EP0066200A1 - Method and device for revision in a hazard, particularly a fire alarm system - Google Patents

Abstract

Revision procedure in a hazard detection system in which several different, individually identifiable detectors (M) are connected to a central office (Z) and are connected to an evaluation device (AW) with a cyclical interrogation device (LX). The detectors (M) can be switched on (RK) individually or in groups to a revision display (RD) without suppressing an alarm display (AD). A first message from a detector to be revised is evaluated and saved as a revision message (RD) and a message from the same detector that arrives afterwards is evaluated and displayed as an alarm message (AD). For detectors that emit multi-stage or analog signals, the detector signals are evaluated in the control center (Z) with two threshold value circuits (SWO, SWA and SWU, SWR). During the revision, a revision message (RD) is recognized either for less sensitive detectors with the lower threshold value level (SWU), or if the detector sensitivity for alarms with a lower test medium remains unchanged, a revision message is generated and recognized with the revision threshold (SWR).

Description

The invention relates to a method for revision in a hazard, in particular fire alarm system, in which several detectors are connected to a control center, in which the individual detectors can be connected to an evaluation device with a cyclical interrogation device.

In order to ensure the safe functioning of fire alarm systems, it is mandatory to check all system parts at regular intervals. On the one hand, the central modules are tested, on the other hand, the connected detectors are triggered, whereby detectors and transmission routes to the control center are checked. In general, it is customary in the fire alarm control center with a revision device not to evaluate the incoming messages from the detectors triggered for test purposes as a sharp alarm, but rather to register them as a revision message. Often these revision messages are automatically reset afterwards.

In conventional fire alarm systems, several detectors can be connected in parallel or in series to one alarm line. If a detector on this line is triggered, this causes a current change on the detection line, which is evaluated centrally as an alarm. There will be an alarm the line is recognized, whereby the alarming detector cannot be located in the control center. For detector revision, an entire detection line must therefore always be switched to the revision state. All messages that now come from this line are not evaluated as alarms, but as revision messages. In the event of a revision, depending on the number of detectors on the "in the revision status, a more or less large spatial area is no longer monitored, which represents a considerable security risk. This risk is reduced today because, in addition to the automatic detectors, they can also be triggered manually Detectors must be installed, but then they must not be connected to the same detection line as the automatic detectors, so that automatic and manual detection lines must never be switched to revision in the same spatial area at the same time, so that an alarm from the area is still possible .

For revision in a reporting area, for example, the line with the automatic detectors is switched to revision in the central. Then these detectors are checked. The line in the control center is then armed and the manually operated detectors, which have their own detection line, are switched to revision. Now the manual detectors are triggered and this line is then armed again. The maintenance technician must therefore walk through the same spatial area twice to trigger the different detectors. This means an increased expenditure of time. Another disadvantage is that, in the meantime, the switchover from one detection line to the other detection line has to be carried out in the control center for the same area, which leads to an additional expenditure of time, especially since the detection location and control center can generally be further apart.

The object of the invention is to provide a revision method which avoids the disadvantages indicated above and which allows a revision without suppressing the detection and further processing of alarms occurring during the revision. The method according to the invention is intended both in the case of conventional alarm systems, also with a plurality of detectors per line, which cannot be identified individually, and also in the case of modern hazard alarm systems, which allow the individual detectors to be identified and the multistage or analog detector signals to be evaluated at the control center, allow a revision.

This object is achieved in that the detectors are switched individually, in groups or in their entirety to a respective revision display without suppressing an alarm display, that a first message from a detector to be revised is assessed as a revision message and displayed that after a Revision message of the relevant detector is automatically reset after a predetermined time and the revision message that has been saved is saved, and that another message from the same detector is evaluated and forwarded as an alarm message.

With the revision method according to the invention, individual detectors, detector groups, detector lines or even the entire control center can be switched to revision. After that, the first message arriving from a detector in the revision state is always evaluated as a revision message and automatically reset after a predetermined time. However, the fact remains that the detector has already been revised. If another message comes from this detector during the revision period, this message is considered an alarm.

