JPS6320599A - Detector for 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 Field of Application) The present invention comprises a detector connected to a two-conductor loop, said loop connects a controller to said detector, and provides an alarm for supplying current to the detector. It is related to the device.

(Technical Background of the Invention) Such an alarm device includes, for example, a fire alarm. In this case, each detector detects, for example, smoke and generates an alarm signal, and the alarm signal is energizes the associated indicator light and activates an oscillator connected to the loop.Each detector also includes a fault signal generator.When a fault occurs in a detector, the fault signal associated with that detector is activated. The device works.

In this example, when smoke is detected and the detector is activated, the detector's oscillator injects a signal into the loop, which causes the detector's indicator light to illuminate. The signal sent by the oscillator is detected by the controller, and the activated detector can be identified by an illuminated indicator light.

The alarm system may include a device that detects a fault such as an open or short circuit in the loop feeding the detector. In order to increase the reliability of the alarm system, it is desirable to constantly monitor the sensors of the various detectors and to be able to generate a fault signal to the controller in the event of a fault in the detector itself.

[Conventional technology]

A fault signal generator is provided which, when actuated, opens the circuit of the loop such that a fault signal is obtained at the controller, such as in the case of a fault (open or shorted loop) in the loop. The device is known.

This device has several drawbacks. First, the controller cannot discern whether the loop or the detector has failed. Furthermore, even if it is found that a fault has occurred in a detector, in order to find the faulty detector, it is necessary to successively replace the detectors in use with new ones. Also, in the case of an open loop, the possibility of detecting other events is lost. In particular, since the detector is no longer powered, it is no longer possible to detect events such as a fire.

[Purpose of the invention]

It is an object of the present invention to obviate some or all of these drawbacks.

Another object of the invention is to provide a loop-connected system in which the notification of a fault in a detector to a controller does not prevent the notification of events detected by non-faulty detectors to the controller. The goal is to obtain an alarm system that is

Another object of the invention is to visually indicate a faulty detector.

Yet another object of the present invention is to provide a visual indication that can distinguish between event-activated detectors and faulty detectors.

SUMMARY OF THE INVENTION The present invention comprises a plurality of detectors, the detectors connected to a loop that includes two conductors that supply current to the detectors and that are connected to a controller that receives signals from the detectors. In said detector for alarm devices connected in parallel, event sensor means; alarm signal generation means responsive to said sensor means for generating an alarm signal and transmitting said alarm signal through said loop to said controller; fault signal generator means for generating a fault signal in response to the occurrence of a fault in the detector and transmitting the fault signal through the loop to the controller, the fault signal having a frequency distinguishable from the alarm signal; A detector for an alarm device is provided.

In this way, a fault occurring in the detector can be communicated to the controller without interrupting event detection. The ability to distinguish between frequencies allows the controller to react appropriately to events requiring alarm generation and to detector failures.

Advantageously, the indicator light means are connected to the fault signal generating means so as to respond to the fault signal.

By examining the detectors, a faulty detector can be found very quickly, so that it can be quickly replaced or repaired.

In a preferred embodiment of the invention, said indicator light means is connected to receive an output signal from said second oscillator. Since the frequency of the output signal is less than 10 Hz, the indicator light means is periodically illuminated in response to the fault signal. Thus, if a fault occurs in the detector, the indicator light will blink. The indicator light reacts differently to events, for example, it lights up continuously. Thus, a detector that responded to an event and a faulty detector are clearly and quickly identified.

〔Example〕

The alarm device shown in FIG. 1 has a controller 1. The alarm device shown in FIG. This controller feeds the two-conductor loop 2.

A plurality of detectors 3 are connected in parallel to the loop. Detector 3 includes special sensors that respond to specific events. For example, in the case of a fire alarm system, the sensors may include an ionization sensor for an ion detector and a dark sensor for an optical smoke detector. A two-conductor loop has two wires 4,5. These lines are connected to a DC power supply within the controller 1. For example, line 4 is connected to the positive terminal of the power supply and line 5 is connected to the negative terminal of the power supply.

In case of event detection, each activated detector 3 injects a low frequency signal into the loop 2. The signal is detected by the controller 1 and triggers, for example, a fire alarm. As will be explained later, each detector is associated with an indicator light. When the detector detects an event, its indicator light is illuminated. A low value resistor is inserted in the positive line 4 near the controller 1.

The resistor is used to detect the signal injected into the loop 2 by the detector and to detect changes in the strength of the current flowing through the loop 2, thereby making it possible to detect an open or short circuit of the loop 2. In particular, the loose ends of the two wires 4, 5 of the loop 2 are connected by an element 7, such as a low value resistor or an oscillator. In this example element 7 is an oscillator. Its element 7 makes it possible to distinguish the current flowing through the resistor 6 in case of a short circuit.

