JPH0548408B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermometer and an electronic temperature measuring device for equipment observation and maintenance.

[Conventional technology]

This type of electronic temperature measuring device has been adopted in many fields in recent years, and in particular, for home use, it is rapidly becoming popular as an alternative to conventional mercury thermometers due to its ease of use.

However, with conventional temperature measuring instruments of this type, it is not possible to check the measurement results from the previous use (hereinafter, temperature measurement will be abbreviated as temperature measurement, and the measurement results from the previous use will be referred to as the previous temperature measurement value), such as with mercury thermometers. If you want to compare the measurement result obtained from the current use (hereinafter referred to as the current temperature measurement value) with the previous temperature measurement value to find out the temperature change, the measurement result obtained each time you use the It was very troublesome as it was necessary to memorize the temperature values or write them down.

In order to solve this problem, an electronic temperature measuring device was proposed that had a memory function and retained the temperature measurement results even after the power was turned off, allowing them to be read out and displayed as needed (Published in Japanese). : Electronics Digest Co., Ltd., December 10, 1975
Japan “CMOS IC Handbook” pp. 287-292
(see page).

[Problem that the invention seeks to solve]

The above conventional technology can display the previous temperature measurement value and the current temperature measurement value, but since these are displayed on the same display unit, it is difficult to see how much the current temperature measurement value has changed from the previous temperature measurement value. In order to know the temperature, the user must display these alternately and judge the size relationship between the two, and in addition, a switch must be installed separately from the main switch for setting the temperature measuring device to operate or deactivate. The previous temperature measurement value can be displayed by operating the switch for reading out the temperature measurement value in the stored memory section, so it is necessary to use two switches and operate them separately, which makes the operation complicated. Easy to operate incorrectly. For this reason, it is not particularly suitable for home use, such as a thermometer, mainly used by women and girls.

[Means to resolve the problem]

This invention was made in view of the above circumstances, and is equipped with a function to memorize the current temperature value and the previous temperature value, and can be set to start or stop by operating a single switch. , it is possible to switch between displaying the current temperature measurement value and displaying the difference between the current temperature measurement value and the previous temperature measurement value, making it possible to simplify switch operation and directly display temperature changes. It's something.

〔Example〕

The present invention will be described below with reference to embodiments and drawings. FIG. 1 is a block diagram showing an embodiment of the temperature measuring device according to the present invention, in which 1 is a switch, 2 is an oscillator, 3 and 4 are counters, 5 and 6 are RS type latch circuits, and 7 and 8 are Counter, 9 is a control unit, 10
Temperature measuring unit, 11 and 12 are storage units, 13 is a multiplexer, 14 is a display decoder, 15 is a display, 16
is an RS type latch circuit, 17 and 18 are falling edge detection parts, 19 to 22 are NAND gates, 23 to 3
0 is an inverter, 31 is a subtraction section, and 32 is a storage section.

In the figure, an oscillator 2, counters 3, 4,
7, 8, latch circuits 5, 6, 16, control section 9, temperature measurement section 10, display decoder 14, falling edge detection sections 17, 18, storage sections 11, 12, 32,
Each is in a reset state when the signal supplied to the reset terminal R is at a high level (hereinafter referred to as "H").

The switch 1 is a normally open switch that can be operated from the outside, such as a push button switch, a slide switch, or a reed switch installed inside the main body case (not shown) that is operated from the outside using a magnet. It is. When the switch 1 is not operated (that is, not closed), the counter 4 and the latch circuit 6 are reset with their reset inputs being "H", and one of the NAND gates 19 is reset. The input is "H".

The oscillator 2 is a CR oscillator or a crystal oscillator, and generates a reference clock MCK. This reference clock MCK is divided into a predetermined frequency by a counter 3 and supplied to counters 4 and 8 and a display decoder 14. The oscillator 2, the counter 3, and the falling edge detector 18 are connected to the MCK ON signal obtained by inverting the output of the NAND gate 19 with the inverter 23.
It can be switched between activated and deactivated by a signal.

