JPH0544969B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermometer and a temperature measuring device for equipment observation and maintenance.
This invention relates to an electronic temperature measuring device that has a function that allows you to check the previous temperature measurement result.

[Conventional technology]

This type of electronic 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, unlike mercury thermometers, it does not have a function that allows you to check the previous temperature measurement results before starting the temperature measurement operation, so it is necessary to write down the previous temperature measurement value after each temperature measurement. It was complicated.

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. 287-293
(see page).

[Problem that the invention seeks to solve]

In the above conventional technology, in addition to the switch for starting temperature measurement, a dedicated memory switch is provided for reading the temperature measurement results from the memory section, which makes the circuit configuration complicated and the entire device Since it is large in size and requires two switches to be operated separately, the operation is complicated and easy to operate incorrectly, and it is not suitable for home use mainly for women and girls.

[Means for solving problems]

This invention was made in view of the above circumstances, and includes a single switch that can be operated from the outside, and when the switch is operated, the previous temperature measurement value within a predetermined measurement range is displayed. When the switch is released, the temperature measuring section starts measuring the temperature, and the temperature value obtained from the temperature measuring section is displayed. This simplifies the circuit configuration and improves the overall efficiency of the device. In addition to realizing miniaturization, the operation is simplified to make it easier to handle.

〔Example〕

Embodiments of the present invention will be described below with reference to the 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 is a counter, 4 is a NAND gate, 5 is a counter, 6 is an RS type latch circuit, 7 is a counter,
8 is an inverter, 9 is a counter, 10 is a control unit,
11 is a temperature measurement section, 12 is a storage section, 13 is a measurement range outside detection section, 14 is a display decoder, 15 is a display device, 1
6 is a NAND gate, 17 is an RS type latch circuit,
Reference numerals 18 and 19 designate falling edge detection units, 20 a measurement range detection unit, 21 a storage unit, 22 a multiplexer, 23 to 27 inverters, and 28 a NAND gate.

In the figure, an oscillator 2, counters 3, 5,
7, 9, latch circuits 6, 17, control section 10, temperature measurement section 11, display decoder 14, falling edge detection sections 18, 19, respectively, when the signal supplied to the reset terminal R is at a high level (hereinafter referred to as " H”),
It is in a reset state.

The switch 1 is a normally open switch operated from the outside, such as a push button switch. When the switch 1 is not operated, one input of the NAND gate 4 is "H", and the counter 5 is The latch circuit 6 is reset with its reset input set to "H".

The oscillator 2 is a CR oscillator or a crystal oscillator, and generates a reference clock MCK. This reference clock MCK is frequency-divided by a counter 3 to a predetermined frequency and is supplied to counters 5 and 9 and a display decoder 14. The oscillator 2 and the counter 3 are switched between operating and non-operating states by an MCK·N signal obtained by inverting the output signal of the NAND gate 4 with an inverter 8.

The counter 5 and the latch circuit 6 constitute a determining section for determining whether the switch 1 has been operated. In this determination section, the counter 5 prevents malfunctions due to the chatter of the switch 1. If the switch 1 is operated and remains closed for a predetermined period (approximately 0.1 seconds) or more, the counter 5 overflows and its Q output decreases. Level (hereinafter referred to as "L")
to "H". Further, the latch circuit 6 is set at the rising edge of the Q output of the counter 5,
At the same time, the output is inverted from "H" to "L". The counter 5 and the latch circuit 6 are in a 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", and each time switch 1 is opened, its output is inverted from "L" to "H".

Counter 7 is a 1-bit binary counter that counts by one at the falling edge of the output of latch circuit 6, and its Q output is inverted each time it counts. The Q output of the counter 7 is inverted by the inverter 23, and is supplied as the GRST1 signal to the display decoder 14 and the reset terminal R of the falling edge detector 18, as well as to the NAND gate 4. When the GRST1 signal is "H", these circuits are in a reset state, and the display 15 is blank (ie, nothing is displayed). Furthermore, when the GRST1 signal becomes "L", the reset of these circuits is released at the same time, and the display 15 displays predetermined data.

The Q output of the counter 7 is supplied to the NAND gate 28 together with the output of the latch circuit 6, and GRST
Two signals are formed. This GRST2 signal is transmitted to the counter 9, the control section 10, the temperature measurement section 11, and the latch circuit 1.
7 and the reset terminal R of the falling edge detector 18, and is also inverted by the inverter 24 and supplied to the NAND gate 16.

