SU1377607A1 - Electronic thermometer - Google Patents

Abstract

The invention relates to instrumentation. The purpose of the invention is to simplify the design of the thermometer and increase the information content of the visual display of the measured temperature and its changes. The clock generator 3 performs a time discretization of the varying voltage corresponding to the varying temperature. If the temperature has changed and has reached a certain constant level, then i threshold indicator cells are energized ... 2.1. This threshold indicator cell is quenched, the previous cell of which is not excited, and the latter is excited. Dena, i.e. All the previously excited threshold cells 2, l, ..., 2 are sequentially quenched, except for the excited cell 2.1, the first photodiode 3I of which does not receive an optical signal from the first LED 32 of the next unexcited cell 2 . (i + +1). A constant temperature is indicated by only one excited threshold indicator cell. If the temperature has changed, then clock pulses appear on the feedback bus 10, the first pause between the pulses is the quenching of the excited threshold cell and the device is again ready for operation. 1 hp f-ly, 1 ill. i (L

Description

with

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The invention relates to instrumentation and can be used in various industries where temperature measurement is required with information.

The purpose of the invention is to simplify the construction of the thermometer and increase the informativeness of the visual display of the measured temperature and its change.

The drawing shows a diagram of an electronic thermometer.

The thermometer contains a measuring transducer 1 for temperature, n threshold indicator cells 2.1, 2.2, ..., 2.n placed in a ruler, a clock generator of 3 pulses, an analog switch 4, the first 5 and second 6 logic elements 2I- NOT, inverter 7, control bus 8, signal bus 9, feedback bus 10, two differentiators 51 and 12, each of which contains a capacitor 13, resistors 14-16, a composite transistor 17, the base of the composite transistor 17 being connected to the first capacitor plate 13 and to the common first terminals of resistors 14 and 15, about A voltage divider, the second transponders of which are connected respectively to the power bus 18 and to the common bus 19, the second capacitor plate 13 is connected to the output of the temperature transducer 1 to voltage and to the information input 20 of the analog switch 4, control, input 21 which is connected to the first input of the first element 2I-NOT 5, to the control pin 8 and to the output of the second element 2I-NOT 6, the first input of which is connected to the collector of the composite transistor 17 of the first differentiator II and the first output of the load resistor 16 , the second output of which is connected to the power bus 18; the second input of the second element 2I-NOT 6 is connected to the output of the inverter 7, the input of which is connected to the collector of the composite transistor 17 of the second diff

at the first terminal of the load resistor 16, the second terminal of which is connected to the power bus 18, the emitter of the composite transistor 17 of each differentiator 11 and 12 is connected to the common bus 19, the output of the analog switch 4 is connected to the signal bus 9, the clock generator 3 is connected to the second entrance of the first ele

5 0 5 0 5 0 5

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ment 2I-NOT 5, the output of which is connected to the bus 10 feedback. Each threshold indicator cell 2.1, ..., 2.n contains a bipolar transistor 22, a first 23, a second 24 and a third 25 resistors, a first separating diode 26, an indicator LED 27, a feedback LED 28, a reverse photodiode 29 connection, the anode of which is connected to the base of the transistor 22 and to the first terminals of the first 23 and second 24 resistors, the second terminals of which are connected respectively to the cathode of the first separation diode 26 and to the common bus 19 to which the emitter of the transistor 22 is connected, between which collector and bus 18 meals included after a third resistor 25, an indication LED 27, and a feedback LED 28, which is optically coupled to the feedback photodiode 29 of its threshold indicator cell, whose cathode is connected to the feedback bus 10. The anode of the first separation diode 26 is connected to the signal bus 9. In each threshold indicator cell 2.1, ..., 2. (p-1), except for the last 2, a second separation diode 30 is inserted, the first photodiode 31 of quenching, the anode of which is connected To the anode of the second separation diode 30, the cathode of which is connected to the control bus 8, in each threshold indicator cell 2.2, ..., 2. Pe except for the first 2.1, the first quench LED 32 is inserted, connected in series to the collector circuit of transistor 22 and optically connected Zannda with the first photodiode 31 ha previous threshold indicator cell. In each threshold indicator cell 2.2, ..., 2. (p-1), except for the first 2.1 and last 2.P, contains the second photodiode 33 of quenching, the anode of which is connected to the cathode of the first photodiode 31 of quenching, the cathode of the second photodiode 33 ha - Sheni, and in the first indicator cell 2.1 - the cathode of the first photodiode 31 of quenching is connected to the base of the transistor 22. In each threshold indicator cell 2.1, ..., 2. (n-2), except for the last two 2. (n- | ) and 2.p, will introduce. the fourth resistor 34, the third isolation diode 35, the second light emitting diode 36, the anode of which is connected to the first output of the fourth resistor 34 and to the anode of the third separation anode 35, the cathode of which is connected to the collector of transistor 22, and the second output of the fourth resistor 34 is connected to the bus 18, a common bus 19 is connected to the cathode of the second shutoff LED 36, which is optically coupled to the second photodiode. 33 of the next blanking of the threshold indicator cell.