The counter 4 and the latch circuit 5 constitute a determining section for determining whether the switch 1 has been operated. In this determination section, the counter 4 counts the clock from the counter 3 when the switch 1 is operated (the switch 1 is closed) and the reset is released. Counter 4 is the first n
When counting n, the _Qo output is inverted from a low level (hereinafter referred to as "L") to "H", and thereafter, every time the counter 4 counts n, the Qn output is inverted. Further, the counter 4 continues to count, and when its Q _o output has completed k rotations, its Q output is inverted from "L" to "H". That is, counter 4 further divides the frequency of the clock from counter 3, and the frequency division ratio for the Q output is set to k times the frequency division ratio for the Q _o output. In the following explanation, k=16.

On the other hand, the latch circuit 5 is set at the rising edge of the Q _o output of the counter 4 after the reset is released.
Its output is inverted from "H" to "L".

The counter 4 and the latch circuit 5 are in the reset state when the switch 1 is open, and the reset is canceled when the switch 1 is closed. The output is inverted from "H" to "L". Therefore,
This output indicates that switch 1 has been operated by inverting from "H" to "L".

The latch circuit 6 has a reset terminal R supplied with a GRST2 signal from an inverter 25, which will be described later. After the reset is released, the latch circuit 6 receives the Q output of the counter 4 and the inverter 24, which will be described later.
GRST1 signal to NAND gate 22 and inverter 2
It is set at the rising edge of the signal obtained by processing in step 6. When the latch circuit 6 is set, its Q output is inverted from L to H. However, even if the switch 1 is operated, if the operation connection period is shorter than the 16π count period of the counter 4, the counter 4 Q output goes from “L” to “H”
Since it is reset before it is reversed, the counter 6
is not set. On the other hand, when the operating period of the switch 1 is longer than the counting period of 16n of the counter 4, the latch circuit 6 is set. Therefore, the latch circuit 6 has a function as a determination circuit for determining whether the operation duration of the switch 1 after the reset is released is longer or shorter than the 16n count period of the counter 4.
The Q output of the latch circuit 6 is used to preset the counter 7, to control the switching of the multiplexer 13 as an SA signal, and to control the writing of the storage section 32.

The counter 7 is a binary counter of bits, and counts by one at the falling edge of the output of the latch circuit 5, and its output is inverted every time it counts. The Q output of the counter 7 is inverted by the inverter 24, and the NAND gate 19 outputs the GRST1 signal.
21 and 22. This counter 7 has its preset terminal PR supplied with the Q output of the latch circuit 6, and, as will be clear from the explanation later, forms a selection section for selecting whether to continue or stop the operation of the temperature measuring section 10. are doing.

The Q output of the latch circuit 5 is also supplied to the NAND gate 21, and the output of the NAND gate 21 is inverted to the inverter 25 to form the GRST2 signal. This GRST2 signal is transmitted to the latch circuit 6,
Counter 8, control section 9, temperature measurement section 10, display decoder 14, latch circuit 16, falling edge detection section 1
is supplied to each reset terminal R of 7, and
The signal is supplied to the falling edge detection section 18 as well as to the NAND gate 20 after being inverted by the NAND gate 27 .

Counter 8 further divides the clock from counter 3. The Ql output with the predetermined frequency division ratio is supplied to the control section 9, and controls the temperature measurement in the temperature measurement section 10, that is, the timing of temperature measurement. The _Qn output with a frequency division ratio twice that of the Ql output is supplied to the latch circuit 16 as a set input. The latch circuit 16 is set at the first rising edge of the Qm output of the counter 8 after the reset is released, and its output is inverted from "H" to "L". The falling edge of this output is detected by a falling edge detection section 17, and a MAX.R signal representing the falling edge is formed. This MAX.R signal resets the storage section 11, which is a D-type flip-flop, and erases the previously held temperature value. The output of the latch circuit 16 is also supplied to a NAND gate 20.

The temperature measuring section 10 is activated when the reset is released, and measures the temperature once every cycle of the Ql output of the counter 8. Each temperature measurement is completed immediately before the rising edge of the Ql output of the counter 8. Then, in synchronization with the rising edge of this Ql output, the temperature measurement value obtained at that time (hereinafter referred to as the current temperature measurement value) is compared with the temperature measurement value held in the storage unit 11, and the current temperature measurement value is When is large, MAX·φ is generated and the current measured temperature value is written in place of the previously held temperature measured value. Therefore, the temperature measuring section 1 is stored in the storage section 11.
Among the temperature values obtained so far after the 0 reset is released, the largest temperature value is held.

