JPS5818797A - Informer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention: This invention generates an alarm using the detection signal of a sensor that generates a detection signal like a gas sensor (heater heating type) and also generates a pseudo detection signal during the initial stabilization period at the beginning of energization. The present invention relates to a notification device such as a gas leak alarm device that can prevent false alarms caused by detection signals.

A conventional gas leak alarm device of this type has an output V of the gas sensor 1, as shown in Fig. JllE1 (Fig. J!I2 (A)).
The output of the level detection circuit 2 when the voltage exceeds the alarm level v1. changes from L level to H level, and this H level output activates alarm circuit 4 via AND gate 3.
A trap is configured to activate the external output circuit 5 in response to the activation of the alarm circuit 4. However, the gas sensor 1
When gas is detected, the output increases and exceeds the alarm level V, and also during the initial stability period T1 at the beginning of one energization, the output increases and exceeds the alarm level V1, and if left as is, a false alarm will occur during the initial stability period T□. will occur.

In order to prevent this false alarm, the timer time T2 is longer than the 1!71st period stability period T, and the timer time T2 is set after the start of energization.
The opening/closing pipe of the AND gate 3 is controlled by a timer circuit 6 in which the output V (Fig. 2 (C)) is at L level until the period elapses, and the output V changes to H level after that period. During the initial stable period T An alarm is issued by the H level output (shown in FIG. 2) of the level detection circuit 2.

When using the timer mentioned above, the initial stabilization period T of the gas sensor is in the range of about 1 to 6 minutes, and in order to prevent false alarms from occurring for any gas sensor IK, it is necessary to set it to the maximum of 6 minutes or more. must be set.

In this way, the length K of the initial stable period T of the gas sensor 1 is
Regardless, since the timer time T2 is set to be longer than the maximum time, even if the gas sensor 1 is in a stable state, it will be considered to be in an inactive state in response to the detection signal until the fixed timer time T has elapsed. Because there is.

There has been a problem in that it takes more time than necessary when performing an operation test, so the purpose of the present invention is to reliably prevent false alarms caused by false detection signals, and 4. to improve the inactivity period for detection signals. An object of the present invention is to provide a notification device that can shorten the length of time.

An embodiment of this invention is shown in FIG. Namely.

This gas leak alarm includes a level detection circuit 14 that generates a detection output in response to a sensor output exceeding the alarm level, and a timer that starts measuring time in response to power-on. and a timer circuit 15 that switches between long and short in response to the presence or absence of one.

The detection output of the level detection circuit 14 and the timer circuit 1
Theory of logical product with time-up output of 5, embedded circuit 1
6, and a notification circuit 1 that responds to the output of the AND circuit 16.
7, the short timer time of the timer circuit 15 is made shorter than the sensor initial stability period, and the long timer time is made longer than the sensor initial stability period. In this case, the notification circuit 7 is the level detection circuit. The output of the AND circuit 16 is supplied to the collector of the #II transistor Tr via the light-emitting side element of the photocoupler PC, and the output of the flicker circuit F is temporarily operated based on the detection output of the switch 14. The first transistor T r
a second transistor T r 2 supplied to the base of x and inverting the collector output of this first transistor T r 2;
As a result, the buzzer BZ is operated intermittently, the light-emitting side element of the photocoupler PC is operated continuously, and the external output circuit 18 is continuously operated by the light-receiving side element of the photocoupler PC.

To explain it more forgivingly, this gas leak alarm is.

From time to to time t0 immediately after energization, gas discharge (
5) The output of the sensor is lower than the alarm level, and the output of the level detection comparator CP1 is KL as shown in Fig. 5(A)K.
V F/I/T A, timer comparator L/-
The voltage vP at the positive input terminal of cP2 is vP=vP=vF+vcfPL as shown in Figure 5. However, (2) is the forward voltage drop of the diode drawer, and is the L level output voltage of the vOPL comparator cP1.

On the other hand, the voltage ■ at the negative input terminal of comparator CP2.

, is the capacitor C charged through the resistors R□, R2
However, from time to to time t1, the voltage vP (=
Therefore, the output of comparator CP2 is at the KL level as shown in FIG. 5(2).