Counter 9 further divides the clock from counter 3. The Q _l output with a predetermined frequency division ratio is supplied to the control section 10 and controls the timing of temperature measurement in the temperature measurement section 11 . The Q _n output with a frequency division ratio twice that of the Q _l output is supplied to the latch circuit 17 as a set input. The latch circuit 17 controls the counter 9 after the reset is released.
Set on the first rising edge of the Q _n output, which inverts the output from "H" to "L". This output is supplied to the falling edge detector 18 which has already been released from reset, and a MAX.R signal representing the falling edge is formed. This MAX・R
The signal is stored in a storage section 12 consisting of a D-type flip-flop.
and erase the previous temperature measurement value that has been held so far. The output of the latch circuit 17 is also supplied to the NAND gate 16.

When the reset is released, the temperature measuring section 11 measures the temperature once every cycle of the _Ql output of the counter 9, and completes the temperature measurement immediately before each _Ql output.
Then, in synchronization with the rising edge of the Q _l output, the temperature measurement value obtained at that time is compared with the temperature measurement value held in the storage unit 12, and the temperature measurement value obtained at that time (hereinafter, current When the measured temperature value) is large, the temperature measuring section 11 generates a MAX·φ signal, and the storage section 12
The current measured temperature value is written in place of the previously held temperature value. Therefore, the storage unit 12 stores the maximum temperature value among the temperature values obtained so far after the reset of the temperature measurement unit 11 is released.

The temperature value held in the storage unit 12 is read out and sent to the out-of-measurement-range detection unit 13 and the in-measurement-range detection unit 2.
0 and 0. When the temperature measurement value read from the storage unit 12 is outside the predetermined measurement range, the out-of-measurement-range detection unit 13 displays a fixed numerical value in place of the temperature measurement value in order to display this on the display 15. Data representing symbols, patterns, etc. is supplied to the display decoder 14 via the multiplexer 22. Further, the measurement range detection unit 20 detects whether the temperature value read from the storage unit 12 is within the predetermined measurement range, and only when it is within the predetermined measurement range,
A MEM·φ signal is generated, and the temperature measurement value read from the storage unit 12 is written in the storage unit 21 in place of the temperature measurement value held so far. This operation of the measurement range detecting section 20 is performed at the time when the output of the latch circuit 6 falls. That is, the falling edge of the output of the latch circuit 6 is detected by the falling edge detection section 19, and the "H"
" pulse is supplied to the inverter 27, and an EN signal that is "L" during this "H" pulse period is obtained. This EN signal is supplied to the measurement range detection section 20, but this EN signal " During the L'' period, the measurement range detection section 20 performs the above operation.

By the way, the EN signal almost coincides with the falling point of the latch circuit 6, but the MAX.R signal lags behind this by about the time until the _Qn output of the counter 9 rises. Therefore, the previous temperature measurement value within the predetermined measurement range that was held in the storage section 12 is written into the storage section 21 . It should be noted that when this previous temperature measurement value is outside the predetermined measurement range, the memory contents of the storage unit 21 are not rewritten, and the maximum temperature measurement value from the previous time or before is held as is.

Here, the above prescribed measurement range is 35.0℃~42.0℃.
℃. The out-of-measurement-range detection section 13 has a storage section 12.
Outputs predetermined data so that when the temperature value read from the temperature reading is less than 35.0°C, "LO°C" is displayed on the display 15, and when it exceeds 42.0°C, "HI°C" is displayed on the display 15. do.

The multiplexer 22, the display decoder 14, and the display 15 constitute a display section that switches between and displays the output of the out-of-measurement-range detection section 13 and the temperature measurement value from the storage section 21.

When the SA signal obtained by inverting the output of the latch circuit 6 with the inverter 26 is "H", the multiplexer 22 selects the input A, which is the temperature value read out from the storage section 21, and sends it to the display decoder 1.
4, but when the SA signal is “L”,
The output of the out-of-measurement-range detection unit 13 is selected and supplied to the display decoder 14.

The display decoder 14 decodes the output of the multiplexer 22 after being reset by the GRST1 signal becoming "L", and displays the display 15.
The above display is performed with the “H” level supplied from the inverter 25 to the preset terminal PR.
Display 1 is preset by the DisPR signal of
5 is supplied with a signal that causes all its segments to light up.

Next, the operation of this embodiment will be explained using FIGS. 2 and 3 showing the operation timing of each part.