The storage unit 12 stores the “L” level obtained by inverting the output of the falling edge detection unit 18 with an inverter 29.
The measured temperature value held in the storage unit 11 is written by the MEMO·φ signal. The falling edge detection unit 18 detects the inverter 25 after the reset is released.
The falling edge of the GRST2 signal from the inverter 29 is detected, and the inverter 29 generates an "L" MEMO·φ signal representing this falling edge.

The multiplexer 13 is controlled by the SA signal that is the output of the latch circuit 6, and is
32 is selected and sent to the display section 14.

Further, although not shown, the multiplexer 13 is provided with an out-of-measurement-range detection means, and when the temperature measurement value from the selected storage section 11 is out of a predetermined measurement range, the display 15 displays this fact. for,
In addition to the temperature measurement value, data representing fixed numerical values, symbols, patterns, etc. is supplied to the display decoder 14.

Here, the above prescribed measurement range is 32.0℃~42.0℃
shall be. When displaying the current measured temperature value from the storage unit 11 selected by the multiplexer 13, if this value is less than 32.0°C, "LO°C" is displayed.
When the temperature exceeds 42.0℃, "HI℃" is displayed.

The display decode 14 and the display 15 constitute a display section. When the display decoder 14 is reset,
No signal is sent to the display 15, and for this reason,
The display 15 displays a blank display (that is, nothing is displayed). When the GRST2 signal becomes "L" and the display decoder 14 is reset, as long as the D _is PR signal obtained by inverting the output of the NAND gate 20 with the inverter 28 is "L", the output of the multiplexer 13 is decoded. and display 15
However, when the D _is PR signal becomes "H", the display decoder 14 is preset and is prohibited from accepting the output of the multiplexer 13, and the display 11 receives a signal to light all its segments. supply.

The subtraction unit 31 subtracts the subtracted temperature value from the storage unit 11 and the previous temperature measurement value from the storage unit 12 (here, the temperature measurement value held in the storage unit 12 is subtracted from the temperature measurement value held in the storage unit 12). subtract the measured temperature value) and output these difference data. This difference data consists of an absolute value S _ub (hereinafter referred to as a difference value) of the difference between these temperature values and code data S _io representing positive or negative.

A signal obtained by inverting the Q output (i.e., SA signal) of the latch circuit 6 with an inverter 30 is supplied to the storage section 32, and the rising edge of this Q output acts as a clock. The section 32 stores the difference data from the subtraction section 31. The difference data held in the storage unit 32 (the difference value is SUB and the code data is SIN) is read out and supplied to the multiplexer 13.

Next, the operation of this embodiment will be explained.
First, using the timing charts shown in FIGS. 2a and 2b, a case will be described in which, after the current temperature measurement value is obtained, the difference between the current temperature measurement value and the previous temperature measurement value is displayed.

In FIG. 1 and FIG. 2a, when not in use, the previous temperature measurement value _N When the power is turned on, the display 15 becomes activated. When a battery is used as a power source, the power is always turned on and the display 15 is in an operating state even when not in use. When the power is turned on, counter 7 is also reset, but the Q of counter 7 is
The output is "L" and the GRST1 signal is "H". At this time, the switch 1 is in the open state, the counter 4 and the latch circuit 5 are also in the reset state, and the output of the latch circuit 5 is "H", so the GRST2 signal obtained from the inverter 25 is also "H". For this reason, the display decoder 14 is in a reset state and the display 15 displays a blank display. Also, a latch circuit 6, a counter 8, a control section 9, a temperature measurement section 10, a latch circuit 16, a falling edge detection section 1
7 is also in the reset state. For this reason, the Q output of the latch circuit 6, and therefore the SA signal, is "L", and at this time, the multiplexer 13
The temperature measurement value from 1 (in this case, the previous temperature measurement value N _x ') is selected. Furthermore, since one input of the NAND gate 19 on the switch 1 side is "H" and the other input which is the GRST1 signal is also "H",
The MCK・ON signal is “H”, therefore,
The oscillator 2, counter 3, and falling engine detection section 18 are also in a reset state. Furthermore,
The GRST2 signal is "H" and the Q output of the latch circuit 16 is "H", so the D _is PR signal is "L".

The above is the state of each part when not in use.

