JPH0431674Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a malfunction prevention device for a fire alarm system.

[Background technology]

The circuit shown in FIG. 3 is a conventional circuit which is the basis of the present invention, and this circuit is constructed as follows. The constant voltage circuit section 3 converts the DC output between the existing positive power output terminal _I0 and the common line connection terminal C, which are provided for supplying DC power from the receiver A to the sub-receiver etc., to a DC voltage of a predetermined voltage. It stabilizes the power and supplies it as a power source to each circuit described below. The switching circuit 5 turns on when the detection output from the line voltage detection circuit section 4, which is a line state detection means, is input.
This is for driving the high sensitivity relay 6. The high-sensitivity relay 6 is a high-sensitivity type that operates faster than the time it takes for the receiving relay Ry ₁ ... of the receiver A to operate, and the receiving relay Ry ₁ ... is energized. It became possible to reverse the relay contact _r0 from normally closed contact b to normally open contact a before forming the self-holding circuit with relay contact r ₁₁ ... of receiving relay Ry ₁ .... There is. That is, the high sensitivity relay 6 is a receiving relay.
It functions as a switching means with a shorter operation time than Ry ₁ . Relay contact r ₀ is inserted in series at the starting end of the common line l _c that connects the normally closed contact b side to the common line connection terminal C, and when the normally closed contact b is opened, the common line l _c and the common line The connection terminal C is cut off, and the power supply from the receiver A to the smoke detector 1a etc. connected between the common line _Lc and the sensor connection lines _L1 to _L0 is stopped. It is designed to cut off the excitation circuit of the receiving relay Ry ₁ in A. When the line voltage detection circuit section 4 generates the first detection output and the switching circuit section 5 starts to turn on, the first timer circuit section 7 starts a time-limited operation from this start, and when a predetermined period of time has elapsed, it outputs a time-up output. is output to the second timer circuit section 8, and the time limit operation time of the first timer circuit section 7 is set to 10 to 20 seconds. The second timer circuit section 8 starts a time-limited operation when the first timer circuit section 7 times up, and during this operation period, the operation of the switching circuit section 5 is forcibly set to an OFF state. The line voltage detection circuit section 4 switches the voltage detection input terminal for each line.
It is connected to each sensor connection line l ₁ to _{l o} via SW ₁ to SW _o and diodes D ₁ to _{D o} , and each diode
D ₁ to D _o constitute a diode OR. Thus, a malfunction prevention circuit 9 attached to the existing receiver A is configured from the line voltage detection circuit section 4, the switching circuit section 5, the first and second timer circuit sections 7 and 8, and the high sensitivity relay 6. do. L ₁ to _Lo are sensor connection line connection terminals that connect the respective sensor connection lines l ₁ to _lo . Next, the operation of the conventional circuit will be explained.

