JPS6217624A - Temperature measuring apparatus - Google Patents

Abstract

PURPOSE:To make it possible to measure temp. over a wide temp. range with high accuracy in spite of the non-linearity of a temp. sensor, by processing the temp. data of a memory corresponding to the digital signal of an A/D converter part wherein the address of the memory is accessed. CONSTITUTION:The addresses of memories 5, 6 in which the temp. data detected from temp. detection means 1a-1f were written through a signal selection means M are directly accessed by the digital signal outputted from an A/D converter part 4 and the temp. data of the means 1a-1f read from the memories 5, 6 corresponding to the digital signal of the converter part 4 are processed by a processing part. By this method, the selective display of the linearized temp. data of a plurality of detection circuits can be performed without requiring a special linearization circuit and the processing part comes to a stand-by state until the A/D conversion of the converter part 4 is finished and a highly accurate measured value can be obtained over a wide temp. range.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is capable of measuring temperature by converting a temperature change into a resistance change using a thermistor, resistance temperature detector, or thermocouple, and measuring this resistance value. The present invention relates to a temperature measuring device using a temperature detecting means that performs the following steps.

[Conventional technology]

Conventionally, temperature has been measured using temperature detection means using a thermistor, a temperature resistor, or a thermocouple as a temperature sensor, which converts a temperature change into a change in resistance. However, since the resistance change of these elements is not linear with respect to temperature change, some type of linearization function is required to increase measurement accuracy and to use them over a wide temperature range. For example, if we take a thermistor as an example of a device with the most dramatic resistance change, the thermistor has temperature-resistance change characteristics as shown in FIG. In FIG. 3, the temperature T is plotted on the horizontal axis and the resistance value R is plotted on the vertical axis. Since it is not possible to directly read the temperature from the resistance value with such a change characteristic shown in FIG. 3, a temperature detection means having a linearization function as shown in FIG. 91 is employed to linearize this. In the figure, (/a) is a temperature detection means, (1) is a thermistor connected in parallel with a resistor (c), and this is further connected to a resistor (3).
and is connected between the power supply P of the temperature detection means (/a) and the ground 8. The configuration is such that the voltage V between the ground E and the terminal is taken out as an output.

The temperature detecting means in the conventional temperature measuring device is constructed as described above, and the output voltage V shows a change as shown in FIG. 5 with respect to temperature. That is, if the horizontal axis is the temperature IT and the vertical axis is the voltage (2), the output voltage decreases almost linearly as the temperature rises. If resistances (, 2) and (3) are appropriately selected, it is possible to make this graph almost linear.

[Problems that the invention is supposed to solve]

In the case of the above-mentioned conventional temperature measuring device, the linearity detection means needs to have characteristics closer to a straight line when measuring a wide temperature range or when high-precision temperature measurement is required. For this purpose, a linearization circuit or device called an IJ nearer is required. However, since such circuits and devices use a large number of precision resistors, variable resistors, and operational amplifiers, adjustments are complicated and, if high-precision parts are provided, they are extremely expensive.

This invention was made to solve this problem, and although it uses a temperature sensor with non-linearity, it does not require a linearization circuit with a complicated configuration.
The object of the present invention is to obtain a temperature measuring device that can obtain highly accurate measured values over a wide vortex i range at a plurality of detection locations.

[Means for solving problems]

The temperature measuring device according to the present invention includes, for example, a thermistor,
For example, the output voltages of a plurality of temperature detection means using temperature sensors such as thermocouples are converted into digital signals by an A/D converter through a signal selection means consisting of a multiplexer circuit, The Yamaga data corresponding to this digital signal written in the
The data is read out depending on this digital signal and processed by a processing section consisting of a microcomputer, for example, and the processing section is placed in a wait state by a read signal from the processing section until the conversion is completed in the A/D conversion section. have the means.

[Effect]

In this invention, the address of the memory where the temperature data detected from the plurality of change detection means is written via the signal selection means is directly accessed by the digital signal output from the A/D conversion section, and the address of the memory is directly accessed by the digital signal output from the A/D conversion section. Since the m degree data of the plurality of temperature detection means correspondingly read out from the memory is processed in the processing section, the linearized temperatures of the plurality of detection points can be selected without the need for a special linearization circuit. Furthermore, the processing section enters a wait state until the A/D conversion section OA/D conversion is completed.