In this state, when switch 1 is operated to close, the input on the switch 1 side of NAND gate 19 becomes "L", so the MCK ON signal becomes "L", and the oscillator 2, counter 3, and falling edge The detection unit 18 is reset. Therefore, oscillator 2 generates the reference clock MCK,
Counter 3 divides this frequency.

At the same time, counter 4 and latch circuit 5 are also reset, and counter 4 counts the clock from counter 3. When the counter 4 counts n, its Q _o output is inverted from "L" to "H", and the latch circuit 5 is set at the rising edge of this Q _o output. Therefore, the Q output of the latch circuit 5 is inverted from "H" to "L", the counter 7 counts by 1 at the falling edge of the output, and the output is inverted from "L" to "H".
The GRST1 signal is inverted from "H" to "L".

With the output of the latch circuit 5 and the inversion of the GRST1 signal to "L", the GRSR2 signal from the inverter 25 becomes "L", and the latch circuit 6, counter 8, control section 9, temperature measuring section 10, The display decoder 14, latch circuit 16, and falling edge detection section 17 are released from reset and become operational. Further, the falling edge of the GRST2 signal is detected by the falling edge detection unit 18, and the “L” MEMO·φ signal representing this falling edge is sent to the storage unit 18.
2. As a result, the previous temperature measurement value N _x ' held in the storage section 11 is written into the storage section 12.

On the other hand, since the output of the latch circuit 16 is kept at "H" and the GRST2 signal becomes "L",
The D _is PR signal becomes "H", the display decoder 14 is preset, and all segments of the display 15 are lit. At this time, the latch circuit 6 has been reset but not set, so its output, and therefore the SA signal, is "L", and the multiplexer 13 receives the temperature value from the storage section 11 (in this case , the previous temperature measurement value N _x ′) is selected. However, display decoder 14 is preset and therefore does not accept the output of multiplexer 13.

The switch 1 is kept closed and its _Qo output is inverted every time the counter 4 counts n, but the latch circuit 5 is kept in the reset state, and therefore the SA from the latch circuit 6 is The signal is kept at "L", and the GRST2 signal is also kept at "L".

Now, if switch 1 is opened before counter 4 counts 16n (operation completed), counter 4 and latch circuit 5 are reset, and the output of latch circuit 5 is inverted from "L" to "H". . However, since this has no effect on the counter 7, the GRST1 signal is held at "L" as it is, and GRST2 is also held at "L". Also, the latch circuit 6 is reset before being set, and its Q output is held at "L" and sent to the multiplexer 1.
3 selects the temperature measurement value N _x ' from the storage unit 11 as is.

On the other hand, counter 8 counts the clock from counter 3. Then, when a predetermined number l is counted, the Ql output is inverted from "L" to "H",
Although the rising edge of this Ql output is detected by the control section 9, the control section 9 does not send a signal to the temperature measurement section 10. Furthermore, when the counter 8 continues counting and the count value reaches 2l, the Ql output is inverted from "H" to "L", and the _Qn output is inverted from "L" to "H". The latch circuit 16 is set at the rising edge of this Q _n output, and its output is inverted from "H" to "L". The falling edge of this output is detected by the falling edge detection section 17 and
A signal is generated, which resets the memory 11. As a result, in the storage unit 11, the previous temperature measurement value N _x ' is erased and the value 0 is held.

Furthermore, since the latch circuit 16 is set and its output is inverted from "H" to "L", the D _i PR signal from the inverter 28 is inverted from "H" to "L", and the display decoder 14 is inverted from "H" to "L". Preset is canceled.

Therefore, the display decoder 14 uses the multiplexer 1
In this case, the multiplexer 13 selects the temperature value from the storage unit 11, and this temperature value is 0, so the out-of-measurement-range detection means in the multiplexer 13 decodes the temperature value from the storage unit 11. Vessel 1
5 is displayed as "L0℃".

This state continues until switch 1 is operated again. Meanwhile, the counter 8 continues counting operation, and when the count value reaches 3l, its QI output is reversed from "H" to "L", and the control section 9 detects this reversal and sends a signal to the temperature measurement section 10. send.