The thermometer works as follows.

Resistors 14 and 15 of the first II and second 12 differentiators are selected in such a way that in the normal state, i.e. when the output voltage of the converter 1 is constant, the composite transistor 17 of the first differentiator 11 is in the closed state, and the output of this differentiator is voltage 1, and the composite transistor 17 of the second differentiator 12 is in the open state and at its output O. The working points of the composite transistors 17 and 11 of the second 12 differentiators are selected at the beginning and end of the active region of the transistor, respectively. The capacitor 13 and the resistance formed by the parallel connection of resistors 14 and 15 and the resistance of the transistor 17 form a differentiating RC-chain from the base, at the output of which the voltage varies in proportion to the rate of change of voltage Upp at the output of converter 1. If the speed

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voltage change - - Oh, then

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The RC outputs of the differentiators 11 and 12 have a positive voltage, which opens the composite transistor 17 of the first differential 11 due to its large gain and the O voltage appears at the output of the first differentiator 11. The composite transistor 17 of the second differentiator 12 goes into a deeper presence

If, Oh, then at the output RSCPU

chains of differentiators 11 and 12 there is a negative voltage that closes the composite transistor 17 of the second differentiator 12 due to its large coefficient

and the voltage appears at its output. The composite transistor 17 of the first differentiator 11 is even more closed.

The threshold indicator cells 2,1 ,,,, 2, n with the help of resistors 23 and 24 are configured so that the threshold voltage for temperature to voltage converter 1 with a linear characteristic for the i-th threshold indicator cell, where i 1, ) 2 ,,,., P, defined as

Ur, opor.i UMHH + (i-P

/ iax UMVIH

P

where, H 5 UMOKC, respectively, is the lowest and highest voltages corresponding to the lowest and highest measured temperatures. Moreover, the threshold indicator cells, by appropriate selection of voltage dividers assembled on resistors 23 and 24, allow for the linearization of any types of thermal converters with a high degree of accuracy.

If the inlet temperature of the preform 1 changes and reaches the HeKOTOpqro level, which corresponds to the voltage Uno about; The control bus 8 forms a voltage 1, Therefore, at the output of the analog switch 4, a voltage is present; the feedback bus 10 pulses the clock generator 3. At the time when the bus 10 voltage is voltage 1, i threshold indicator cells 2.1, ,, ,, ,, 2, i are energized along the collector circuit of the transistor 22 In each of these indicator cells, a current flows causing the indication LED 27 to turn on, an LED. 28 feedback and the first LED 32 is dimmed. The light flux from the LED 28 is fed to the feedback photodiode 29, its reverse resistance decreases sharply and the base of the transistor 22 arrives, and the additional current, while maintaining the transistor 22 in the open state. The second light emitting diode 36 is turned on, as it is shunted by the third separation diode 35 and the collector-emitter junction of the open transistor 22.

The luminous flux from the first light-emitting diode 32 is damped to the photodiode 31 to quench the previous threshold indicator cell, but not to quench, because the control bus 8 has the voltage 1. During the pause between the pulses on the bus 10, the feedback feedback photodiode 29 The triggered threshold indicator cells 2.1, ..., 2.1 turns on in the forward direction, because the feedback bus 10 is present on the feedback bus O. All previously excited threshold indicator cells are extinguished. In this way, the clock generator 3 performs a time discretization of the varying voltage corresponding to the varying temperature. If the temperature has changed and reached a certain constant level, which corresponds to the voltage, and so on; const, then 1 threshold indicator cells were energized 2.15 ..., 2.i. Voltage O is set on the control bus, so voltage 1 appears on the feedback bus 10, causing constant excitation of i threshold indicator cells 2.1, ..., 2, i and relieving the voltage from the signal bus 9 by locking the key 4. Since the second threshold indicator cell 2.2 is excited, the luminous flux from the first light-emitting diode 32 of this cell goes to the first photodiode 31 of the first threshold indicator cell 2.1. The reverse resistance of this photodiode decreases sharply, the first threshold indicator cell 2, lj is quenched because the control bus 8 has voltage O, which causes the transistor 22 to close. The third isolation diode 35 of this cell turns on in the opposite direction, therefore through its second the quench LED .36 begins to flow. The luminous flux from this quench LED enters the second photodiode 33 of quenching the second threshold indicator cell 2.2, reducing its reverse resistance. Since the third threshold indicator cell 2.3 is excited, the reverse resistance of the first photodiode 31 damping of the second threshold indicator cell 2.2 is also small, which leads to the damping of the latter.

