JPS6319094A - Fire alarm - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention detects an abnormality in a line drawn out from a receiver to a terminal side to prevent malfunctions of terminal units such as detectors and repeaters. Regarding the fire alarm system.

(Prior Art) Conventionally, as this type of fire alarm device, the one shown in FIG. 2, for example, is known.

In FIG. 2, 1 is a receiver, and a pair of power and signal lines (hereinafter simply referred to as 1 line) 2a and 2b led out from the receiver 1 are connected to a terminal unit 3 such as a sensor or a repeater.
A, 3b, . . . are connected in parallel, and the terminal units 3a, 3b, . , a latch circuit, etc. are provided.

Further, a main circuit 4 is provided within the receiver 1, and employs a polling method, for example, to sequentially call the terminal units 3a, 3b, . . . and transmit fire data, and the terminal units 3a, 3b, . The CPU provided in the main circuit 4 makes a fire judgment based on the fire data sent from the main circuit 4.

(Problems to be Solved by the Invention) However, in such a conventional fire alarm device, the lines 2a and 2b drawn out from the receiver 1 to the terminal side
If a momentary short circuit occurs between the terminal units 3a and 3b and the power supply to the terminal units is momentarily cut off, the terminal units 3a and 3b
There was a problem that the CPU installed in ... would run out of control.

In other words, the CPUs installed in the terminal units 3a, 3b, etc. are supplied with power from the receiver 1 via a backup container, but the power supply may be cut off due to a momentary short circuit. Due to a momentary power outage, the charging voltage of the backup capacitor drops to near the operating point of the CPU, and the CPU operation becomes unstable, causing the CPU to run out of control. Since the voltage has not fallen to the level where an initial reset is applied, the initial reset will not be applied to the CPU when the power supply voltage rises when the power is restored.
There was a problem where the CPU was left running out of control.

(Means for Solving the Problems) The present invention has been made in view of such conventional problems, and is designed to prevent line abnormalities such as instantaneous short circuit accidents on the line drawn out from the receiver to the terminal side. To provide a fire alarm device which can surely prevent malfunctions such as runaway of a CPU provided in a terminal unit such as a detector or a repeater even if a fire alarm occurs.

In order to achieve this object, in the present invention, a switch means is inserted and connected between the receiver main circuit and the terminal line, and when a line abnormality such as a short circuit accident of the terminal line is detected by the line abnormality detection means, control is performed. The circuit turns off the switch means for a certain period of time during which initial reset can be applied to the terminal.

According to the configuration of the present invention, when a momentary short-circuit accident occurs on the terminal line and a momentary interruption of the power supply voltage to the terminal unit occurs, the abnormality detection means provided in the receiver detects whether the line is short-circuited or not. When an abnormality is detected, the control means turns off the switch means for a certain period of time to cut off the power supply to the terminal unit, and this interruption of the power supply for a certain period of time charges the backup capacitor provided in the terminal unit. The voltage drops to approximately 200 volts, and when the switch means returns to the on state after a certain period of time and the power is restored, the CPU is reliably initialized in the same way as when the power is first turned on in the receiver, preventing a momentary power outage. Even if this occurs, malfunctions due to cPU runaway can be reliably prevented.

(Example) FIG. 1 is a block diagram showing one embodiment of the present invention.

First, to explain the configuration, 1 is a receiver, and a pair of lines 2a are drawn out from the receiver 1 to the terminal side.

A plurality of terminal units 3a, 3b, . . . consisting of sensors, repeaters, etc. are connected in parallel between 2b.

For example, if these terminal units 3a, 3b, etc. are detectors, the temperature, smoke concentration, and C
Analog sensor (- detects O gas concentration etc., receiver 1
C that sends analog detection data upon receiving a call from
A PU is built in, and the repeater includes a CPU that receives a call from the receiver 1 and sends out a detection signal from a sensor connected to a sensor line from the repeater.

A main circuit 4 is installed in the receiver 1, and the main circuit 4 includes a power supply circuit that supplies a power supply voltage between the lines 2a and 2b led out to the terminal side, and terminal units 3a and 3b.
A CPU or the like is provided that executes fire judgment processing based on data transmitted from . A switch element 5 is inserted and connected between this main circuit 4 and one of the -6= lines 2a led out to the terminal, and as this switch element 5, for example, an analog switch using an FET is used.

Furthermore, an abnormality detection circuit 6 is provided within the receiver 1 . The abnormality detection circuit 6 includes a detection section that detects a short circuit occurring between the lines 2a and 2b, and a determination section that determines the short circuit detection time. The determination unit determines whether the short circuit time is a momentary short circuit, distinguishes between a momentary short circuit and a continuous short circuit, and sends an abnormality detection output due to a momentary short circuit and a continuous short circuit to the control circuit 7. It is sent separately from the abnormality detection output.