On the other hand, the temperature measurement section 10 has completed the first temperature measurement immediately before the rising edge of the Ql output of the counter 8, and upon receiving the signal from the control section 9, reads out the temperature measurement value from the storage section 11. Compare with the current temperature value N ₁ obtained by the first temperature measurement. In this case, the read temperature value is 0 and the current temperature value
Since N ₁ is larger, the temperature measurement unit 10 sends the MAX·φ signal to the storage unit 11 and stores the current temperature measurement value N ₁ in the storage unit 1.
Write to 1. As a result, the display 15 displays a numerical value "T ₁ °C" corresponding to this current temperature measurement value N ₁ .

Furthermore, the counter 8 continues to count, and when the count value is 4l, its Qn output is inverted from "H" to "L", and when the count value is 5l, its Qn output is inverted from "L" to "H". At the rising edge of this Qn output, the temperature measuring section 10 returns the current temperature value N ₂ obtained just before.
and the measured temperature value N ₁ held in the storage section 11 , and if the current measured temperature value N ₂ is larger, it is rewritten in the storage section 11 to the current measured temperature value N ₂ . For this,
The display 15 displays a numerical value "T ₂ °C" corresponding to this current temperature measurement value N ₂ .

In this way, counter 8 continues to count and 2l
At the rising edge of the Ql output for each count, the temperature measurement section 10 compares the temperature measurement value with the temperature measurement value held in the storage section 11, and if the current temperature measurement value is larger, the temperature measurement section 10 compares the temperature measurement value with the temperature measurement value held in the storage section 11. to rewrite to the current temperature value. Therefore, after the memory section 11 is reset, the largest temperature value among the temperature measurements obtained so far is held, and during a period when the temperature is rising, the memory section 11 stores the maximum value for each temperature measurement. The measured temperature value held in the display 15 is updated, and the numerical value displayed on the display 15 is also updated each time.

Also, during this time, the subtraction unit 31 outputs difference data between the temperature measurement value held in the storage unit 11 and the previous temperature measurement value N _x ' held in the storage unit 12. When not in use, the storage unit 11 holds the previous temperature measurement value N _x ′, and the storage unit 12 holds the temperature measurement value N _x ″ before the previous time, and at this time, the subtraction unit 31 Difference data of N _x ′ and N _x ″ is output. The difference value S _ub at this time is |N _x ′−N _x ″|=ΔN _x ′, and if N _x ′<N _x ″, the code data S _io is positive.

The previous temperature measurement value N _x ' held in the storage unit 11 by the MEMO·φ signal is written into the storage unit 12, and the difference value S _ub from the subtraction unit 31 becomes 0. The code data S _io at this time is positive. next,
When the storage section 11 is reset by the MAX.R signal, the difference value S _ub from the subtraction section 31 becomes N _x ', and the code data S _io is also positive. continue,
The measured temperature value N ₁ from the temperature measurement unit 10 is stored in the storage unit 11,
As N ₂ , ... are written in sequence, the difference value S _ub from the subtraction unit 31 becomes |N _x ′−N ₁ |
=ΔN ₁ , |N _x ′−N ₂ |=ΔN ₂ , ..., and the current temperature measurement values N ₁ , N ₂ ... written in the storage unit 11 do not exceed the previous temperature measurement value N _x ′ As long as the sign data S _io remains positive.

In this way, as the current measured temperature value held in the storage section 11 changes, the difference data from the subtraction section 31 changes, but the Q output of the latch circuit 6 becomes "L".
The difference data output from the subtraction unit 31 is not written to the storage unit 32 unless the subtraction unit 31 is inverted from “H” to “H”.
Therefore, at this time, the storage section 32 holds the difference data from the previous or previous use. In FIG. 2a, the difference value SUB of this difference data is set to ΔN _o ', and the sign data SIN is set to be positive.

Thereafter, when the switch 1 is operated to close, the counter 4 and the latch circuit 5 are reset, and as explained earlier, the output of the latch circuit 5 is inverted from "H" to "L", and the counter 7 is 1
The Q output changes from “H” to “L”.
The GRST1 signal is inverted from "L" to "H".

However, since the output of the latch circuit 5 is "L", the GRST2 signal is maintained at "L". Furthermore, since the input of the NAND gate 19 on the switch 1 side is "L", the MCK/N signal is also held at "L".