〔Example〕

Hereinafter, FIG. 1 is a block circuit configuration diagram showing one embodiment of the present invention. In the figure, (/a) to (/f) are temperature detection means including a thermistor (1) as a temperature sensor. Here, the thermistor (1) is connected in parallel with the resistor (2) and in series with the resistor (3). (M
) is a multiplexer circuit section as a signal selection means, which selects an arbitrary temperature detection means (/a) from a selection signal SK from a processing section (not shown) consisting of a microcomputer, for example.
~(/f) can be selected. 6C1 This A/D converter (hereinafter referred to as the A/D converter) is an analog-digital converter (hereinafter referred to as the A/D converter).
) is inputted with the output voltage of the temperature detecting means (/a) to (/f) selected by the temperature detecting means (/a) to (/f) and converted into a digital signal. (y
) and (A) are memories, which are composed of ROMICs that do not lose data even if there is a power outage. These memories (j) and (A) have a chip select signal terminal (ta).
), (Aa), read signal terminal (rb), (xb)
, address terminals (jc), (6c) and data terminals (,
td) and (6d) are provided. (pa) is A/D
The digital signals (D, ~D1.) from the conversion unit (RI) are transferred to the memory (t), address terminals (jc) of (4), (
The address of memory (, t), (a) is directly accessed by this digital signal on the data sending line for input to AC). (Ilb) is a signal terminal (rb
), (6b) and the conversion end signal output line for applying to the A/D conversion control unit (10), read signal terminals (jb) and (4b) are the conversion end signal (ubB).
becomes active. (sdo), (jzuy)
, (AdQ).

(Ad?) transfers the read temperature data to the data terminal (r
d), (6+: A control signal line applied to a data line serving as a reading means for sending data from D to a processing unit (not shown) consisting of, for example, CPt7.

(va), (?b) accept decode signals (ta), (7b) and read signal (r) from the processing section (not shown), and send the output to the chip select signal terminal (ja),
The chip select signal terminals (ja) and (Aa) are activated by the output from each AND gate (ta) and (vb).

(//) takes the outputs of AND gates (9a) and (?b) as its inputs, and one terminal (/2) of AND gate (/J).
This is a gate circuit for applying an output to a), and this AND gate (/) applies a conversion end signal (u) from the conversion end signal output line (da b) to the other terminal (/2b).
bB) and outputs a wait signal (WAI'I') to the processing section (not shown). Memories (3) and (6) are examples. ,. □□O. YuA8.73I, YuA, ~A/J's/
Since it is a 3-bit m configuration, the output of the A/D converter (1
The numbers may also be divided into 73-bit configurations. For example, Memo IJ
If the capacity of (j) and (A) is not to use all j kilobytes but only da kilobytes, the A/D converter (41
) need only have a 72-bit output signal. In that case, the address signal terminal A/J is set to H depending on the memory area to be used.
'E or L (not shown). The data structure of the memories (!;) and (6) is -'-D, which is a g-bit structure. When this S bit is used as a BCD signal, only 1 digits of BCD signal can be configured, so if 5 memo IJ (r) and (z) are used, it is possible to configure 7 digits of BCD or 4IVT. . In this embodiment, the memory (1) and (6) -
This example shows a case where the BCD is configured using 41 digits.

Note that this applies to the case of a BCD code, and is not limited to this; if it is configured with a binary signal, it can be configured with up to 76 bits.

The memories (5) and (6) are pre-written with the address K corresponding to the digital output signal of the A/D converter (R) and the @ degree data corresponding to the digital output signal as the stored contents. .

In the @variable measuring device configured as described above, for example, the output voltage and temperature data of the temperature detection means (/a) to (/f) using thermistors (1) shown in the characteristic graph of FIG. By measuring or calculating the relationship between
Remember it. In Figure 1, for example, point Q on the characteristic graph is the point when the temperature is 0°C, and the output voltage at this time is 2. O
It is v. The point -/ is a point at 30°C, and the output voltage at this time is i/v. Similarly, point 2 is a point at -30°C, and the output voltage at this time is 3.2V. Although the graph is not a straight line, it is possible to obtain a fixed curve as long as the values of the series resistance (3) and parallel resistance (2) are determined. Therefore, the value KO* corresponding to each voltage value is determined in /rILV steps or 2 mV steps of the output voltage, and then when this output voltage value is used as an address signal, the corresponding @
Note the degree value IJC! If you write BCD 4' digits to the address in ;>, C1,>, with the above configuration,
Temperature data corresponding to the output voltages of the at detection means (/a) to (/f) can be obtained from the memories (yo) and (6) as a 3-digit BCD code. This at data is stored in memory (
r), data terminals (3d) and (6d) of (A)
Data lines (rd, )), Ddy) +
It is input to the processing section (not shown) via (6a□) and (''?).