Now, assuming that each switch SW ₁ to _{SW o} is turned on and each line is in a normal state, the line voltage between each sensor connection line l ₁ to _{l o} and the common line l _c is approximately the same as above. Since the voltage is equal to the voltage of the DC power supply, the detection output of the line voltage detection circuit section 4 is "L" level, and the switching circuit section 5 does not operate. Next, for example, when the smoke detector 1a connected to the sensor connection line _l1 detects smoke and turns on, a short circuit is created through the impedance within the smoke detector 1a, and the wires _l1 and _lc are short-circuited. The voltage drops and is immediately discriminated by the line voltage detection circuit section 4, which generates an "H" level detection output and turns on the switching circuit section 5. This ON operation drives the high-sensitivity relay 6, and the normally closed contact b of the relay contact _r0 of the high-sensitivity relay 6 is turned off, opening the common line _LC . By this opening, a receiving relay Ry ₁ is formed by the receiving relay Ry 1 corresponding to the sensor connecting line l ₁ in the receiver A, the sensor connecting line l ₁ , the smoke detector 1a, and the common line _{lc .}
The energizing path for the excitation current will be cut off.
That is, if the high-sensitivity relay 6 operates earlier (for example, 1 msec) than the time required for the operation of the receiving relay Ry ₁ (for example, 10 msec), the receiving relay Ry ₁ does not operate and the receiver A does not issue an alarm. Now, simultaneously with the ON operation of the switching circuit section 5, the first timer circuit section 7 starts a time-limiting operation. Here, during the time limit operation period of the first timer circuit section 7, that is, during the ON operation of the switching circuit section 5, the starting end portion of the common line _LC is open due to the normally closed contact b of the relay contact _r0 being turned off. The smoke detector 1a, which had been operating due to the power supply from the receiver A, becomes inoperable and returns to normal operation, and since the line voltage is restored, a detection output is generated from the line voltage detection circuit section 4. The switching circuit section 5 is turned off. As a result of this turning off, the high sensitivity relay 6 returns to its original state and turns on the normally closed contact b of its relay contact _r0 . As a result of this turning on, the DC voltage from receiver A is again applied between both lines l ₁ and l _c . Power is also supplied to the smoke detector 1a, but whether the smoke detector 1a is a photoelectric type or an ion type, it takes several seconds to 10 seconds from the time the power is turned on until the smoke detector starts operating. Since it takes about a second, the smoke detector 1
a turns on again. This ON operation causes the line voltage to drop and the line voltage detection circuit section 4 again generates a detection output, turning on the switching circuit section 5 and driving the high sensitivity relay 6. In this way, the high-sensitivity relay 6 is driven every time the smoke detector 1a operates, thereby preventing the receiving relay Ry ₁ of the receiver A from operating and self-holding. The operable time of this high-sensitivity relay 6 is defined by the time limit operation time (for example, 10 seconds) of the first timer circuit section 7. In other words, when the first timer circuit section 7 times up, a time-up output is sent to the second timer circuit section 8, and the second timer circuit section 8 is operated for a limited time from the time-up of the first timer circuit section 7, and the time-limited operation is performed. During this period, a signal is generated to turn off the switching circuit section 5. Therefore, when the smoke detector 1a operates during the time limit operation period of the second timer circuit section 8, the receiving relay Ry ₁ of the receiver A is connected to the sensor connecting line _l1 and the smoke detector 1 is connected to the receiving relay Ry 1 of the receiver A.
a, common line 1c, and normally closed contact b of relay contact r ₀
An excitation current flows through the receiver relay Ry 1 and the receiver relay Ry ₁ operates, forming a self-holding circuit and causing the receiver A to issue an alarm. By the way, the time limit operation period of the second timer circuit section 8 (for example,
40 seconds), if the smoke detector 1a does not operate, the receiving relay Ry ₁ of the receiver A will not operate, and this means that the sensor will not operate during the time limit operation period of the first timer circuit section 7. This indicates that the error was a temporary malfunction, and false alarms due to malfunction could be prevented. If there is a sensor operation after the end of the time limit operation of the second timer circuit section 8, the line voltage detection circuit section 4, the switching circuit section 5,
By working with the high-sensitivity relay 6, the line opening operation is performed in the same manner as described above.

That is, the line voltage detection circuit section 4 is connected to the smoke detector 1.
When the switch a operates, the detection output is set to the "H" level as shown in FIG. Therefore, when the detection output rises to the "H" level, the high sensitivity relay 6 turns on as shown in FIG. 4b (the period of the upper level in the figure is the on period). Further, at the same time that the switching circuit section 5 is turned on, the first timer circuit section 7 starts a time-limited operation as shown in FIG. When the circuit section 7 times out, the second timer circuit section 8 starts a time-limiting operation as shown in FIG. 4d (the period at the upper level in the figure is the time-limiting operation period).

By the way, if the time from the first detection output generated by the operation of the smoke detector 1a to the alarm is issued is, for example, 15 seconds, the remaining time of the time-limited operation of the second timer circuit 8 is
It is possible to accept the operation of the sensor on the other line for 35 seconds, so the sensor on the other line works and the output of the line voltage detection circuit 4 goes to the "H" level as shown in Figure 4e. When the line rises (the upper level in the diagram is "H" level), the receiving relay corresponding to this line is immediately activated to issue an alarm. In other words, the storage function did not work for this line, and it had the disadvantage of accepting temporary malfunctions.

[Purpose of invention]

This invention was created in view of the above-mentioned problems, and its purpose is to restore the storage function to another line at the same time that an alarm is issued for a certain line. The purpose of the present invention is to provide a malfunction prevention device for a fire alarm system.

[Disclosure of invention]

The present invention will be explained below with reference to examples.

FIG. 1 shows a circuit of an embodiment, and circuits in the same figure with the same symbols and numbers as those in the circuit in FIG. 3 have the same configuration and function. The difference from the circuit in Figure 3 is that an NPN type transistor Tr is inserted in the positive line of the DC power supply path connected to the input side of the constant voltage circuit section 3, and in normal times, it is inserted between the collector and the base. The connected resistor R ₁ applies a base bias to the transistor Tr ₁ to turn it on, and DC power is supplied to the constant voltage circuit section 3 . Furthermore, between the base of this transistor Tr ₁ and the negative line, a series circuit is connected between the normally open contact of the changeover switch r ₂₁ , which is the relay contact of the receiving relay Ry ₁ , and the capacitor C ₁ . Multiple receiving relays are inserted corresponding to Ry ₁ ... A discharge resistor R ₂ is connected in parallel to each capacitor C ₁ through a normally closed contact of a changeover switch r ₂₁ .