The switch 1 continues to be closed, and when the counter 4 finally counts 16n, its Q output is inverted from "L" to "L". Therefore, since the GRST1 signal is "H", the output G4 of the NAND gate 22
is inverted from "H" to "L", and the output of the inverter 26 is inverted from "L" to "H", and the latch circuit 6 is reset by this inversion. For this reason,
The Q output of the latch circuit 6 is inverted from "L" to "H", and at its rising edge, the subtraction section 31 is stored in the storage section 32.
The difference data from is written, and the difference value SUB of the difference data and code data SIN are supplied to the multiplexer 13. Here, the Q of the latch circuit 6 is
If the current temperature value held in the storage unit 11 at the time of the output fall is _No , the difference value SUB read from the storage unit 32 is |N _o ′−N _o |=ΔN _o , and N _x ′
〈N _o , the sign data SIN is negative.

At the same time, the SA signal becomes "H", so the multiplexer 13 selects the difference data from the storage section 32. The display decoder 14 decodes this, and therefore the display 15 displays a display value "ΔT _o °C" corresponding to ΔN _o of this difference data and a sign "-" corresponding to the sign data. Ru.

On the other hand, the counter 7 is preset at the rising edge of the Q output of the latch circuit 6, and the Q output is inverted from "L" to "H" and the GRST1 signal goes "H".
to "L". Therefore, the output G4 of the NAND gate 22 becomes "H".

After that, when switch 1 is opened, counter 4 and latch circuit 5 are reset, and the output of latch circuit 5 is inverted from "L" to "H", but counter 7
is not affected by this, the GRST1 signal remains "L", and therefore the GRST2 signal also remains "L", and each circuit is maintained in the operating state, and the display 15 shows the displayed value " ΔT _o °C" and the sign "-" continue to be displayed. During this time, if the current temperature value from temperature measurement value 10 increases, the current temperature value is rewritten in the storage unit 11, and therefore the subtraction unit 3
The difference data from 1 also changes.

Next, in FIG. 2b, when the switch 1 is closed again, the counter 4 and the latch circuit 5 are reset, and the output of the latch circuit 5 is inverted from "H" to "L". Along with this, the counter 7 counts by 1 and the GRST1 signal is inverted from "L" to "H". However, since the output of latch circuit 5 is "L", the GRST2 signal is "L".
The latch circuit 6 is not reset and the display 15 shows the displayed value "ΔT _o °C" and the sign "-".
is displayed.

Therefore, when switch 1 is opened, the MCK/N signal is inverted from "L" to "H" and oscillator 2, counter 3, and falling edge detector 18 are reset, and counter 4 and latch circuit 5 are also reset. , the output of the latch circuit 5 is inverted from "L" to "H". Since counter 7 does not count on the rising edge of this output, GRST
The GRST1 signal remains at "H", and the GRST2 signal is inverted from "L" to "H".

As a result, the latch circuit 6 is reset and its Q output is inverted from "H" to "H".
4. Latch circuit 16 and falling edge detector 1
7 is also reset and the operation of the temperature measuring section 10 is stopped.
The display 15 displays blank.

The operation period (closed period) of switch 1 to stop the operation of each part is 16n of counter 4.
It may be less than or greater than the counting period. This is because once the latch circuit 6 is set, the GRST2 signal becomes "H" (this is
(deactivates each part) unless reset.
This is because it will not be set again, and therefore the counter 7 whose Q output is "L" will not be preset.

In this embodiment, the duration of the operation of the switch 1 to start the operation may be longer or shorter than the 16n count period of the counter 4, and the display is displayed according to the temperature measurement value from the storage unit 11. When switch 1 is closed for a period shorter than the 16n count period of counter 4 while performing step 15,
All operations stop.

To briefly explain this point using the timing chart in Fig. 3, when switch 1 is closed with all the circuits reset, latch circuit 5 is set as explained earlier. The output is inverted from “H” to “L”,
GRST1 signal and GRST2 signal are both “H”
When the latch circuit 6 is released from the reset state, the temperature measurement section 10 starts operating, and all segments of the display 15 are lit.
At this time, the Q output of the counter 4 is "L" and the G4 signal from the NAND gate 22 is "H".

Furthermore, the previous temperature measurement value N _x ' is written into the storage unit 12 by the MEMO·φ signal generated by the engine when the GRST2 signal falls.

When the switch 1 is opened and closed, and then the counter 4 counts 16n, its Q output inverts from "L" to "H", but since the GRST1 signal is "L", the G4 from the NAND gate 22
The signal remains at "H" and the latch circuit 6 is not set. Therefore, its Q output is “L”
Therefore, the multiplexer 13 continues to select the current measured temperature value from the storage section 11. For this,
On the display 15, "L0°C" is displayed after the lighting period of all segments has elapsed, and then the storage unit 1
Displays the display value according to the temperature measurement value from 1.

