SU1081437A2 - Device for measuring temperature - Google Patents

Description

The invention relates to the field of temperature measurements, namely, devices for measuring temperature with digital correction of non-linearity of a temperature transducer.

According to the main auth. 901846 discloses a temperature measuring device comprising a thermal converter connected to the converter input of a thermal converter in a time interval, the output of which is connected to a control input of a switch connecting a counting pulse generator to a binary counter, the information input of which is connected to the output of a memory block. and the output is connected to a digital display unit, a binary counter, the input of which is connected to the key output, and the output is connected to the address input of the memory unit Cl3.

The disadvantages of this device are low measurement accuracy, due to the high cost of the lower bit of the correction number stored in the memory unit and low speed, because one measurement of temperature requires two conversion cycles: one to determine the number of the measuring range segment which is the value of the measured value, and the other is for correction.

The aim of the invention is to improve measurement accuracy and speed.

The goal is achieved by introducing a frequency divider and a pre-recording pulse shaper into the temperature measuring device, the input of which is (Connected to the input of a binary counter and the output connected to the recording input of a binary-decimal counter, while the frequency divider is connected between the output of the key and input binary counter.

FIG. 1 is a block diagram of the device; in fig. 2 - graphs that show his work.

The device contains a thermal converter 1, a converter 2 of the output signal of the thermal converter in a time interval, a key 3, a connecting generator 4 of counting pulses with a binary-decimal counter 5, a digital display unit 6, a frequency divider 7, a binary counter 8, a pre-write pulse driver 9, an output which is connected to the input of the first decade of the counter 5, the memory block 10, the address input of which is connected to the double-counter viola of the counter 8, and the information output to the information input of the binary-decimal counter and 5.

The device works as follows.

5 The number of pulses at the output of the switch, proportional to the electrical signal of the thermal converter, is fed to the binary-decimal counter 5, as well as to the input of the frequency divider 7.

e Divided by the divider 7, the number of pulses is counted by the counter 8 and determines the address of the corresponding correction number in the memory block 10. To the output of the frequency divider, the input of the preampler pulse generator 9 is connected, the output of which is connected to the write enable input of the counter 5. The prerecord pulse is fed every time between the pulses,

0 setting the first decade of the counter 5 to zero, and the next pulse coming from the key 3. Thus, the correction number stored in the cell of the memory block 10, extracted by the counter 8, is summed with the number of pulses counted by the counter 5. For example, the practical implementation of the device coefficient analog-to-digital converter

0 was chosen so that each pulse at the output of the key 3 corresponds to a temperature increment not exceeding 0.1 s, and the division factor of the divider 7 is chosen equal to 20.

5, each pulse arriving at the input of counter 5 corresponds to approximately O, 1 ° C, and the correction step 4t is practically equal to 2®С (in Fig. 2, where 4Nj (is the correction number of imJJ pulses, is N. f (t ) - dependence of the number of pulses N at the input of the counter 5 on temperature, K Kt - dependence of the Number of pulses N at the output of counter 5 on temperature, K coefficient of proportionality).

5 Since the correction number is added repeatedly during the measurement cycle, at equal volumes of the memory block, the price of the lower digit of the correction number is lower in comparison with the known device, and therefore, the correction accuracy is significantly increased. I

5 The presence of new elements in the device — a frequency divider and a pre-recording pulse former — makes it possible to reduce the error from the residual nonlinearity of the thermal converter and to increase the speed of the device by two times.

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Claims (1)

. DEVICE FOR MEASURING TEMPERATURE by ed. No. 901846, characterized in that, in order to increase the accuracy of measurement and speed, a frequency divider and a pre-write pulse shaper are introduced into it, the input of which is connected to the input of the binary counter, and the output is connected to the recording input of the binary-decimal counter, while the frequency divider It is connected between the key output and the binary counter input.