FIG. 2 shows the active electronics of a conventional detector. This active electronics includes an alarm signal generator. In the illustrated example, the alarm signal generator is a comparator 11 responsive to actuation of a sensor within the detector.
has. The alarm signal is stored in memory 12 and this stored signal controls low frequency oscillator 13. The output signal of that oscillator is injected into the loop 2 through a transistor ]4 connected between the positive line 4 and ground 5.

The alarm signal stored in the memory @12 controls the lighting of the indicator light 15 via the transistor 16.

In order to increase the reliability of such an alarm device, the device includes a monitoring device that constantly monitors the sensors of all detectors and indicates any faults that occur in the sensors.

The monitoring device includes a fault signal generator. In this example, the fault signal generator includes a comparator 17. The generated fault signal acts via the transistor 18 on the winding 19 of the normally closed relay and opens the contact 21 inserted in the loop 2. As previously mentioned, this prior art arrangement suffers from several drawbacks due to the disturbance signal opening the loop.

FIG. 3 shows the active electronics of the detector of the invention.

This detector has parts 11 to 16 similar to those of the detector shown in FIG. 2 for the alarm signal and a fault signal generator 17.
including.

In this embodiment of the invention, the fault signal is
1, and this stored fault signal controls the oscillator 32. The output signal of oscillator 32 is injected into loop 2.

The output signal of the oscillator 32 is passed through the OR circuit 33 to loop 2.
injected into. The OR circuit receives the outputs of the oscillators 13 and 32, generates an output signal, and controls the transistor 14 with the output signal.

In this embodiment, the lighting of the indicator light 15 can also be controlled by the fault signal. Advantageously, this control can be performed using the oscillator 32. The output signal of oscillator 32 is applied to one input terminal of OR circuit 34. An alarm signal stored in the storage device 12 is applied to another input terminal of this OR circuit. The output terminal of OR circuit 34 is connected to the base of transistor 160. Since the frequency of the output signal of the oscillator 32 is very low, less than lOHz, the indicator light 1
5 blinks when a failure occurs in the associated detector. In this way, just by looking at the detector, one can immediately tell whether the detector is in an alarm or fault condition.

The indicator light 15 can be composed of an electroluminescent diode as shown. In another embodiment, a double junction electroluminescent diode is used, one junction being controlled by a stored alarm signal and the other junction being controlled by a stored fault signal. In this variation, the OR circuit 34 is not required and visual identification of alarm and fault conditions of the detector can be accomplished by specific colors corresponding to the various conditions.

In the preferred embodiment, oscillator 32 has a frequency of 1 to 3
Generates a Hz square wave signal. This square wave signal effectively causes the indicator light 15 to blink.

[Brief explanation of drawings]

FIG. 1 is a wiring diagram of an alarm system including a detector powered by a two-conductor loop; FIG. 2 is a block circuit diagram of a conventional electronic detector; and FIG. 3 is a detector used in a preferred embodiment of the present invention. FIG. 2 is a block circuit diagram of the device. 1...Controller, 2...Loop, 3...Detector, 4
, 5... wire, 6... resistor, 11.17... comparator, 12°31... memory device, 15... indicator light, 3
2...Oscillator, 33.34...OR circuit.

Claims (10)

[Claims] (1) comprising a plurality of detectors, supplying current to the detectors,
The detector for an alarm device, wherein the detector is connected in parallel to a loop comprising two conductors connected to a controller receiving a signal from the detector, event sensor means;
alarm signal generation means for generating an alarm signal in response to the sensor means and transmitting the alarm signal to the controller through the loop; a fault signal generating means for sending the fault signal to the controller through the loop, wherein the fault signal has a frequency distinguishable from the alarm signal. (2) The detector according to claim 1, wherein the alarm signal generating means and the fault signal generating means each include a first oscillator and a second oscillator, and the oscillation frequencies of these oscillators are A detector with different characteristics. (3) A detector according to claim 2, characterized in that it includes indicator light means responsive to the alarm signal. (4) A detector according to claim 3, characterized in that said indicator light means is connected to said fault signal generating means and thereby responds to said fault signal. (5) A detector according to claim 4, wherein the indicator light means is connected to receive an output signal from the second oscillator, the frequency of the output signal being less than 10 Hz, and thereby A detector characterized in that said indicator light means is periodically illuminated in response to said fault signal. (6) The detector according to claim 5, wherein the indicator light means includes a logical OR circuit, and the OR circuit has an input terminal responsive to the alarm signal and an input terminal from the second oscillator. and an input terminal responsive to the output signal. (7) The detector according to claim 2, including signal injection means, the signal injection means being responsive to the first oscillator and the second oscillator to generate the alarm signal and the fault signal. Detector characterized in that a signal is injected into said loop. (8) The detector according to claim 3, wherein the indicator light means includes an electroluminescent diode. (9) The detector according to claim 8, wherein the electroluminescent diode has a first junction and a second junction, and the first junction is connected to the alarm signal generating means. a detector, wherein the second junction is responsive to the disturbance signal. (10) An alarm device comprising a plurality of detectors according to any one of claims 1 to 9, which are connected in parallel to the loop and connected to the controller.