It is advisable to reset and re-activate a detector several times before a real alarm is recognized and forwarded. An alarm signal is only generated and displayed after a revised detector has been triggered several times. Real alarms cannot be lost even after repeated resets, as automatic detectors always respond as long as the fire parameter is available. Manually triggered detectors save the message mechanically until it is reset by hand.

A major advantage of such a revision procedure results from the fact that system parts no longer have to be taken out of operation, but that only real alarms are recognized and displayed somewhat later. So there is no reduction in security during the revision.

Another advantage of such a revision procedure is that automatic and manual detectors can be switched on the same line, which saves assembly costs, and that larger parts of the system can be switched to revision than before. In addition, different types of detectors, if they can be identified individually at the control center, can be triggered in any order, which considerably simplifies maintenance.

In hazard alarm systems with detectors that emit multi-stage or analog signals that are evaluated in the control center, it is advisable to make the detectors less sensitive and to separately evaluate and display the detector signals with two threshold value circuits provided in the central evaluation device. The threshold level for real alarms is higher than that Threshold value level for alarm signals that are to be assessed as revision signals. This means that the evaluation circuit has two threshold value circuits with an upper and a lower threshold value level, during which the detector to be revised emits a detector signal which is evaluated and displayed as a revision message. If a hazard parameter that should trigger a real alarm occurs on a detector during the revision, this is recognized in the control center with the upper threshold value level of the evaluation circuit and forwarded and displayed as a real alarm.

In an advantageous manner, the response sensitivity for an alarm message in the evaluation circuit of the control center can also remain unchanged if a second threshold value circuit is provided for a lower threshold value. During the revision of the detectors to be revised, a small amount of test medium can be applied, so that a signal is emitted that is below the alarm-triggering signal threshold. The lower threshold is triggered by this detector signal and recognized and displayed as a revision message. If a real danger nevertheless occurs during the revision, this is recognized by the detector, evaluated and displayed in the control center with the second threshold circuit, which has an upper threshold value, the normal alarm threshold value.

Arrangements for carrying out the method are described in more detail with the aid of circuit examples.

• Fig. 1 ein Schaltbeispiel eines Meldebereichs mit herkömmlicher Meldeanordnung,
• Fig. 2 ein Schaltbeis^piel eines Meldebereichs mit einer erfindungsgemäßen Melderanordnung,
• Fig. 3a bis 3d verschiedene Meldermeßwert-Diagramme,
• Fig. 4 ein erfindungsgemäßes Schaltbeispiel mit einer Revisionsschaltung,
• Fig. 5 ein erfindungsgemäßes Schaltbeispiel mit zwei Schwellwertschaltungen in der Auswerteeinrichtung mit erhöhter Alarmschwelle und
• Fig. 6 ein erfindungsgemäßes Schaltbeispiel mit zwei Schwellwertschaltungen in der Auswerteeinrichtung mit unveränderter Alarmschwelle.

Show

• 1 is a circuit example of a detection area with a conventional detection arrangement,
• Fig. 2 is a Schaltbeis ^p iel a message area with an inventive detector arrangement,
• 3a to 3d different detector measured value diagrams,
• 4 shows a circuit example according to the invention with a revision circuit,
• 5 shows a switching example according to the invention with two threshold value circuits in the evaluation device with an increased alarm threshold and
• 6 shows a switching example according to the invention with two threshold value circuits in the evaluation device with an unchanged alarm threshold.

1 shows an example of a detection area with a conventional detection arrangement. An alarm line L1 runs from the area to be monitored to the control center. Several automatic detectors MA1 to MAn are connected to this detection line L1. As already mentioned at the beginning, in such a case it is necessary to provide a further detection line L2 in addition to this detection line L1. For example, this can have manually operable detectors MM1 to MM3 to a lesser extent than automatic detectors MA. If the L1 alarm line is switched to revision, one of these manual MM detectors can be triggered manually in the event of a sudden danger. Conversely, if the manually operable detectors MM are switched to revision, an actually occurring danger can cause one of the automatic detectors MA to respond and thus lead to an alarm display.

