EP0602570A1 - Alarm system - Google Patents

Abstract

A plurality of DC-monitored primary detector lines with in each case a plurality of alarm detectors and a line terminating resistor are connected to a central station, the resistance value being measured and evaluated for each primary detector line. A plurality of detectors (M11,M12,...) are combined to form a detector group (MG1), and a plurality of detector groups (MG1,MG2) are connected to a primary detector line (MPL), by arranging in series in the primary detector line (MPL) a group resistor (R1,R2,...), which has in each case another resistance value, for each detector group (MG1,MG2,...), and by connecting the detectors (M11,M12,...), connected in series, of a detector group (MG1,...) in parallel with the corresponding group resistor (R1,...). When a detector (M11,...) has been triggered, the central station (Z) indicates the corresponding detector group (MG1,...). Respective detector-sabotage contacts (S11,S12,...) are arranged as break (open) contacts in the return line of the primary detector line (MPL). Another switching element, for example an acknowledging element (QE), can be connected instead of the detector group to one of the group resistors of a primary detector line. <IMAGE>

Description

The invention relates to a hazard alarm system with a control center, to which a plurality of DC-monitored primary alarm lines, each with a plurality of hazard alarms and a line terminating resistor, are connected, the resistance value being measured and evaluated for each primary alarm line.

In the case of intrusion or fire alarm systems that work on the principle of the DC primary monitoring line, the detectors of a primary reporting line can be combined into detector groups. When the primary reporting line is evaluated by a control center, the messages of the individual detector groups are then evaluated independently of one another in accordance with various specifications or the necessary regulations. Sabotage contacts in the detectors and distributors of a primary reporting line secure it against manipulation by unauthorized persons, although a separate reporting line is generally required.

The assignment of the detectors of a primary signal line to different detector groups with simultaneous connection of sabotage contacts has so far only been possible in systems that transmit the message information digitally. However, these digital systems are very complex.

In the less complex DC systems, only one detector group has been assigned to a primary signal line. Therefore, when forming many detector groups A great deal of effort is required with regard to the wiring of the individual primary reporting lines and the performance of the control center in accordance with the number of primary reporting lines to be connected. A DC-monitored hazard alarm system is therefore disproportionately expensive because considerable effort is required.

German Offenlegungsschrift 29 35 335 describes a direct current signaling system in which the conductor loop, i.e. the reporting primary line forms a resistance network, whereby the control center can identify a addressed detector by measuring the total resistance.

German Offenlegungsschrift 29 39 449 describes a direct current hazard alarm system in which alarm and sabotage detectors are connected to one and the same line (primary reporting line), the central unit evaluating and displaying alarms and sabotage independently of one another, but the individual detector cannot be identified is.

The object of the invention is to further develop such DC-monitored hazard alarm systems in such a way that several detector groups can be monitored and identified with one primary signal line, and that this primary signal line can be monitored for sabotage without additional lines.

This object is achieved according to the invention in a hazard alarm system described in the introduction in that several detectors are combined to form a detector group and several detector groups are connected to a primary detector line, with one for each detector group Group resistance, each with a different resistance value, is arranged in series in the primary signal line and the detectors of a detector group connected in series are connected in parallel to the associated group resistance, the central unit identifying and displaying the corresponding detector group when a detector is triggered, and that respective detector sabotage contacts are opening contacts are arranged in the return line of the primary signal line.

At the hazard detection system according to the invention, several hazard detectors are connected to a DC primary signaling line. A terminating resistor ensures a constant quiescent current. Several detectors are assigned to a group resistance and thus combined into one detector group. The group resistors each have different values to ensure unambiguous identification. Detectors can be issued in one zone independently of the other zones or simultaneously with it, with the quiescent current changing, i.e. the resistance value of the respective primary signal line monitored and measured in the control center is a criterion for triggering a detector or a sabotage contact. For this purpose, the sabotage contacts on the primary signal line are combined to form an independent sabotage and fault detector group. In particular, the tamper contacts of the detectors can be arranged as openers in the return line of the primary signal line between the control center and the terminating resistor.

The arrangement according to the invention has the advantage that with only a single primary signal line both a large number of detector groups can be identified individually and the primary signal line for sabotage or one a respective sabotage contact of the detectors can be monitored without additional wiring and with relatively few components.