Even when the device is not in use, the storage unit 12 retains the previous temperature measurement value. When a power source (not shown) is turned on, the display 15 is activated. At the same time, the reset of the counter 7 is released, but its Q output is "L" and the GRST1 signal is "H". Therefore, the display decoder 14 is in a reset state, the display 15 is showing a blank display, and the falling edge detector 19 is also in a reset state. Also, since the input of the switch 1 side of the NAND gate 4 is "H" and the other input, the GRST1 signal, is also "H", the MCK/N signal obtained by inverting the output of this NAND gate 4 with the inverter 8 is "H", and the oscillator 2 and counter 3 are in the reset state.

Furthermore, since the output of the latch circuit 6 is "H" and the Q output of the counter 7 is "L", GRST2
The signal is “H”, and the counter 9, control unit 10,
The temperature measurement section 11, the latch circuit 17, and the falling edge detection section 18 are also in the reset state. “H”
The GRST2 signal is inverted by the inverter 24 and supplied to the NAND gate 16, and furthermore, the latch circuit 1
Since the "H" output of No. 7 is also supplied to the NAND gate 16, the DisPR signal obtained by inverting the output of this NAND gate 16 with the inverter 22 is "L".
It is.

In such a state, when switch 1 is closed,
The reset of the counter 5 and the latch circuit 6 is released, and the input on the switch 1 side of the NAND gate 4 is inverted from "H" to "L", so the MCK.N
The signal becomes "L" and the oscillator 2 and counter 3 are also released from reset. Therefore, the oscillator 2 generates the reference clock MCK, which is frequency-divided by the counter 3.

Counter 5 counts the clock output from counter 3, but if switch 1 is closed for more than about 0.1 seconds, counter 5 overflows.
The Q output is inverted from "L" to "H". This inversion sets the latch circuit 6, and its output is inverted from "H" to "L". At the falling edge of this output, the counter 7 counts by 1, its Q output is inverted from "L" to "H", and therefore the GRST1 signal is inverted from "H" to "L". As a result, the display decoder 14 is released from reset.

On the other hand, the output of the latch circuit 6 is supplied to a falling edge detection section 19, and an "H" pulse representing the falling edge is generated. This pulse is supplied to the inverter 27, and the EN signal becomes "L" during this pulse period. During the “L” period of this EN signal, the measurement range detection unit 20 takes in the previous temperature measurement value N _x ′ held in the storage unit 12 . Then, when this previous temperature measurement value N _x ' is within the predetermined measurement range, as shown in FIG.
generates the MEM·φ signal, and writes the previous temperature measurement value N _x ′ in place of the previous temperature measurement value N _x ″ that has been held so far in the memory unit 21 .

On the other hand, when the previous temperature measurement value N _x ' is outside the predetermined measurement range, as shown in FIG. The storage unit 21 retains the temperature measurement values from the time before or before.

Furthermore, the output of the latch circuit 6 is connected to the inverter 2.
The SA signal obtained by inverting at step 6 goes from “L” to “H”
Therefore, the multiplexer 22 selects the A input and selects the previous temperature measurement value read from the storage unit 21.
N _x ′ (Figure 2) or previous temperature measurement N _x ″
(FIG. 3) is sent to the display decoder 14. At this time,
Since the GRST2 signal obtained from the NAND gate 28 is "H" and the latch circuit 17 is in the reset state and its output is "H", the DisPR signal obtained from the inverter 25 is "L".
Display decoder 14 is not preset. As a result, display decoder 14 outputs multiplexer 22
The temperature measurement value N _x ′ or N _x ″ supplied from the controller is decoded, and the corresponding numerical value “T _x ′°C” or “T _x ″°C” is displayed on the display 15.

After that, when switch 1 is opened, counter 5
The latch circuit 6 is reset again, and the latch circuit 6 is inverted from "L" to "H".
Counter 7 does not count this, so GRST
1 signal remains "L", and even if the input on the switch 1 side of NAND gate 4 becomes "H", the MCK signal remains "L".
The ON signal is "L". Therefore, oscillator 2
and counter 3 continue to operate.

On the other hand, the output of the latch circuit 6 becomes "H",
Since the Q output of the counter 7 is "H", the GRST2 signal obtained from the NAND gate 28 becomes "L", and the counter 9 is released from reset and starts counting the clock from the counter 3, and the control section 10, The temperature control section 11, latch circuit 17, and falling edge detection section 18 are also released from reset.