In the revision method according to the invention, the automatic detectors MA to MAn and the manual detectors MM1 to MM3 can be on the same line, e.g. L1, as shown in Fig.2. In the revision according to the invention, an alarm message cannot be suppressed and cannot be lost.

As already explained above, it is evaluated and displayed as a delay only as an alarm message.

The detector measurement diagrams shown in FIGS. 3a to b illustrate the course of the detector measurement values MMW, plotted over time T, according to the revision method according to the invention, as will be explained in more detail using the switching example with reference to FIG.

The detector measured values MMW are monitored in the control center Z with an evaluation device AW (FIGS. 4 to 6). If, for example, the idle value MMW of the detector is above the alarm threshold SWA, a drop in the detector measured value MMW to or below the alarm threshold SWA, for example at time TA, causes an alarm A, as shown in FIG.

If a detector is switched to revision in accordance with FIG. 3b, the detector signal (MMW) which is briefly (t) released during the revision by the detector at time TR and which falls below the alarm threshold value SWA is evaluated as revision signal R and the revision message is displayed. After a certain time, e.g. at time To, the detector is automatically reset.

If, as illustrated in FIG. 3c, a real alarm occurs with a detector switched to revision, the idle value MMW _{o of} the detector drops below the alarm threshold SWA, for example, at time T1 and thereby initially causes a revision message R, which is displayed as such. After a certain time, eg T2 - T1, i.e. at time T2, the detector is automatically reset. If at this point in time T2 the detector measured value MMW is still below the alarm threshold SWA, this is recognized and displayed as alarm A. An alarm message is not lost during the revision, it is only displayed with a time delay.

3d illustrates the course of the detector measured value MMW with revision message R and subsequent real alarm A. The detector switched into revision is revised at time TR. As already explained, this means a brief (t) drop in the detector measured value MMW from the idle value MMW _o below the alarm threshold value SWA. After the time t, the detector measurement value MMW returns to its idle value MMW. The revision message R is displayed. This fact is in the revision circuit RS, as per. Fig.4 is still shown, saved. After a certain time, at time To, the detector is automatically reset. A later real alarm A of the already revised detector, for example at time TA, then immediately leads to a real alarm A according to the invention. If the detector measured value MMW falls below the alarm threshold SWA, an alarm A is displayed immediately.

In the case of an already revised detector, an alarm can be given immediately if there is a real alarm. It is no longer necessary to wait until all detectors within a certain area have been revised before only then activating the detectors in this area again.

4 shows a circuit arrangement according to the revision method according to the invention, in which each detector M is assigned a revision circuit RS. The detectors are connected to a control center Z via detection lines L. For example, several detectors, detectors M11 to M1n are connected to control center Z via detection line L1.

A plurality of detection lines L, for example L1 to Lm, are connected to the center Z. The incoming signals from the detectors M11 to Mmn are converted in a signal matching circuit SA for further processing. An evaluation circuit AW known per se, which has, inter alia, a threshold value circuit SW, scans the individual message lines L1 to Lm in succession via the line multiplexer LX and checks whether a message is present or not. A revision circuit RS is provided for each detector M, which is shown in detail in the circuit example for the detector M11 and is designated RS11. It is controlled by the evaluation circuit AW via the MX multiplexer known per se. In the switching example, a signal from a detector means a logic H signal at the output of the evaluation circuit AW. With the MX detector multiplexer, the revision circuits RS11 to RSmn are controlled in sequence. Each revision circuit RS is assigned a revision switch RK and a display diode for revision RD and a display diode for alarm AD. The revision display diodes RD11 to RDmn and the alarm display diodes AD11 to ADmn are each supplied with an H level, the revision switches RK11 to RKmn are each supplied with an L level. The revision circuit RS is explained in more detail below.