five

0

Consequently, the threshold indicator cell is quenched, the previous cell of which is unexcited, and the last one is excited, i.e. consecutive quenching of all previously excited threshold indicator cells 2.1, ..., 2. (1-1), except for excited cell 2.1, is performed,

0 to the first photodiode 31 of which no optical signal is received from the first LED 32 of the next unexcited cell 2 (i + +1).

Thus, a constant temperature is displayed by only one excited threshold indicator cell. If the temperature has changed again, the clock pulses appear on the feedback bus 10 and the first pause between the pulses suppresses this excited threshold indicator cell and the device is ready for operation again.

5 In the last threshold indicator cell 2.n, photodiodes are not quenched, because it is quenched via feedback bus 10,

Claims (1)

1. An electronic thermometer containing a temperature-to-voltage measuring transducer connected to the input of a logic device with a display unit of the measured value and the tendency of its change, characterized in that, in order to simplify the design of the thermometer and increase the informativeness of the visual display of the measured temperature value and its changes, the logical device is equipped with p-threshold indicator cells, placed in a ruler, a pulse generator, an analog key, information the ion input of which is connected to the code of the temperature-to-voltage transducer and its output to the signal line common to all threshold indicator cells, two differentiators connected by inputs to the output of the temperature measuring transducer, the first 5 and the second logic elements 2I-HE and an inverter connected between the output of one of the differentiators and one of the inputs of the second logical five 0 five 0 element 2I -NE, the second input of which is connected to the code of another differentiator, and its output - to the control input of the analog key, control bus and one of the inputs of the first logic element 2I-NO, whose second input is connected to the output of the clock generator and its output is connected to a common for all threshold indicator cells by a feedback bus, each of the threshold indicator cells being filled in the form of a bipolar transistor, the first, second and third resistors, the first separating diode, the anode of which connected to the signal bus of the feedback LED, the indication LED, the feedback photodiode whose cathode is connected to the feedback bus, and its anode is connected to the base of the transistor and to the combined first terminals of the first and second resistors, whose second terminals connected respectively to the cathode of the first isolation diode and to the common bus to which the emitter of the transistor is connected, between which the collector and the power bus are connected in series the third resistor, the LED indicator and the reverse LED with In connection with the optically coupled feedback photodiode of its threshold indicator cell, each threshold indicator cell, with the exception of the latter, is equipped with a second separation diode and a first photodiode of quenching, the anode of which is connected to the anode of the second separation diode, and the cathode is connected to the bus controls, each threshold indicator cell; with the exception of the first one, it is equipped with a first blanking LED connected in series to the collector circuit of the transistor and optically connected with the first photodiode about Q five the quenching house of the previous threshold indicator cell, each threshold indicator cell, with the exception of the first and last, is equipped with a second quenching photodiode, the cathode of which is connected to the base of the transistor and its anode to the cathode of the first photodiode quenching; Each threshold cell, with the exception of the last two, is equipped with a fourth resistor, a third isolation diode and a second LED, whose cathode is connected to a common bus, and its anode is connected to the first output of the fourth resistor and to the anode of the third separation diode, the cathode is connected to a transistor collector, the second blanking LED being optically connected to the second blanking photodiode of the subsequent threshold indicator cell, the second terminal of the fourth resistor is connected to the power bus, and the cathode first fotodiyda of blanking in the first threshold of the indicator cell is connected to its base of transistor .. 2, Thermometer according to claim 1, which is based on the fact that each of the differentiators is equipped with a composite transistor, a collector; that is connected via a load resistor to the power bus, and its emitter is connected to a common bus, a resistive voltage divider turned on between the power supply terminal and the common bus and its midpoint connected to the base of the transistor, and a capacitor connected between the base of the transistor and the output of the temperature measuring transducer, the collector of one of the differentiators connected to the input of the inverter a, and the collector of the transistor of another differentiator with the second input of the second logic element 2I-NEF