This vortex data can be read in the following manner. First, A/D conversion is performed at fixed time intervals using the control signal (10aA) of the A/D conversion control unit (10) in accordance with the selection signal S, and when the A/D conversion is completed, the end signal (
+bB) is output. If this end is active, the contents of the memo IJ (r), (z) are read from the data terminal (3d) or (6d). In this case, the decode signals (RIa) and (7b) are sequentially output at regular time intervals in order to sequentially read the temperature data of the memories (J-) and (A). Therefore, even if the memory (r), (a) or ), the read operation is kept in a wait state until the end signal (!bB) is output.
The lead is completed by exiting.

In the above embodiment, the output voltage is /mV or 211
Although the output voltage is shown in increments of V, if the capacity of the memory is increased, the scale of the output voltage in FIG. 2 can be made in smaller increments, for example, 0. By storing the corresponding at in increments of jr m V, even higher accuracy can be obtained.

Note that in this embodiment, the A/D converter (tI) is configured to create a ready/wait state on the reading side assuming a high-speed type element, but the A/D converter (tI) is configured to create a ready/wait state on the reading side. It is also possible to configure from

Further, in this embodiment, the multiplexer circuit section (M) has 6
Although the six-circuit input type is used, in which the outputs of the IT detection means (/a) to (/f) are input, a larger number of temperature sensors can be connected by providing a larger number of circuits. Further, although the multiplexer selection signal S is a signal from an external processor such as a microcomputer, the present invention is not limited thereto, and a manually set signal may be used, for example. Further, in this embodiment, a thermistor has been described, but the present invention can also be applied to a case where a thermocouple or a temperature-measuring resistor is used as a temperature sensor. Further, the outputs of the memories (j) and (A) can be outputted to a display circuit, branched out, and inputted to a computer or the like for data processing. Furthermore, if it is incorporated into a device that uses an arithmetic processing device such as a microcomputer, the memory of the microcomputer can be used and the control circuit can be simplified. Furthermore, if an ini display, target temperature setting means, and temperature comparison means are added, the present invention can be used as a temperature regulator or an alarm, and the scope of application of the present invention is extremely wide.

〔Effect of the invention〕

This invention is based on the above explanation, and the address of the memory is A/A.
The temperature sensor is directly accessed by the digital signal from the D converter, and the temperature data read out from the memory in response to this digital signal is processed by the processor, allowing a wide temperature range even though the temperature sensor has non-linearity. It is said that it is possible to obtain highly accurate measurement values over a wide range of temperatures, and that it does not require the complicated linearization circuits of conventional devices; it can perform multiple temperature measurements at low cost with a simple circuit, and has an extremely wide range of applications. be effective.

[Brief explanation of the drawing]

Fig. 1 is a block circuit configuration diagram showing an rIA degree measuring device according to an embodiment of the present invention, Fig. 1 is a characteristic diagram of 6 degrees versus voltage to explain the operation of Fig. 1, and Fig. 3 is a general diagram. Figure 9 is a circuit diagram showing an example of a general linearization circuit for linearizing the thermistor characteristics. Figure S is the temperature-resistance characteristic of the circuit in Figure 9. ! It is a characteristic diagram showing temporality. (1) is a thermistor, (/a) to (/f) are temperature comparison means, (i is an A/D converter, (r) and (6) are memories, (M) is a multiplexer circuit, (r) (10) is the read signal, and (10) is the A/D conversion control section. The same reference numerals in the figures indicate the same or equivalent parts. Tomari 3 Figure 4 Procedure Amendment (Voluntary) 1933. Exposure! 9 1

Claims (6)

[Claims] (1) A plurality of temperature detection means for extracting signals according to temperature, a signal selection means for selecting signals from the plurality of temperature detection means, and a signal selected by the signal selection means for converting the signal into a digital signal. The A/D converter to convert and this A/D converter
a memory for storing temperature data corresponding to the output of the A/D converter; a reading means for reading the corresponding temperature data from the memory according to the output of the A/D converter and applying it to the processing section; and the processing section. A with the read signal from
1. A temperature measuring device comprising: a wait means for placing a processing section in a wait state until completion of /D conversion. (2) The temperature according to claim 1, wherein the A/D conversion operation of the A/D conversion section is controlled by an A/D conversion control section connected to the A/D conversion section. measuring device. (3) The temperature measuring device according to claim 1 or 2, wherein each of the plurality of temperature detecting means includes a thermistor, a parallel resistor, and a series resistor. (4) The temperature measuring device according to any one of claims 1 to 3, wherein the memory is constituted by a ROMIC. (5) The temperature measuring device according to claim 1, wherein the processing section is constituted by a microcomputer. (6) The temperature measuring device according to claim 1, wherein the signal selection means is constituted by a multiplexer circuit section.