Also, since the output of the comparator CP is at L level, the voltage at the minus input terminal of the flicker comparator CP3 is lower than the voltage at the plus input terminal given by the resistors R8, R, so the output of the comparator (6) CF2 is At H level, the visible light emitting diode IJD lights up as shown in FIG. 115 (6) to indicate energization. On the other hand, the outputs of comparators CP□ and CP2 are both at the L level, transistors Try + Tr2 are both off, the buzzer BZ does not sound, the photocoupler PC does not operate, and the external output circuit 18 does not operate. , After that, when the output of the gas sensor exceeds the alarm level due to false detection, the output of the comparator CP will not go to the H level, and the voltage at the positive input terminal of the comparator CP2 will decrease.
A increases to 4 vP=vP2=vCOXRyo+R3+R4.

However, R, >> R, R3, R, and resistance R3
is ignored.

On the other hand, the voltage at the negative input terminal of comparator CP2 is 0
1ij Although it increases as time passes, the voltage vP (=
■Since it is lower than a), the output of comparator CP2 is L.
Hold the level. At time t, during the initial stabilization period of the gas sensor, the voltage ■. , exceeds the voltage vP.

Since vP=vP2, comparator CP2 does not change.

Since the output of 11 comparator CP is at H level,
The comparator CP3 flickers (L level output and H level output occur alternately) by the resistors R8 to R1□ and the capacitor C2, and the visible light emitting diode LED
On the other hand, blink to indicate that the gas sensor is generating a false detection signal.

The output of the comparator CP is at the H level, but since the output of the comparator CP is at the L level, both the transistors Tr and Tr2 are off and the buzzer BZ is off.
and hot turnip? PC doesn't work.

When the gas sensor becomes stable and its output becomes lower than the alarm level at time t3, the output of the comparator CP becomes L level, and vP=vP. At this time, vo,
〉■1□, so the output of comparator CP2 immediately becomes H level, -vP='P2, and resistors R,, R? Charging current flows from the midpoint of , through diode D, and into capacitor C.

The capacitor C0 is rapidly charged and the voltage v0 quickly exceeds the voltage vP2 to reach the maximum charging voltage V. 1m (= ■O0
×R″) reaches 0.However, R2>>R5,R,
5+RヮruO At this time, when the output of the comparator CP is at the L level, the visible light emitting diode LED lights up. On the other hand, since the output of the comparator CP2 is at L level, the output of the comparator CP2 is at L level, so the transistors Trl I Tr2 are both off, and the buzzer BZ and photocoupler PC do not operate. Until t5, when the gas sensor detects gas and the output exceeds the alarm level, the output of comparator CP1 becomes H level, and comparator CP3
flickers and the visible light emitting diode LED flashes to indicate gas detection. In addition, since the output of the comparator CP2 is also at H level, the collector voltage is supplied to the transistor Tr via the light emitting diode of the photocoupler PC, and the base voltage is supplied to the transistor Tr2. In response to the flicker operation of the comparator CP3, the transistor Tr2 is turned on and off, and the buzzer BZ is turned on and off in response to the flicker operation of the comparator CP3, causing the buzzer BZ to beep intermittently in the opposite way to the blinking of the visible light emitting diode LED, as shown in Fig. 115, to average the current consumption. The collector current of the transistor Tr2 and the pace current of the transistor Tr2 alternately flow through the light-emitting diode of the photocoupler PC, which has become a photocoupler. Turns on and external output circuit ・18f: Operates continuously.

After time t5, when the gas runs out, the output of the comparator CP becomes L level, the visible light emitting diode LED lights up continuously, and the buzzer BZ and photocoupler PC stop operating. When the gas sensor becomes stable before , exceeds the voltage vP1, the visible light emitting diode LED turns on at that point, and when gas is turned on at this time, the visible light emitting diode LED blinks, but the buzzer BZ
And Hotokabu 9PC does not work (10).

If the gas sensor is in the gas above the alarm level at the time of initial energization, the comparator CP□ maintains the H level until the gas becomes below the alarm level after time tU, and waits at the voltage vPFivP0. Voltage V. , Ke1
IIi5 (as shown by the broken line of
C operates and voltage V. □ is the voltage voIM4! 0 but 1. v(l?LM satisfies the following equation.