In this embodiment circuit, a fire detector connected to a certain line is activated, and the detection output of the line voltage detection circuit section 4 initially becomes "H" as shown in FIG. 2a.
When the level rises (the upper level in the diagram is “H”)
level), the first timer circuit section 7 starts a time-limited operation as shown in FIG. The timer circuit section 8 starts the time-limiting operation as shown in FIG. 2d (the period at the upper level in the figure is the period of the time-limiting operation). During the time limit operation of the second timer circuit section 8, the smoke detector 1a operates and the detection output of the line voltage detection circuit section 4 becomes "H".
When the level is reached, the corresponding receiving relay, for example Ry ₁ , operates in the same way as the circuit in Figure 3, and its relay contacts
At the same time as r ₁₁ is closed, changeover switch r ₂₁ is reversed. This inversion connects the capacitor C ₁ between the base of the transistor Tr ₁ and the negative line, and the transistor Tr ₁ is turned off for an instant until the charging voltage of the capacitor C ₁ reaches a predetermined level. Therefore, the power supply to the malfunction prevention circuit 9 is stopped and the second timer circuit section 8 is reset as shown in FIG. 2d. After that, when the fire detector on another line operates and the detection output rises to the "H" level as shown in Figure 2 e (the upper level in the diagram is the "H" level), first the first timer circuit section 7
starts operating, and the circuit is interrupted by the high-speed relay 6 as shown in FIG. 2b for the detection output during that operating period. When the time-limited operation of the first timer circuit section 7 ends and the second timer circuit section 8 starts operating, the corresponding reception relay is enabled to operate during that operation period. In this way, each time an alarm is issued for each line one after _another , the second timer circuit section 8 is reset by the changeover switch _r21 of the reception relay Ry1 of the line and the capacitor _C1 ... , the storage function can be restored.

[Effect of idea]

Since the present invention is configured as described above, when an alarm occurs on a certain line, the time limit operation of the second timer circuit section of the malfunction prevention circuit can be immediately reset, so that the original second timer circuit can be reset. Even if the operation of a fire detector on another line is detected during the time limit operation period of the first timer circuit, the storage function can be activated by the operation of the first timer circuit, further improving reliability. play.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of an embodiment of the present invention, Fig. 2 is an explanatory diagram of the same operation as above, Fig. 3 is a circuit diagram of a conventional example, and Fig. 4 is a circuit diagram of an embodiment of the present invention.
The figure is an explanatory diagram of the same operation as above, 1a is a smoke detector,
4 is a line voltage detection circuit section, 5 is a switching circuit section, 6 is a high-sensitivity relay, 7 is a first timer circuit section, 8 is a second timer circuit section, 9 is a malfunction prevention circuit, r ₀ is a relay contact, Ry ₁ ~ Ry _o is receiving relay, l ₁
~ _lo is a sensor connection line, l _c is a common line, r ₁₁ ... is a changeover switch, Th is a transistor, C ₁ ... is a capacitor, and R ₁ and R ₂ are resistors.

Claims (1)

[Scope of utility model registration request] A line state detection means that generates an output when the voltage applied between the common line and the sensor connection line that constitutes the sensor line or the line current of the sensor line changes to a predetermined level, and the sensor connected to the sensor line. a switching circuit unit that uses the detection output of the line state detection unit to drive a switching unit whose operation time is shorter than that of the receiving relay that operates in response to the operation of the line state detection unit; and a time-limited operation that starts from the start of operation of the switching circuit unit. a first timer circuit section that sets the switching circuit section in an on-operable state until a time-up occurs; and a second timer circuit section that sets the switching circuit section to an OFF state, and when the switching circuit section drives the switching means, the switching means opens the starting end of at least one of the sensor connection line and the common line. A fire alarm system is provided with a malfunction prevention circuit configured such that the malfunction prevention circuit is shared by a plurality of sensor lines. A resistor that provides a base bias is connected between the collector and base of the transistor, and between the base of the transistor and the negative line of the power supply line, the normally open side of the switch switched by the receiving relay corresponding to each line and a capacitor are connected. A malfunction prevention device for a fire alarm system, characterized in that a plurality of series circuits are connected in parallel according to the number of receiving relays, and a discharge resistor is connected between the normally closed side of each switch and a capacitor.