The control circuit 7 includes a determination section that determines whether the abnormality detection output is due to an instantaneous short circuit or an abnormality detection output due to a continuous short circuit, and a timer section that counts a certain period of time by determining whether the abnormality detection output is due to an instantaneous short circuit. We are prepared. When the control circuit 7 determines that the abnormality detection output is a continuous short circuit,
A control signal for switching the switch element 5 to the off state is output to the drive circuit 8. If it is determined that the abnormality detection output is due to a momentary short circuit, a control signal to turn off the switch element 5 is output to the drive circuit 8, and when the timer section finishes counting for a certain period of time, the switch element 5 is turned on. A control signal for switching the state is output to the drive circuit 8. This turns off the switch element 5 for a certain period of time. The switch off time that lasts for a certain period of time is the terminal unit 3a.

3b, . . . is set as a time that allows the CPU, flip-flop, latch circuit, etc. provided in . . . to be sufficiently initial reset.

Next, the operation of the embodiment shown in FIG. 1 will be explained.

Now, the lines 2a and 2b are drawn out from the receiver 1 to the terminal side.
If an instantaneous short-circuit accident occurs between The detecting section of the detecting circuit 6 detects the short circuit, and the determining section determines that the short circuit time is an instantaneous short circuit. The abnormality detection circuit 6 sends an abnormality detection output, which is a momentary short circuit, to the control circuit 7. The control circuit 7 outputs a control signal to the drive circuit 8 to switch the switch element 5 that is in the on state to the off state for a certain period of time while the timer section is abnormally activated for a certain period of time. In the event of a momentary short-circuit accident, the power supply to the terminal units 3a, 3b, . The Rukoto. Even if the power supply is cut off for a certain period of time and backup capacitors are installed in the terminal units 3a, 3b, . . . , the charging voltage of the capacitors will drop to approximately zero volts. The terminal units 3a, 3b, .
The power supply voltage will rise from approximately zero volts,
Terminal units 3a, 3b.

The CPU, flip-flop, latch circuit, etc. whose PH is set to φ... are surely initial reset in the same way as when the power is turned on by the receiver 1 for the first time, and it is possible to prevent the CPU, etc. from running out of control. On the other hand, if there is a continuous short-circuit accident between the lines 2a and 2b, the determination section of the abnormality detection circuit 6 determines that the short-circuit time is abnormal for a certain period of time, and the control circuit 7
Sends an abnormality detection output due to continuous short circuit. The control circuit 7 outputs a control signal to the drive circuit 8 to turn off the switch cable 5. Therefore, the switch element 5 remains in the off state.

In this case, when the switch element 5 is turned on, the switch element 5 may be configured to recover by pressing the button to repair a short circuit.

Further, in the above embodiment, short circuits and voltage drops caused by the main circuit 4 are detected by the abnormality detection circuit 6, but the lines 2a and 2b may be directly monitored by the abnormality detection circuit.

-10= (Effects of the Invention) As explained above, according to the present invention, even if a momentary short circuit occurs between the lines drawn out from the receiver to the terminal side, the abnormality detection provided in the receiver When the means detects a line abnormality due to a short circuit, the control means turns off the switch means to cut off the power supply to the terminal unit for a certain period of time, so that when the line abnormality is detected, the power supply is cut off for a certain period of time. The power supply voltage of the terminal unit drops to approximately zero volts, and when the switch means returns to the on state after a certain period of time and the power is restored, the CPU installed in the terminal unit is activated in the same way as when the power is first turned on in the receiver.
, flip-flops, latch circuits, etc. are reliably initialized, and even if a line abnormality occurs due to a momentary short circuit, malfunction of the terminal unit can be reliably prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional example. 1: Receiver 2a, 2b: Power supply signal line (line) 3a, 3b: Terminal unit 4: Child circuit 5: Switch element 6: Abnormality detection circuit 7: Control circuit 8: Drive circuit

Claims (1)

[Claims] In a fire alarm device in which terminal units such as a sensor and a repeater are connected in parallel between a pair of power supply signal lines led out from a receiver, a receiver main circuit and a receiver main circuit are connected in the receiver. A switch means inserted and connected between the lines, a line abnormality detection means for detecting an abnormality in the line, and when a detection output of the line abnormality detection means is obtained, the switch means is connected to the terminal unit for initial reset of the terminal unit. A fire alarm device characterized by being provided with a control means that turns off for a certain period of time.