At the same time, the output of the latch circuit 6 goes “L”.
Inverter 2 is inverted from “H” to “H”.
The SA signal obtained from 6 is inverted from "H" to "L", and multiplexer 22 selects the B input.
However, as the GRST2 signal is inverted from "H" to "L", the input on the inverter 24 side of the NAND gate 16 becomes "H", and the input on the other latch circuit 18 side is also "H", so the DisPR signal is inverted from "L" to "H", and the display decoder 14 is preset. As a result, the display decoder 14
is inhibited from accepting data from multiplexer 22 and all segments of display 15 are illuminated.

By lighting all segments of the display 15 in this manner, it is possible to confirm that the display decoder 14 and the display 15 are operating normally before starting temperature measurement.

When the counter 9 continues to count and reaches a predetermined number n, the Q _l output is inverted from “L” to “H”, and then continues counting by n and the count value changes.
2n, the Q _l output is inverted from "H" to "L" and the Q _n output is inverted from "L" to "H". The latch circuit 17 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 18 and
A signal is generated, which resets the memory 12. As a result, in the storage unit 12, the previous temperature measurement value N _x ' is erased and the value 0 is held.

Furthermore, since the output of the latch circuit 17 becomes "L", the output of the NAND gate 16 becomes "H".
Therefore, the DisPR signal becomes "L" and the preset of the display decoder 14 is released.
As a result, the temperature value read out from the storage unit 12 is supplied to the display decoder 14 via the out-of-measurement-range detection unit 13 and the multiplexer 22, but in this case, this temperature value is 0 and is outside the measurement range. That is, since the temperature is less than 35.0° C., the out-of-measurement-range detection unit 13 supplies data representing “LO° C.” to the display decoder 14, and therefore, the display 15 displays this.

When the count value of the counter 9 reaches 3n, the _Ql output is inverted from "L" to "H", and the control section 10 detects this inversion and sends a signal to the temperature measuring section 11.

On the other hand, in the temperature measurement section 11, the first temperature measurement has been completed immediately before the rising edge of the Q _l output above the counter 9, and upon receiving a signal from the control section 10, the storage section 1
The measured temperature value is read from 2 and compared with the current measured temperature value _N1 . In this case, since the read temperature value is 0, the current temperature measurement value _N1 is larger. ₁ is written into the storage unit 12. As a result, "T ₁ °C" for the temperature measurement value N ₁ is displayed on the display 15.

Note that the period during which the counter 9 counts n is set to approximately 0.7 seconds here, so the Q _l output has a period of approximately 1.4 seconds, and the Q _n output has a period of approximately 2.8 seconds. Therefore, the previous temperature measurement value T _x ′ (second
(Fig. 3) or the display period of the previous temperature value _T It is 0.7 seconds.

Furthermore, the counter 9 continues counting, and when the count value reaches 4n, the Q _l output inverts from "H" to "L", and then when the count value reaches 5n, the Q _l output changes from "L" to "H". to be reversed. Along with this,
In the temperature measuring section 11, the current temperature value obtained immediately before
N ₂ and the temperature measurement value N ₁ held in the storage unit 12 are compared, and if the current temperature measurement value N ₂ is larger, it is rewritten in the storage unit 12 to the current temperature measurement value N ₂ . Therefore, the display 15 displays the display value "T ₂ °C" for this temperature measurement value N ₂ .

In this way, unless the switch 1 is operated, the counter 9 continues counting, and at the rising edge of the _Ql output every 2n counts for approximately 1.4 seconds, the current temperature value and the temperature value held in the storage unit 12 are calculated. When the current measured temperature value is larger, the storage unit 12
can be rewritten to the current temperature value. Therefore, the maximum temperature measured so far is displayed on the display 15, and the displayed value is updated as the temperature rises.

Incidentally, the Q _n output of the counter 9 rises every 4n counts, but the latch circuit 17 is kept in the set state and the temperature measuring operation described above is continued.

Next, when switch 1 is closed, counter 3 and latch circuit 6 are reset. In this case too
Since the MCK·N signal is held at "L", the oscillator 2 and counter 3 are in operation. Therefore,
The counter 5 counts the clock from the counter 3, and when it overflows after about 0.1 seconds, the latch circuit 6 is set and its output changes from "H" to "L".
to be reversed. As a result, the Q output of the counter 7 is inverted from "H" to "L", and the GRST1 signal becomes "L".
to "H". Therefore, the display decoder 14 is reset and the display 15 displays blank.

