GB2045495A

GB2045495A - Testing alarm systems

Info

Publication number: GB2045495A
Application number: GB8006370A
Authority: GB
Original assignee: Sachs Systemtechnik GmbH
Current assignee: Sachs Systemtechnik GmbH
Priority date: 1979-03-08
Filing date: 1980-02-26
Publication date: 1980-10-29
Also published as: GB2045495B; IT1129407B; IT8053014V0; FR2451072A1; IT8067357A0; DE2909112A1; JPS55124889A

Abstract

An alarm system, more especially for motor vehicles, is provided with at least one audible or visual alarm unit (11), at least one alarm indicator (1) and an alarm control (3-9 etc.) which responds to alarm triggering signals emitted by the alarm indicator and which thereupon energises the alarm unit. A test control stage (13), which is connected to a switch (15), gives upon the actuation of the switch (15) a simulated alarm triggering signal to the control path (5, 7) of the alarm control, which energises the alarm unit (11). The alarm control (29, 29) disables the alarm unit (11) in response to alarm triggering signals emitted by the control stage (13) and triggers an audible and/or visual monitor (35, 37) via the control path (5, 7) of the alarm unit <IMAGE>

Description

SPECIFICATION Alarm system The invention relates to an alarm system, more especially for motor vehicles, which is provided with at least one audible or visual alarm unit, at least one alarm indicator and an alarm control which responds to alarm triggering signals given by the alarm indicator and which thereupon energises the alarm unit.

The control path via which the alarm triggering signals energise the alarm unit comprises a plurality of components, for example input amplifiers, clock generators, relays, etc., each of which has to function in the event of an alarm. On conventional alarm systems, all that is monitored is whether the alarm system is activated or deactivated. It is not possible to check the functional efficiency of the individual components of the alarm control, so that technical defects or incorrect operations are not detected.

It is the object of the invention to indicate an alarm system which allows technical defects of the alarm control components, which are only put into operation in the event of an alarm, to be also detected and these components to be checked for their functional reliability.

Starting out from the alarm system illustrated in detail at the beginning, this problem is solved according to the invention in that a control stage connected to a switch emits, when the switch is actuated, an alarm triggering signal to the control path of the alarm control which enables the alarm unit, and in that in response to alarm triggering signals emitted by the control stage, the alarm control disables the alarm unit and triggers through the control path of the alarm unit an audible and/or visual monitor.

In contrast to the alarm triggering signals emitted by the alarm indicators, the control stage supplies a "simulated" alarm triggering signal which energises the monitor through the same control path through which the alarm indicator alarm triggering signals energise the alarm unit in the event of an alarm.

The monitor indicates the functional reliability of the control path of the alarm control, since it is only triggered when the control path functions reliably.

The alarm unit may be the horn and/or the headlight flasher of the motor vehicle; there may be used, for example, door contacts, vibration indicators, etc. as the alarm indicators. The switch is preferably a switch which also controls the functional readiness of the alarm control and by means of which the alarm system can be activated or deactivated.

Suitable are key switches, more especially magnetic key switches; however, it is also possible to provide test keys, by way of addition if required.

Following an alarm, the alarm system should be automatically de-energised after the expiration of a total period of connection. For this purpose, there may be connected into the control path of the alarm control a time control which fixes the total period of connection of the alarm unit following the appearance of an alarm triggering signal. The total period of connection of this time control is relatively long and is, for example, 30 seconds. In a preferred constructional form, there is therefore provided for the control of the monitor a second time control, whose total period of connection is shorter than the total period of connection of the first time control. The total period of connection of the second time control is preferably approximately 2 to 4 seconds, but more especially 3 seconds.

In order to increase the signalling effect of the alarm unit as well as that of the monitor, the first time control and/or the second time control energise(s) and de-energise(s) the unit associated therewith periodically during the total period of connection.

By suitable circuitry measures it can be ensured that the monitor produces different signals in dependence on the functional state of the alarm system or in dependence on the nature of the alarm control defect that has occurred. In this way, it is possible to detect or avoid incorrect operations of the alarm system or else the nature of the defect in the alarm control can be identified. It has proved to be expedient if the second time control, either in response to the alarm triggering signal produced when the switch is switched on or in response to the alarm triggering signal produced when the switch is switched off, energises the monitor continuously for the total duration of connection and, in response to the alarm triggering signal produced during the respective other switching operation of the switch periodically energises and de-energises it.In this way, it is possible to inform the user of the alarm system of the operational state of the alarm system foilowing the actuation of the switch.

Since the functional check does not involve the alarm unit proper, the alarm unit is preferably disabied through a de-energising stage which is controllable by the second time control and is expediently connected directly before the alarm unit. The de-energising stage may be a relay or the like.

The control stage is preferably designed as an automatic line controller stage for the lines leading to the switch.

An exemplified embodiment of the invention will hereinafter be explained in more detail with reference to a drawing. The drawing shows a block circuit diagram of an alarm system for a motor vehicle.

The alarm system comprises several alarm indicators 1, for example door contacts or vibration indicators, which are connected through a trigger stage 3, if necessary several trigger stages, to a circuit logic 5. The trigger stage 3 converts the signals or the edges of these signals emitted by the alarm indicators 1 into pulses which are processed in the circuit logic 5 together with other signals determining the function of the alarm system.