Even when the switch 1 is opened and the counter 4 and the latch circuit 5 are reset, this state is maintained as it is, and the display 15 displays a display according to the temperature measurement value from the storage section 11. Then, the subtraction section 31
Now, as explained earlier, the difference data changes as the temperature value in the storage section 11 changes, but since the latch circuit 6 is not set, the storage section 32 cannot write the difference data from the subtraction section 31. Therefore, the storage unit 32 retains the difference data from the previous or previous use.

Next, when the switch 1 is closed and the counter 4 and the latch circuit 5 are reset, the counter 7 counts by 1 as the output of the latch circuit 5 is reversed from "H" to "L". , GRST1
The signal is inverted from "L" to "H".

Then, when the switch 1 is closed for more than the 16n count period of the counter 4, the display value corresponding to the difference data in the storage section 32 is displayed on the display 15 as explained earlier in FIG. 4 is
When switch 1 is opened before counting 16n, the output of latch circuit 5 is inverted from "L" to "H".
Furthermore, since the latch circuit 6 is not set, the counter 7 is not preset, and the GRST1 signal is held at "H" as it is.

Therefore, as the output of the latch circuit 5 is inverted from "L" to "H", the GRST2 signal is inverted from "L" to "H", the operation of the temperature measuring section 10 is stopped, and the latch circuit is inverted from "L" to "H". 6 is reset. Furthermore, when switch 1 is opened,
The MCK/N signal is inverted from “L” to “H”,
It goes without saying that the oscillator 2, counter 3 and falling edge detector 18 are reset.

As described above, in this embodiment, if the switch 1 is operated for a period shorter than the 16n count period of the counter 4 after the temperature measuring section 10 starts operating, all operations are stopped, but if the switch 1 is operated for a period longer than the 16n count period, When switch 1 is operated, the display according to the difference data is performed until the next operation of switch 1.

As described above, in this embodiment, when the current temperature value obtained by the temperature measurement section 10 increases sequentially, the display value on the display 15 is updated sequentially, and the current temperature measurement value is If switch 1 is closed for more than 16n counts of counter 4 while the display is being performed according to the value, the maximum current temperature value and the previous temperature measurement until this switch 1 operation is performed will be displayed. Display is performed according to the difference data from the value. Therefore, the display 1 according to the temperature measurement value from the storage section 11
When the displayed value at step 5 no longer changes, it means that the measured value represents the temperature to be measured (for example, body temperature).
After such a display has been made, by keeping the switch 1 in the closed state for a period of 16n counts of the counter 4 or more, it is possible to directly know the change in the temperature to be measured between the previous measurement and the current measurement. .

FIG. 4 is a block diagram showing another embodiment of the temperature measuring device according to the present invention, in which parts corresponding to those in FIG. 1 are given the same reference numerals and redundant explanation will be omitted.

In the embodiment explained in FIG. 1 above, the difference data outputted by the subtraction section 31 is once written in the storage section 32, and then read out and supplied to the multiplexer 13. However, in this embodiment shown in FIG. Then, the difference data from the subtraction unit 31 is directly sent to the multiplexer 1.
3.

Therefore, in this embodiment, as shown in the timing charts of FIGS. If the state is longer than the 16n count period of
A display value corresponding to the difference data from 1 is displayed. In this case, since this difference data is obtained by subtracting the temperature measurement value from the storage unit 11 and the previous temperature measurement value N _x ' from the storage unit 12, the temperature measurement value from the temperature measurement unit 1
When the decremented temperature values obtained at 0 are increasing sequentially, the temperature values held in the storage section 11 are increasing sequentially, so the displayed values corresponding to the difference data displayed on the display 15 are also updated sequentially. Ru.

When the current temperature value obtained from the temperature measurement unit 10 reaches the maximum value (that is, the temperature value representing the temperature to be measured such as body temperature), the temperature measurement value held in the storage unit 11 will not change. Therefore, display 15
The displayed value will be constant. This represents the difference between the previous measurement result and the current measurement result.

Other operations are similar to the embodiment shown in FIG.

