SU838407A1

SU838407A1 - Digital thermometer

Info

Publication number: SU838407A1
Application number: SU782623332A
Authority: SU
Inventors: Владимир Наумович Пеклер; Владимир Владимирович Пятшев; Александр Иванович Иванов
Original assignee: Челябинский Политехнический Институтим. Ленинского Комсомола; Челябинский Ордена "Знак Почета"Завод "Теплоприбор"
Priority date: 1978-05-10
Filing date: 1978-05-10
Publication date: 1981-06-15

Description

1one

Изобретение относитс к температурным измерени м, а именно к цифровым термометрам с коррекцией нелинейности термопреобразовател .The invention relates to temperature measurements, namely to digital thermometers with correction of non-linearity of the temperature transducer.

Известен цифровой термометр, содержащий термометр сопротивлени , эталонный резистор, цифроаналоговый преобразователь, генератор счетных импульсов. В этом устройстве компенсаци нелинейности термометра сопротивлени достигаетс путем включени в цепь питани первого цифроаналогового преобразовател второго цифроаналогового преобразовател l.A digital thermometer is known that includes a resistance thermometer, a reference resistor, a digital-to-analog converter, and a counting pulse generator. In this device, compensation for the nonlinearity of the resistance thermometer is achieved by connecting the first digital-to-analog converter to the second digital-to-analog converter l in the power circuit.

Однако это устройство не обеспечивает высокой точности измерени температуры в широком диапазоне темг ператур.However, this device does not provide high accuracy of temperature measurement in a wide range of temperatures.

Наиболее близким к предлагаемому вл етс цифровой термометр, содерЖсцций термопреобразователь, включенный в измерительную схему, выход которой соединен со входом аналого-цифрового преобразовател , блок управлени , соединенный с управл ющими входами блока индикации и аналогоцифрового преобразовател 1.The closest to the present invention is a digital thermometer containing a thermal converter included in the measuring circuit, the output of which is connected to the input of the analog-digital converter, the control unit connected to the control inputs of the display unit and the analog-digital converter 1.

Недостатком известного цифрового термометра вл етс .низка точность /измерени температуры, поскольку онA disadvantage of the known digital thermometer is the low accuracy / temperature measurement, since it is

не может компенсировать нелинейность термопреобразовател в широком диапазоне температур.cannot compensate for the non-linearity of the thermal converter in a wide range of temperatures.

Цель изобретени - повышение точности измерени температуры.The purpose of the invention is to improve the accuracy of temperature measurement.

Поставленна цель достигаетс тем что в цифровой термометр введены коммутатор , блок пам ти и микропроцессор , входы которого соответственно соединены с выходом аналого-цифрового преобразовател , блока пам ти и блока управлени , а выход соединен с блоком индикации, причем вход коммутатора соединен с выходом блока управлени , а выходы соответственно соединены с измерительной схемой и блоком пам ти. This goal is achieved by switching a digital thermometer to a switch, a memory unit and a microprocessor, the inputs of which are respectively connected to the output of an analog-digital converter, a memory unit and a control unit, and the output is connected to a display unit, the switch input and the outputs are respectively connected to the measuring circuit and the memory unit.

На чертеже показана блок-схема предлагаемого устройства.The drawing shows a block diagram of the proposed device.

Цифровой термометр содержит термопреобразователь 1, включенный в измерительную схему 2, аналого-цифровой преобразователь 3, коммутатор 4, блок 5 пам ти, микропроцессор 6, блок 7 управлени и блок 8 индикации .The digital thermometer includes a thermal converter 1 included in the measurement circuit 2, an analog-digital converter 3, a switch 4, a memory unit 5, a microprocessor 6, a control unit 7 and a display unit 8.

Цифровой термометр работает следующим образом.Digital thermometer works as follows.

Claims

The characteristic of any thermal converter in an analytical form can be represented in the form of the polynomial wi and -S 1--0-0 where B is the value of the output parameter of the thermal converter; в - measured temperature value; ; —constant coefficients that are chosen so that the approximation error of the true temperature dependence does not exceed a given value in the entire measurement range. Since the true value of the temperature is judged by the measured value of the parameter Bg, the approximating dependence of the form (Вв, к) ,,, (2 where c- ;; constant coefficients that can be determined in advance. When measuring temperature, the signal from the output of the thermal converter 1 enters the measuring circuit, 2, where it is amplified and fixed then switches to analog-to-digital converter 3. Switch 4 switches the gain of the measuring circuit depending on the size of the input signal coming from the thermal converter 1. The same switch switches the outputs of memory block 5 by applying coefficients d to the microprocessor input; a polynomial corresponding to a certain value of the gain of the measuring circuit 2. From the output of the analog-to-digital converter, the signal arrives at the input of the microprocessor 6, to the other inputs of which The coefficients c., -, d, j - from the memory block. The algorithm for calculating the c values Q in accordance with formula (2) is laid in control block 7, which simultaneously controls the operation of the analog-digital converter, switch and display unit 8 The accuracy of temperature measurement can be ensured in accordance with the specified requirements by appropriate selection of the approximate expression. The presence of new elements of the switch, microprocessor and memory unit distinguishes the proposed digital thermometer from the known device, since it provides an increase in the accuracy of temperature measurement, which makes it possible to expand the scope of application of the digital thermometer. A digital thermometer comprising a thermal converter included in a measurement circuit, the output of which is connected to the input of an analog-digital converter, a control unit connected to the control inputs of the display unit and an analog-digital converter that differs from measurement accuracy; a switch, a memory unit and a microprocessor are entered into it, the inputs of which are respectively connected to the output of the analog-digital converter, the memory unit and the control unit, and the output is connected to indication module, the switch input is connected to the output of the control unit, and the outputs are connected respectively to the measuring circuit and the input of the memory block. Sources of information taken into account during the examination 1. USSR author's certificate No. 502237, c. 01 K 7/16, 1974.

2. USSR author's certificate No. 559131, c. C.01 K 7/16, 1975 (prototype).