JPH0617831B2 - Temperature measuring instrument - Google Patents

Description

Description: [Industrial field of application] The present invention relates to a measuring instrument such as a thermometer, a temperature measuring instrument for observing an instrument, and a temperature measuring instrument for maintenance. In particular, a previous measurement result is confirmed before a measurement operation. The present invention relates to an electronic measuring instrument having a function capable of performing.

[Conventional technology]

This kind of electronic measuring instrument has been adopted in many fields in recent years, and in particular, it is rapidly becoming popular for household use in place of the conventional mercury thermometer because of its simple use.

However, since it does not have a function like the mercury thermometer that can confirm the previous temperature measurement result prior to the temperature measurement operation, it is necessary to make a note of the previous temperature measurement value for each temperature measurement. There was complexity.

In order to solve such a problem, an electronic temperature measuring device has been proposed which has a memory function and holds the temperature measurement result even after the power is turned off so that the temperature measurement result can be read and displayed as needed. : Electronics Digest Co., Ltd., Dec. 10, 1975, "CMOS IC Handbook", pages 287 to 293).

[Problems to be solved by the invention]

In the above conventional technology, a dedicated memory switch for reading the temperature measurement result from the memory unit is provided in addition to the switch for starting the temperature measurement, which complicates the circuit configuration and reduces the entire device. Since the size is increased and the two switches have to be operated separately, the operation is complicated and erroneous, and is not suitable for domestic use mainly by women and girls.

[Means for solving problems]

The present invention has been made in view of the above circumstances, and includes a switch that can be operated from the outside, and a determination unit that determines the open / close operation state of the switch and generates an output signal each time the switch is operated. An operation number detection unit that counts the output signal of the determination unit and detects the number of times the switch has been operated, a measurement unit that starts measurement according to the output of the operation number detection unit, and measurement data of the measurement unit. A storage unit to hold, a measurement range outside detection unit that sets a range to be measured and detects whether or not the measurement data is outside the measurement range, and stores the storage according to the output of the operation number detection unit. And a display unit for displaying the measurement data held in the unit via the out-of-measurement range detection unit, wherein the display unit displays the previous measurement data when the operation number detection unit detects the operation of the switch. Display,
When the next switch operation is detected, the measurement data of this time is displayed.When the measurement data is out of the measurement range, the display mode of the measurement range of the previous measurement data and the measurement range of the measurement data of this time are displayed. The display modes are made different, the circuit configuration is simplified and the entire device is downsized, and the operation is simplified to facilitate handling.

〔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 a 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 measuring unit, 12 is a storage unit, 1
Reference numeral 3 is a measuring range outside detection unit, 14 is a display decoder, 15 is a display device, 16 is a NAND gate, 17 is an RS type latch circuit, 18 is a falling edge detection unit, and 19 to 22 are inverters.

In the figure, the oscillator 2, the counters 3, 5, 7, and 9, the latch circuits 6 and 17, the control unit 10, the temperature measuring unit 11, the display decoder 14, and the falling edge detection unit 18 are supplied to the reset terminal R, respectively. Signal is high level (hereinafter "H")
,) Is in the reset state.

The switch 1 is a normally open switch such as a push button switch that is operated from the outside. When the switch 1 is not operated, one input of the NAND gate 4 is “H”, and the counter 5 and Latch circuit 6
Has been reset since its reset input becomes "H".

The oscillator 2 is a CR oscillator, a crystal oscillator, or the like, and generates a reference clock MCK. This reference clock is divided into a predetermined frequency by the counter 3 and supplied to the counters 5 and 9 and the display decoder 14. Oscillator 2 and counter 3
Means that the output signal of the NAND gate 4 is inverted by the inverter 8 to switch between the operating state and the non-operating state by the MCN signal.

The counter 5 and the latch circuit 6 form a determination unit for determining that the switch 1 has been operated. In this determination unit, the counter 5 prevents malfunction due to chattering of the switch 1. When the switch 1 is operated and is closed for a predetermined period (about 0.1 seconds) or more, it overflows and its Q output becomes low. The level (hereinafter referred to as "L") is inverted to "H". The latch circuit 6 is set at the rising edge of the Q output of the counter 5, and at the same time, its output is inverted from "H" to "L". The counter 5 and the latch circuit 6 are in the reset state when the switch 1 is in the open state, and the reset is released when the switch 1 is in the closed state. Therefore, the latch circuit 6 is operated each time the switch 1 is operated to be in the closed state. The output is inverted from "H" to "L".