The revision circuit RS11 has a memory which is formed from two gates, a first NOR gate G1 and a second NOR gate G2. Downstream of the memory is a monoflop MF1, the first output Q of which leads to the first input of a first NAND gate G3 and the second output Q of which leads to the first input of a second NAND gate G4. The output of the NAND gate G3 leads to the alarm diode AD11 and the i output of the NAND gate G4 leads to the revision diode RD11. The detector signal is on the one hand at the first Input of the NOR gate G1, on the other hand to the respective second inputs of the two NAND gates G3 and G4. The first input of the second NOR gate G2 is supplied with an L level when the revision switch RK11 is switched on, as is the reset input R of the monoflop MF1. The output Q of the NOR gate G1 leads to the second input of the second NOR gate G2, the output Q of the second NOR gate G2 leads to the second input of the NOR gate G1 and to the input of the monoflop MF1. If the detector (M11) is switched to revision, the revision contact RK11 is closed. If there is an H signal from the detector M11 at the input of the revision circuit RS11, the memory, formed from the two NOR gates G1 and G2, is set and the subsequent monoflop} W1 is triggered. While the monoflop MF1 is running, the activation of the alarm diode AD11 via the NAND gate G3 is suppressed. Since the running time of the monoflop MF1 is selected to be longer than a revision message is normally pending, such a message only means that the memory G1, G2 is set, but the alarm diode AD is not activated. If there is a revision message, a revision message is displayed via the NAND gate G4 by the RD11 revision diode when the RK11 revision switch is switched on. A real alarm, on the other hand, takes longer than a short-term revision message, so that an alarm message is displayed on the alarm diode AD11 after the monoflop MF1 has expired. If, after the monoflop MF1 has elapsed, a second message from a detector arrives later, this is forwarded directly as an alarm message to the alarm diode AD11. If the detector M11 is armed, the revision switch RK11 is open and the memory, consisting of the two NOR gates G1 and G2, and the monoflop MF1 are reset. Messages from a detector then go directly to alarm display AD11 via NAND gate G3. The same applies to the others Revision circuits RS12 to RSmn.

If, as is customary in modern hazard alarm systems, the analog detector measurement values coming from the detectors are evaluated centrally, an upper and lower limit value can be set in an evaluation device according to the requirements if only two threshold value circuits are available.

5 shows a circuit example for a revision method in which the detectors are switched less sensitive. 5 is the same as FIG. 4 with respect to the line query LX. In contrast to FIG. 4, the evaluation device AW has two threshold value circuits SWO and SWU for an upper and a lower threshold value. A revision circuit RS as in FIG. 4 is unnecessary since a decision as to whether a revision message or an alarm message is present is made in the evaluation device AW. This means that the response threshold for the alarm is set higher during the revision, so that during the revision, the threshold circuit for the lower threshold SWU responds. This is recognized in the cyclic line scan LX with the lower threshold SWU. A parallel connection via the detector multiplexer MX leads from the respective output of the upper and lower threshold value switch SWO and SWU to a two-pole revision switch RK; shown in Figure 5 on the revision switch RK'11. This is connected in parallel to a pair of display diodes AD11 and RD11, so that for each detector M there is a display for the revision message RD and a display for the alarm message AD. If a real alarm occurs on a detector during the revision, the upper threshold SWO responds. In the event of a revision, the revision switch RK 'is switched over, that is to say in the position not shown, so that the alarm signal originates from the upper threshold SWO of the evaluation device AW comes to the alarm display AD. This is shown in the switching example for the M11 detector with the assigned switch RK'11 and the diode pair AD11 and RD11 (Fig. 5). During normal operation of the alarm system, the revision switch RK 'is in the position shown. The alarm threshold is again switched more sensitive, namely to the lower response threshold SWU. If a detector now responds, an alarm is displayed, ie AD responds.

