I Us ff | temperature to frequency converter, frequency divider, trigger, counter and function generator. 2. The device according to claim 1, characterized in that the functional generator comprises a reference frequency generator, a pulse counter and two frequency dividers with variable division ratio, the control inputs of which are connected to the output of the pulse counter, the installation input of which is connected to the installation input of the functional the generator and the installation inputs of the frequency dividers with a variable division factor, and the counting input is connected to the output of the function generator and the output of the first frequency divider with a variable factor division, the input of which is connected to the output of the reference frequency generator through a second frequency divider with a variable division factor. Fig.Z