The circuit logic 5 defines whether the signals fed thereto denote an alarm or not. In the event of an alarm, the circuit logic 5 emits a signal-to a time control 7 which, for its part, connects through a relay stage 9 the alarm unit, for example a horn 11 of the motor vehicle, to the operating voltage source V+, for example the vehicle battery. The time control 7 periodically energises and de-energises the horn 11 through the relay stage 9 for a predetermined period, for example 30 seconds, at a frequency of, for example, 2 Hz.

In order to activate or de-activate the alarm system, the circuit logic 5 is connected through an automatic line controller 1 3 to a latch 1 5. The automatic line controller 1 3 monitors the lines 17, 1 9 leading to the latch 1 5. The circuit logic 5 evaluates the signal which has been fed through a line 21 from the automatic line controller 1 3 and which corresponds to the functional state of the lines 17, 1 9 so that it can be displayed in a manner which will be explained hereinafter.

The alarm triggering signals emitted by the alarm indicators 1 are processed substantially in the control path of the horn 11 which is formed by the circuit logic 5 and the time control 7. In order to be able to check the functional efficiency of this control path, the automatic line controller 1 3 emits upon the activation or de-activation of the alarm system by means of the latch 1 5 a "simulated" alarm triggering signal through a line 23 to the circuit logic 5 which thereupon triggers the time control 7 in accordance with the alarm triggering signals fed from the alarm indicators 1.If the time control 7 starts to work properly, then there is triggered through a line 25 another time control 27 which blocks the relay stage 9 of the horn 11 through a line 29 for a predetermined period, for example 3 seconds, so that the horn 11 does not respond. After the expiration of its preset time duration, the time control 27 de-energises the time control 7 through a line 31. The time control 27 moreover controls a relay stage 33 which, during the predetermined time duration of the time control 27, connects checking equipment such as a buzzer 35 and a warning lamp 37 to the vehicle battery V+. The buzzer 35 and the warning lamp 37 are only triggered if the control path of the horn 11, formed by the circuit logic 5 and the time control 7, is functionally efficient.Over and above this, it is indicated whether the automatic line controller 13 and the latch 15 function properly since, if this is not the case, the circuit logic 5 does not respond properly.

The circuit logic 5 detect whether the alarm system is activated or de-activated. In order to identify the operational state of the alarm system from the nature of the signals produced by the buzzer 35 and the warning lamp 37, the information corresponding to the operational state of the system is fed through a line 39 to the time control 27. If the alarm system was activated by actuation of the latch 15, then the time control 27 periodically energises and de-energises the buzzer 35 and the indicator lamp 37 for the entire period of connection. If the alarm system was deactivated, then the time control 27 emits a continuous signal.

In order to be able to check the functional efficiency of the alarm system independently of the operational state, the circuit logic 5 is connected to a checking key 41, via which there can be produced a "simulated" alarm triggering signal similar to the simulated alarm triggering signal emitted by the automatic line controller 13.

In addition to the control path of the horn 11 monitored by the time control 27, nonmonitored control paths may be connected to the circuit logic 5. A relay stage, which is connected to the circuit logic 5 and to whose connection 43 there is connected the motor vehicle ignition system to be short-circuited in the event of an alarm, is designated 45.

Claims

1. An alarm system, more especially for motor vehicles, which is provided with at least one audible or visual alarm unit, at least one alarm indicator and an alarm control which responds to alarm triggering signals emitted by the alarm indicator and which thereupon energises the alarm unit, characterised in that a control stage (13), which is connected to a switch (15), gives upon the actuation of the switch (1 5) an alarm triggering signal to the control path (5, 7) of the alarm control, which energises the alarm unit (11) and in that the alarm control disables the alarm unit (11) in response to alarm triggering signals emitted by the control stage (13) and triggers an audible and/or visual monitor (35, 37) via the control path (5, 7) of the alarm unit (11).

2. An alarm system as claimed in Claim 1, characterised in that the control path (5, 7) of the alarm control comprises a first time control (7) which fixes the total duration of connection of the alarm unit (11) following the appearance of an alarm triggering signal and in that for controlling the monitor (35, 37) there is provided a second time control (27), whose total duration of connection is shorter than the total duration of connection of the first time control (7).

3. An alarm system as claimed in Claim 2, characterised in that the first (7) and/or the second (27) time controls periodically energise and de-energise the units (11, 35, 37) during the total period of connection.

4. An alarm system as claimed in Claim 2 or 3, characterised in that the second time control (27) continuously energises the monitor (35, 37) for the entire period of connection either in response to the alarm triggering signal produced when the switch (15) is switched on or in response to the alarm triggering signal produced when the switch (15) is switched off and periodically energises and de-energises it in response to the alarm triggering signal produced during the respective other switching operation of the switch (15).

5. An alarm system as claimed in Claim 2, characterised in that the alarm unit (11) is connected to the control path (5, 7) through a de-energising stage (9) which is controllable by the second time control (27).

6. An alarm system as claimed in Claim 1, characterised in that the control stage (13) is designed as an automatic line controller stage for the lines (17, 19) leading to the switch (15).

7. An alarm system as claimed in Claim 1, characterised in that the switch (15) is designed as a latch.

8. An alarm system as claimed in Claim 1, characterised in that the switch (15) moreover controls the functional readiness of the alarm control.

9. An alarm system as claimed in Claim 1, characterised in that a checking key (41) as well as the switch (15) trigger the monitoring functions.

1 0. An alarm system substantially as described with reference to the accompanying drawings.