The counter 7 is a 2-bit binary counter and counts by 1 at the falling edge of the output of the latch circuit 6. Therefore, the counter 7 detects the number of times the switch 1 is operated. Also, the counter 7 is an output terminal
It has (0), (1) and (2), and in the initial state where the reset is released, the output terminal (0) is "H" and the output terminals (1) and (2) are "L". There is. Then, each time the output of the latch circuit 6 is counted by 1 at the falling edge, the output terminal
(1) and the output terminal (2) become "H" in this order, and when the output of the latch circuit 6 falls, the output terminal (0) becomes "H" and this is repeated thereafter.

Output signal from output terminal (0) of count 7 (hereinafter, GR
ST1) is used as a reset signal for the display decoder 1
4 and also to the NAND gate 4. Therefore, when the GRST1 signal is "H",
The display decoder 14 is reset and the display 15 displays blank (that is, nothing is displayed). When the GRS1 is "L", the display decoder 14 is released from the reset and causes the display 15 to display predetermined data.

The output signal from the output terminal (1) of the counter 7 is inverted by the inverter 20, and is output as the EN signal outside the measurement range detection unit 13
Is supplied to the EN terminal. Out-of-measurement range detector 13 is EN
When the signal is "H", it is set to the inactive state, and when the EN signal is "L", it is set to the operating state.

The output signal from the output terminal (2) of the counter 7 is inverted by the inverter 19 and supplied as the GRST2 signal to the count 9, the control unit 10, the temperature measuring unit 11, the latch circuit 17, the falling edge detection unit 18, and the inverter 21. It

The counter 9 further divides the clock from the counter 3, and the _Ql output having a predetermined division ratio is supplied to the control unit 10 to control the temperature measurement timing in the temperature measurement unit 11. When the counter 9 overflows, its Qm output is inverted, but the latch circuit 17 is set at the first rising edge of this Qm output, and its output is inverted from "H" to "L". This output is the falling edge detector 1
8 to form the MAX R signal which represents its falling edge. This MAX R signal resets the storage unit 12 which is a D-type flip-flop, and the previous temperature measurement data held so far is erased.

The temperature measuring unit 11 periodically measures the temperature, but the first temperature measurement is completed immediately before the second rising edge of the Q _l output of the counter 9, and the temperature measurement at this time is synchronized with this rising edge. The value is compared with the temperature measuring unit held in the storage unit 12. Hereinafter, Q _l measurement of temperature for each rising edge just before the output of the counter 9 is completed once, this every time, temperature measuring value at that time (hereinafter, referred to as current measurement Yutakachi) is held between the storage section 12 The measured temperature value is compared, and when the current measured value is large, the temperature measuring unit 11 generates a MAXφ signal, and the storage unit 12
In place of the temperature measurement value held so far, the current temperature measurement value is written. Therefore, the storage unit 12 retains the maximum temperature measurement value obtained so far.

The temperature measurement value stored in the storage unit 12 is read out, supplied to the display decoder 14 via the out-of-measurement range detection unit 13, and displayed on the display unit 15. The temperature measurement value read out from the storage unit 12 is read. When the value is out of the predetermined measurement range, the display unit 1
In order to display that fact, the out-of-measurement range detection unit 13 outputs to the display decoder 14 data representing fixed numerical values, symbols, patterns, etc., instead of the temperature measurement value.

Here, the predetermined measurement range is 32.0 ° C to 42.0 ° C. When displaying the temperature measurement value of the previous temperature measurement stored in the storage unit 12 before being reset by the MAX R signal, the out-of-measurement range detection unit 13 displays "32.0 ° C" when it is less than 32.0 ° C. When it exceeds 42.0 ° C, “42.0 ° C” is displayed. Further, when displaying the present temperature measurement value stored in the storage unit 12 after being reset by the MAX R signal, when this is less than 32.0 ° C.,
When the temperature exceeds "LO ° C" or 42.0 ° C, a symbol or pattern such as "HI ° C" is displayed. Thus, in order to display the previous temperature measurement value and the current temperature measurement value outside the predetermined measurement range differently, the measurement range outside detection unit 13 is controlled by the EN signal. That is, the EN signal is "L" in the display period of the previous temperature measurement value and "H" in the display period of the current temperature measurement value.