With an arrangement according to the switching example in FIG. 5, it is also possible to proceed in such a way that the response threshold for the alarm as the upper threshold remains unchanged. For inspection purposes during the revision, the detectors to be revised are loaded with such a small amount of test medium that no alarm is given. However, in order to recognize a response of the detector, the threshold circuit for a lower threshold value is set so that it responds to the revision and can be displayed as revision message RD. This is shown in Fig.6. There are two threshold value circuits SWA and SWR in the evaluation device AW. The SWA threshold circuit responds to a detector alarm (alarm threshold). This is indicated by the detector multiplexer MX on the alarm diode AD assigned to the respective detector M (in the drawing e.g. AD11 for the detector M11). During the revision, the respective revision message display RD is switched on with the revision switch RK, so that during the revision with a small amount of test medium, the threshold circuit SWR (revision threshold) responds and the revision display RD is activated (in the drawing RD11 and RK11).

The exemplary embodiments shown and described can be implemented much more easily with a microcomputer in a signaling system with central evaluation with little effort.

Claims (8)

1. Procedure for revision in a hazard, in particular fire alarm system, in which several
Detectors are connected to a control center, in which the individual detectors can be connected to an evaluation device with a cyclical interrogation device, characterized in that the detectors (M) are switched individually, in groups or in their entirety to a respective revision display (RK) without that an alarm display is suppressed, that a first message from a detector to be revised is evaluated and displayed as a revision message (RD), that after a revision message, the detector in question is automatically reset after a specified time (MF1) and the revision message that has been saved is saved (G1, G2 ), and that another message from the same detector is evaluated and forwarded as an alarm message (AD). 2. The method according to claim 1, characterized in that after a revision message the detector in question is reset, is repeatedly reset after further messages and an alarm message is only forwarded after repeated response. 3. The method according to claim 1, characterized in that during the revision, the multi-stage or analog detector signals emitting detectors in the control center (Z) are switched less sensitive, that the respective revision signal is smaller than the respective detector signal in the event of an alarm, and that with two threshold circuits ( SWO, SWU) different threshold value levels, different types of detector signals are evaluated and displayed separately (RD, AD). 4. The method according to claim 1, characterized in that during the revision, the multi-stage or analog detector signals emitting detectors with unchanged response sensitivity are subjected to such a small amount of test medium that a detector signal is emitted which is below the alarm triggering signal threshold, and that with two threshold value circuits (SWO, SWU) of different threshold value levels different types of detector signals are evaluated and displayed separately (RD, AD). 5. Arrangement for performing the method according to claim 1, characterized in that in the control center (Z) for each detector (M) with a revision switch (RK) can be switched on. Revision circuit (RS) is provided which has a memory (G1, G2 ), a time delay circuit (MF1) and logic switching elements (G3 and G4), which are followed by a revision and alarm display device (RD, AD), the respective revision circuit (RS) in a manner known per se using a multiplexer (MX) to which the detector common evaluation circuit (AW) can be connected. 6. Arrangement according to claim 5, characterized in that the memory provided in the revision circuit (RS) of two NOR gates (G1 and G2), the time delay circuit is formed by a monoflop (MF1) connected downstream of the memory and the two logic switching elements of two NAND gates (G3 and G4) downstream of the monoflop (MF1) are formed. 7. Arrangement for performing the method according to claim 3, characterized in that in the control center (Z) the detectors (M) common evaluation device (AW) two threshold value circuits (SWO and SWU), one for an upper and one for a lower threshold value, which is connected in parallel in a manner known per se with a multiplexer (MX) to a revision switch (RK ') assigned to each detector with a subsequent revision and alarm display device (RD, AD) can be switched on. 8. Arrangement for performing the method according to claim 4, characterized in that in the control center (Z) the detectors (M) common evaluation device (AW) two threshold value circuits (SWA and SWR), one for an alarm threshold and one for a revision threshold, which can be connected in parallel in a catfish known per se with a multiplexer (MX) to each revision and alarm display device (RD, AD) assigned to each detector, a revision switch (RK) being assigned to the respective revision display device (RD).

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