By selecting an appropriate ratio of these voltages V and R: (R3+R,), a capacitor C with low withstand voltage can be selected. Therefore, a relatively low value for resistor R2 can be selected. , is strong against leakage current of the capacitor C□, has a stable timer time, and can reduce the cost of the capacitor C.

a diode that compensates for the forward voltage drop of diode D;
D4 is a diode for discharging the capacitor C when the power is turned off.

As a result of this configuration, it is possible to reliably prevent false alarms due to false detection signals, and to shorten the period of inactivity in response to detection signals.

In addition, another conventional gas leak alarm device uses AND gate 3 to give a sense of urgency due to the alarm, as shown in Figure 3.
The alarm flicker circuit 7 is activated by the output of the alarm flicker circuit 7, and the transistor 8 is turned on and off by the output of the alarm flicker circuit 7 to cause the buzzer 9 to sound intermittently. However,
Since a continuous signal is required as the signal sent to the external output circuit 5, the voltage across the buzzer 9 is smoothed by the resistor lO and the capacitor 11, and this smoothed voltage is applied to the transistor 13 via the resistor 12. is continuously turned on 111.

However, such a configuration requires circuits (10 to 13) for converting flicker signals into continuous signals, resulting in an increase in the number of parts and a problem of high cost.

Furthermore, the DC signal to be applied to the external output circuit 5 can be taken from the AND gate 3, but in this case.

It is necessary to separate the signal supplied to the alarm flicker circuit 7 by a logic circuit or the like, which poses a problem of increasing the number of parts and increasing costs.

However, in the above embodiment, the flicker signal that causes the buzzer Bzt to operate intermittently and the DC signal that causes the external output circuit 18 to operate continuously can be separated using only the photocoupler PC, and the number of parts is small and the cost is low.

As described above, the notification device of the present invention includes a level detection circuit that generates a detection output in response to a sensor output that is equal to or higher than the notification level, and a timer that starts measuring when the power is turned on. a timer circuit that switches between long and short in response to presence or absence; an AND circuit that ANDs the detection output of the novel detection circuit and the time-up output of the timer circuit; and a notification circuit that responds to the output of the AND circuit.

and a sensor (13) for detecting the short timer time of the timer circuit.
) Since the long timer time is shorter than the initial stabilization period of the senna and longer than the initial stabilization period of the senna, it is possible to reliably prevent false alarms due to false intelligence signals and shorten the period of inactivity in response to the detection signal. ,?

[Brief explanation of drawings]

Figure 1 is a block diagram of a conventional gas leak alarm, Figure 2-(2) is a signal waveform diagram of each part, Figure #I3 is a block diagram of another conventional gas leak alarm, and Figure 4 is a block diagram of a conventional gas leak alarm. A circuit diagram of a gas leak alarm according to an embodiment of the present invention, FIG. 5 (4) to (■) are waveform diagrams of each part thereof.
] 5... Timer circuit, 16... AND circuit, 17.
...Notification circuit, 18...External output circuit, F...Flicker circuit, Tr work, Tr2...Transistor, PC...
...Hotocoupler (14)

Claims (2)

[Claims] (1) A level detection circuit that generates a detection output in response to the notification level of the senna output or higher, and a timer that switches the timer time, which starts counting when the power is turned on, to a longer or shorter time in response to the presence or absence of the output of the level detection circuit. a circuit, an AND circuit for ANDing the detection output of the level detection circuit and the time-up output of the timer circuit, and a notification circuit responsive to the output of the AND circuit; and a long timer time that is shorter than the sensor initial stability period and longer than the sensor initial stability period. (2) The notification circuit causes a flicker circuit to respond to the detection output of the level detection circuit, supplies the output of the AND circuit to the collector of the transistor jIll via the light emitting element of the photocoupler, and also controls the flicker circuit. A second transistor that supplies an output to the base of the first transistor and inverts the collector output of the first transistor operates the alarm intermittently and continuously operates the light emitting side element of the photocoupler. The notification device according to claim 1, wherein the external output circuit is continuously operated by the light receiving side element.