The display decoder 14 decodes the data from the out-of-measurement range detection unit 13 after the reset is released due to the GRST1 signal becoming “L”, and causes the display unit 15 to perform the above display. The signal is preset by the "H" DisPR signal supplied from 22 to the preset terminal PR, and the display unit 15 is supplied with a signal for lighting all the segments.

Next, the operation of this embodiment will be described with reference to FIG. 2 showing the operation timing of each part.

The previous temperature measurement value is held in the storage unit 12 even in the non-use state. When a power source (not shown) is turned on, the display unit 1
5 is in the operating state. At the same time, the reset of the counter 7 is released, but the GRST from its output terminal (0)
Since one signal is at "H", the display decoder 14 is in the reset state and the display 15 is displaying a blank. Also, the switch 1 is open and both inputs of the NAND gate 4 are "H", so that the output of the NAND gate 4 is "L" and the oscillator 2 and the counter 3 are in the reset state. Further, the counter 5 and the latch circuit 6 are also in the reset state, and the output signal of the output terminal (2) of the counter 7 is “L” and the GRST2 signal is “H”. The temperature section 11, the latch circuit 17, and the falling edge detection section 18 are in a reset state.

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

The counter 5 counts the clock output from the counter 3, but when the switch 1 is closed for about 0.1 seconds or more, the counter 5 overflows and its Q output is inverted from "L" to "H". This inversion sets the latch circuit 6, and its output is inverted from "H" to "L". The counter 7 is set to 1 at the falling edge of this output.
The GRST1 signal from its output terminal (0) changes from "H" to "L", the output signal from its output terminal (1) changes from "L" to "H", and the EN signal changes to "H". "L" is inverted.

As a result, the display decoder 14 is released from reset.
The previous temperature measurement value N _x ′ is read out from the storage unit 12, and this previous temperature measurement value N _x ′ is supplied to the display decoder 14 via the out-of-measurement range detection unit 13, where it is decoded and displayed on the display unit 15.
Is displayed as "T _X '° C". In this case, the previously measured temperature value N _x ′ is displayed as a fixed value of “32.0 ° C.” or “42.0 ° C.” as described above when it is outside the predetermined measurement range.

When the switch 1 is opened, the counter 5 and the latch circuit 6 are reset again or the GRST1 signal is "L", so that the output of the NAND gate 4 is held at "H",
Therefore, the MCKN signal is also at "L" and the oscillator 2
And the counter 3 is operating.

As long as the switch 1 is not closed again, this state is maintained and the previous temperature measurement value N _x ′ is continuously displayed on the display unit 15.

Next, when the switch 1 is closed, the reset of the counter 5 and the latch circuit 6 is released again. Further, since both inputs of the NAND gate 4 are "L", MCKN
The signal remains "L" as it is, and the oscillator 2 continues.
And the counter 3 is operating.

Therefore, when the switch 1 is closed for about 0.1 seconds or more, the counter 5 overflows and the output of the latch circuit 6 is inverted from "H" to "L". As a result, the counter 7 counts one and the output signal of the output terminal (1) is "H".
To "L", the EN signal is inverted from "L" to "H", and the output signal from the output terminal (2) is inverted from "L" to "H" and the GRST2 signal is "H". "L" is inverted.

Then, the reset of the counter 9, the control unit 10, the temperature measurement unit 11, the latch circuit 17, and the falling edge detection unit 18 is released, and the counter 9 starts counting the clock from the counter 3. At the same time, the “L” GRST2 signal is inverted by the inverter 21 and supplied to the NAND gate 16, and the “H” output of the latch circuit 17 is supplied to the NAND gate 16.
The output of 6 is "L" and therefore the inverter 22
The DisPR signal, which is the output of, is inverted from "L" to "H". As a result, the display decoder 14 is preset with this DisPR signal, the acceptance of data from the out-of-measurement range detector 13 is prohibited, and all the segments of the display 15 are turned on.

As described above, by lighting all the segments of the display device 15, it is possible to confirm that the display decoder 14 and the display device 15 are normally operated prior to the start of temperature measurement.