Note that in the embodiment shown in FIG.
If you do not operate the switch 1 until the displayed value corresponding to the temperature measurement value from the storage unit 11 displayed on the screen does not change, the temperature to be measured cannot be accurately determined, as in the embodiment shown in FIG. can be measured and
In addition, although the difference between the previous measurement result and the current measurement result can be accurately obtained, even if the switch 1 is operated too quickly (i.e., when the displayed value on the display 15 is changing, Even if you operate 1),
The difference between the previous measurement result and the current measurement result can be accurately obtained.

The embodiments of this invention have been described above, and these can not only start and stop the temperature measurement operation by operating a single switch, but also display the current temperature value and the previous temperature measurement. It is possible to switch the display according to the difference between the current temperature measurement value and the current temperature measurement value, and with simple operations, it is possible to accurately and easily understand the current measurement result and the change in the target temperature. Even if you use it, it will not malfunction.

Furthermore, at the start of operation, all segments of the display 15 are lit, and then "L0°C" is displayed, so that it is possible to check whether the display section is operating normally or not, and also to make measurements. It can be confirmed that the temperature is being warmed, improving the reliability of the displayed content.

Furthermore, if the temperature value is outside the measurement range, fixed numbers, symbols, patterns, etc. are displayed.
It is possible to prevent the user from making unnecessary decisions by displaying meaningless temperatures outside the measurement range.

In the above embodiment, if the period during which the counter 8 counts l is approximately 0.7 seconds, the display 15
The lighting period for all segments is approximately 1.4 seconds, which is sufficient to recognize that all segments are lit. However, these numerical values and the specific numerical values used in the previous explanation are merely examples, and the present invention is not limited to these numerical values.

Further, in the above embodiment, the previous temperature measurement value _N
A rising edge detection section is used instead of 8, and the GRST2 signal is delayed and supplied to the reset terminal of this section, and the falling edge of the GRST2 signal is used.
MEMO・φ signal is formed, and the temperature measuring section 1
Upon completion of the 0 operation, the temperature measurement value N _x held in the storage section 11 can be written into the storage section 12 and used as the previous temperature measurement value for the next temperature measurement.

〔Effect of the invention〕

As explained above, according to the present invention, not only can the operation be started or stopped by operating a single switch, but also the duration of operation of the switch can be extended even during temperature measurement operation. Even with a simple operation, it is possible to select the display according to the difference between the previous temperature value and the current temperature value instead of the display according to the current temperature value. In addition to being able to measure temperature, it is also possible to directly know changes in the target temperature, and it is possible to obtain excellent effects that are not available in the prior art.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the temperature measuring device according to the present invention, FIGS. 2a, b, and 3 are timing charts for explaining the operation of FIG. 1, and FIG. A block diagram showing another embodiment of the temperature measuring device, and FIGS. 5a and 5b are timing charts for explaining the operation of FIG. 4. 1...Switch, 4...Counter, 5, 6...
Latch circuit, 7, 8...Counter, 10...Temperature measurement section, 11, 12...Storage section, 13...Multiplexer, 15...Display device, 31...Subtraction section, 32...
...Memory Department.

Claims (1)

[Claims] 1. A switch that can be operated from the outside, a first determination section that determines the open/close operation state of the switch, a temperature measurement section that starts operating in response to the output of the first determination section, and a measurement of the temperature measurement section. a first storage section that holds data, a second storage section into which the measurement data held in the first storage section is written when the temperature measurement section starts or ends its operation; a second determining section that determines the length of the operation duration of the switch that is operated after the operation of the temperature measuring section; and a selection section that selects whether to continue or stop the operation of the temperature measuring section according to the output of the second determining section. a subtraction unit that outputs difference data between the measurement data held in the first storage unit and the measurement data held in the second storage unit; a multiplexer that selects either the measurement data read out from the first storage section or the difference data obtained by the subtraction section; and a display section that displays a display according to the data selected by the multiplexer. In preparation, after the temperature measurement unit starts operating, the first storage unit holds current measurement data by the temperature measurement unit, and the second storage unit holds previous measurement data by the temperature measurement unit. display on the display unit according to the current measurement data,
The device is characterized in that switching to a display according to the difference data and stopping the operation of the temperature measurement unit can be selected depending on the duration of operation of the switch after activation of the temperature measurement unit. Measuring instrument.