At the same time, the GRST2 signal is inverted from "L" to "H", and the counter 9, control section 10, temperature measurement section 11, latch circuit 17 and falling edge detection section 18 are reset. In this case, MAX・R
Since no signal is generated, the maximum temperature measurement value N _x up to now is held in the storage unit 12 as is. This temperature measurement value N _x becomes the previous temperature measurement value at the time of the next temperature measurement.

Furthermore, the GRSR1 signal that is one input of the NAND gate 4 is "H", and the other input on the switch 1 side is "L" because the switch 1 is closed, and the MCK/N signal is "H". However, when the switch 1 is opened, both inputs of the NAND gate 4 become "H", and therefore the MCK/N signal becomes "H" and the oscillator 2
and the counter 3 becomes inactive. of course,
The counter 5 and latch circuit 6 are also reset.

In this way, the temperature measurement operation is completed and the system is stopped.

As described above, in this embodiment, by operating a single switch 1, the previous temperature measurement value or previous temperature measurement value and the maximum current temperature measurement value are switched and displayed. This makes the operation very easy, and these switching displays are
By closing the switch 1, the previous temperature measurement value or the previous temperature measurement value is displayed, and then by opening the switch 1, the current temperature measurement value is switched and displayed. The temperature measurement value or the past temperature measurement value of the previous temperature measurement value can be viewed at any time and can be confirmed with certainty. Therefore, it is possible to prevent erroneous operations and failure to check past temperature measurements. Further, since past temperature measurements are not displayed incorrectly or meaningless temperatures outside the predetermined measurement range, there is no possibility of confusion for the user. Therefore, when used at home, even women and girls can easily handle it.

Furthermore, before the start of temperature measurement, the storage section 12 is reset to 0, and as a result, the display 15
``LO℃'' is displayed, but by this,
You can confirm that temperature measurement has started.

Furthermore, by lighting all segments of the display 15 before starting temperature measurement, the display decoder 1
4 and the display 15 can be confirmed to operate normally.

Although specific numerical values are shown in describing the above embodiments, these are merely examples, and the present invention is not limited by these values.

The switch 1 may be of various types, as long as it can be opened and closed from the outside, such as a push-button type, a slide type, or a reed switch provided inside the main body case (not shown) and operated from the outside using a sugnet or the like. be able to.

In addition, “LO” indicates a temperature value outside the measurement range.
℃", "HI℃", etc., are stored in the display decoder 14, and when the temperature measurement value from the multiplexer 22 is outside the measurement range, the display decoder 14 displays the symbols, patterns, etc. It can also be configured to be supplied to a container 15. In this case, the out-of-measurement-range detection section 13 described above becomes unnecessary.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to switch between a past temperature measurement value and a current temperature measurement value and to start and stop the temperature measurement operation by operating a single switch. Moreover, one of the switches
The device switches between the previous temperature measurement value and the current temperature measurement value and performs the temperature measurement operation by multiple operations.The operation is extremely simplified and handling is extremely easy. Since the value within the predetermined measurement range is always displayed, there is no confusion during use, and furthermore, the excellent effect of being simple in structure and miniaturization can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the temperature measuring device according to the present invention, and FIGS. 2 and 3 are timing charts for explaining the operation of FIG. 1. 1...Switch, 5...Counter, 6...Latch circuit, 9...Counter, 10...Control unit, 11
... Temperature measuring section, 12 ... Memory section, 15 ... Display device,
17... Latch circuit, 18... Falling edge detection section, 20... Measurement range detection section, 21... Storage section, 22... Multiplexer.

Claims (1)

[Claims] 1 A switch that can be operated from the outside, a determination unit that determines the open/close operation state of the switch, a temperature measurement unit that starts measurement according to the output of the determination unit, and a temperature measurement value obtained by the temperature measurement unit. a first storage section for holding; an in-measurement-range detection section for detecting whether the previous temperature measurement value held in the first storage section is within a predetermined measurement range; and an inside-of-measurement-range detection section. a second storage section that holds the previous temperature measurement value that is within the predetermined range detected by the second storage section; and a display section that switches and displays the current measured temperature value held in the second storage section, and when the switch is closed, the within-measuring-range detection section is activated to display the measured temperature value held in the second storage section. and then opening the switch, the temperature measurement section is activated and the temperature measurement value held in the first storage section is displayed.