During the lighting period of all the segments, the operation of the switch 1 is completed and opened, and the counter 5 and the latch circuit 6 are reset. Further, the input from the switch 1 side of the NAND gate 4 is inverted from “L” to “H”, but the GRST1 signal remains “L”, the MCKN signal is also “L”, the oscillator 2, the counter 3 Is still active.

The counter 9 keeps counting, and at a predetermined count value, Q _l
Although the output is inverted from "L" to "H", the control unit 10 detects this, but does not output a signal to the temperature measuring unit 11. Then, Qm output counter 9 is finally overflows is inverted to "H" from "L", Q _l the output is inverted to "L" to "H". With this inversion of the Qm output, the latch circuit 17 is set and its output is inverted from "H" to "L". The falling edge of this output is detected by the falling edge detection unit 18 to form a MAX R signal, whereby the storage unit 12 is reset. As a result, the previous temperature measurement value N _x ′ is erased and the value 0 is held in the storage unit 12.

Further, since the output of the latch circuit 17 becomes "L", the output of the NAND gate 16 becomes "H", and therefore the DisPR signal becomes "L".
Resets the preset. As a result, the display decoder 1
4, the temperature measurement value read from the storage unit 12 is supplied via the out-of-measurement range detection unit 13. In this case, this temperature-measurement value is 0 and is outside the measurement range, that is, 32.0. Since the temperature is lower than ° C, the out-of-measurement range detection unit 13 supplies the data representing "LO ° C" to the display decoder 14, and therefore the display 15 displays this.

The counter 9 restarts counting after overflow, but when the count value reaches a predetermined value and the _Ql output is inverted from "L" to "H", the control unit 10 detects this inversion and outputs a signal. Send to the temperature measuring unit 11.

On the other hand, the temperature measurement unit 11 has completed the first temperature measurement immediately before the _Ql output of the counter 9 rises, and when a signal from the control unit 10 is received, the temperature measurement value is read from the storage unit 12. Compare with the current measured value N ₁ . In this case, since the read temperature measurement value is 0, the current temperature measurement value N ₁ is larger. Therefore, the temperature measurement unit 11 sends the MAXφ signal to the storage unit 12 to output the current temperature measurement value N ₁ . Write in the storage unit 12. As a result, the display value "T ₁ ° C" for the measured temperature value N ₁ is displayed on the display unit 15.

In addition, after the counter 9 starts counting from the beginning, Q _l
Here, the period until the output rises to a predetermined count value is set to about 0.7 seconds, and the period until the counter 9 overflows and the Q _m output is inverted is the second.
It is set to about 1.4 seconds, which is double.

Therefore, the period in which "LO ° C" is displayed is about 0.7 seconds.

Further, the counter 9 overflows continues to count, Q _m output is inverted from "L" to "H", the counter 9 is inverted from "L" to Q _l also "H" begins to count again from the beginning . Then, after about 0.7 seconds, the _Ql output is inverted from "L" to "H", and accordingly, in the temperature measuring unit 11, the current temperature measured value N ₂ obtained immediately before that and the storage unit 1 are stored.
The temperature measurement value N ₁ held in 2 is compared, and when the current temperature measurement value N ₂ is larger, the storage unit 12 rewrites the current temperature measurement value N ₂ . Therefore, in the display unit 15,
The display value "T ₂ ° C" for this temperature measurement value N ₂ is displayed.

In this way, as long as the switch 1 is not operated, for each count repetition of the counter 9, the current temperature measurement value at the rise time of the Q _l output and the temperature measurement value held in the storage unit 12 are compared, measured current When the temperature value is larger, the storage unit 12 rewrites the current temperature value. Therefore, the display 15 displays the maximum temperature measured so far, and the displayed value is updated as the temperature rises.

In this case, every time the counter 9 overflows, Q _m
Although the output is inverted, the latch circuit 17 is held in the set state.

Next, when the switch 1 is closed, the reset of the counter 3 and the latch circuit 6 is released. Also in this case MCK N
Since the signal is held at "L", the oscillator 2 and the counter 3
Is in working condition. 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 is inverted from "H" to "L". This makes counter 7
Counts one, and as a result, GR from the output terminal (0)
The ST1 signal is inverted from "L" to "H", the display decoder 14 is reset, and the display 15 displays blank.

At the same time, the output signal of the output terminal (2) of the counter 7 is inverted from "H" to "L", and the GRST2 signal is inverted from "L" to "H". As a result, the counter 9,
The control unit 10, the temperature measurement unit 11, the latch circuit 17, and the falling edge detection unit 18 are also reset. In this case, MAX
Since the R signal is not generated, the maximum temperature measurement value N _x so far is held in the storage unit as it is. This temperature value N
_x is the previous temperature measurement _value for the next temperature measurement.

Then, when the switch 1 completes the operation and opens, the counter 5 and the latch circuit 6 are reset. With this,
Since both inputs of the NAND gate 4 become "H", M
The CK N signal also becomes "H", and the oscillator 2 and the counter 3
Is also reset and becomes inactive, the temperature measurement operation is completed, and the system stops.

As described above, in this embodiment, every time the single switch 1 is operated, the previous temperature measurement value and the maximum temperature measurement value are switched and displayed. Since the previous temperature measurement value is displayed as it is, unless the switch 1 is operated after the start of display, it is necessary to store the previous temperature measurement value for comparison with the current temperature measurement value, for example. I have enough time.

Also, when the measured temperature value is outside the measurement range, different values, symbols, and patterns are displayed between the previous measured temperature value and the current measured temperature value. And can be clearly distinguished.

Further, before the temperature measurement is started, the storage unit 12 is reset and the stored contents become 0. As a result, the display unit 15 displays “LO”.
"° C" is displayed, which confirms that the temperature measurement has started.

Furthermore, before starting the temperature measurement, all the segments of the display unit 15 are turned on to display the display decoder 14 and the display unit 15.
Can be confirmed to be operating normally.

Although specific numerical values are shown in the description of the above-mentioned embodiments, these are merely examples and the present invention is not limited to these values.

If the switch 1 can be opened and closed from the outside,
Various types such as a push button type, a slide type, a reed switch provided in a main body case (not shown) and operated by a magnet from the outside can be used.

〔The invention's effect〕

As described above, according to the present invention, the switching display between the previous temperature measurement value and the current temperature measurement value and the start and stop of the temperature measurement operation can be performed by operating a single switch. , The display time of the previous temperature measurement value can be arbitrarily set by not operating the switch, the operation is extremely simplified and the handling becomes extremely easy,
Further, the structure is simple and the size can be reduced.

When the measurement data is out of the measurement range, the display mode outside the measurement range of the previous measurement data and the display mode outside the measurement range of the current measurement data are made different (since the measurement data is out of the measurement range, There is no problem even if the display mode is changed with symbols or patterns), and it is possible to obtain an excellent effect that it is possible to visually distinguish whether the currently displayed data is the previous measurement data or the current measurement data. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a temperature measuring device according to the present invention, and FIG. 2 is a timing chart for explaining the operation of FIG. 1 ... Switch, 5 ... Counter, 6 ... Latch circuit,
7, 9 ... Counter, 10 ... Control unit, 11 ... Temperature measuring unit, 12 ... Storage unit, 15 ... Display unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Isao Imagawa 4680 Ikata, Hachijo-machi, Tagawa-gun, Fukuoka Prefecture Within Hitachi Maxell, Kyushu (56) Reference JP-A-57-60229 (JP, A) Sho 59-100233 (JP, U)

Claims (1)

[Claims] 1. A switch that can be operated from the outside, a determination unit that determines the opening / closing operation state of the switch, generates an output signal each time the switch is operated, and counts the output signal of the determination unit, An operation number detection unit that detects the number of times the switch has been operated, a measurement unit that starts measurement according to the output of the operation number detection unit, a storage unit that holds the measurement data of the measurement unit, and a range to be measured. A measurement range outside detection unit that is set to detect whether the measurement data is outside the measurement range, and the measurement data held in the storage unit according to the output of the operation count detection unit A display unit for displaying via an outer detection unit, wherein the display unit displays the previous measurement data when the operation of the switch is detected by the operation number detection unit,
When the next switch operation is detected, the measurement data of this time is displayed.When the measurement data is out of the measurement range, the display mode of the measurement range of the previous measurement data and the measurement range of the measurement data of this time are displayed. Measuring instrument characterized by different display modes.