In a further development of the invention, a different switching element is connected to a group resistance of the primary detector line instead of different detectors that form a group, which can be identified individually when activated and can signal a very specific state for this primary signal line. The other switching element connected in parallel with the group resistor can serve as an acknowledgment element for arming / disarming an intrusion detection system, in particular the relevant primary reporting line.

The alarm contacts of the detectors of a detector group connected in series are expediently designed as openers, which short-circuit the group resistance in the idle state. This means that the quiescent resistance of the primary signal line is essentially formed by the line terminating resistance and the resistance value of the signal line itself. In the event of an alarm, ie when a detector triggers, the relevant detector contact is opened and the associated group resistor is connected in series with the line terminating resistor. The resulting change in current is recognized by the control center as a reporting criterion, the alarm-triggering detector group being identified on the basis of the measured resistance value. Each possible total resistance of the primary signal line may only be caused by a single combination of group resistors and terminating resistors.

In an advantageous embodiment of the invention, the resistance value of the signaling primary line which is at rest is obtained in the control center when the hazard alarm system is put into operation by measuring, the resistance value determined being stored in a memory for later comparison purposes. In the same way, it is advantageous to measure the individual possible resistance values of the primary signal line by triggering a detector of a respective detector group and to store it in accordance with the triggering detector group. This also applies to the separate switching element, for example the receipt element.

In an expedient embodiment of the invention, further sabotage contacts can be connected in parallel to the primary signal line as make contacts, for example in junction boxes. These sabotage contacts can be arranged in front of, between or behind a respective group resistor, so that a plurality of line sections is formed which, in the event of sabotage, can be identified on the basis of the differently measured resistance values.

• Fig. 1 eine Gefahrenmeldeanlage mit Zentrale und einer Meldeprimärleitung mit beispielsweise lediglich zwei Meldergruppe ohne Sabotagekontakte,
• Fig. 2 eine Meldeprimärleitung mit zwei Meldegruppen und Sabotagekontakten und
• Fig. 3 eine Meldeleitung mit zwei Meldegruppen und einem Quittungselement, ebenfalls mit Sabotagekontakten.

The invention is briefly explained below with reference to the drawing. Show

• 1 shows a hazard detection system with a control center and a primary reporting line with, for example, only two detector groups without sabotage contacts,
• Fig. 2 is a primary reporting line with two zones and sabotage contacts and
• Fig. 3 shows a signaling line with two message groups and an acknowledgment element, also with sabotage contacts.

1 schematically shows a control center Z with a single reporting primary line MLP with two reporting groups MG1 and MG2. The primary signal line is terminated with the resistor RA. For each detector group MG1, MG2, a group resistor R1 and R2 is connected in series in the primary signal line MPL. The respective detector groups MG1 and MG2 are parallel to this, the individual detectors M11 to M13 of a detector group with their alarm contacts A1, A2, ... being connected in series. As shown in this exemplary embodiment, the resistor R1 can have 1 kΩ, the resistor R2 can have 2 kΩ and the line terminating resistor RA can have 0.5 kΩ. This results in the following resistance combinations for the resistance value of the signaling primary line MPL, which is measured and evaluated in the control center Z:
The signaling primary line is at rest, ie the resistance value is 0.5 kΩ, whereby the actual line resistance is not taken into account. A detector in detector group MG1 has triggered, that is, an alarm contact A1 to A3 in this group has opened, so that resistor R1 is in series with resistor RA. This results in a resistance value of 1.5 kΩ. If a detector from detector group MG2 has triggered, the resistance value is 2.5 kΩ (R2 + RA). If a detector has triggered in both detector group MG1 and MG2, the resistance value is 3.5 kΩ (R1 + R2 + RA). The alarm status of the individual detector groups can thus be clearly identified.

2 also shows a central station Z with only one primary signal line, but with a number of sabotage contacts. Each detector has a tamper contact S11, S12 etc. to S22, which is in the detector is arranged and is in the return line of the primary signal line MPL. There are also additional sabotage contacts SV1, .. SV4, which are arranged, for example, in junction boxes V1, V2, ... The sabotage contact SV4 is arranged in series in the primary signal line MPL as a break contact, which therefore interrupts the signal line when actuated. The other three distribution box sabotage contacts SV1 ... SV3 are arranged in parallel to the terminating resistor RA in the signaling primary line MPL and are designed as make contacts, which close when actuated, so that a "short circuit" is measured in the central unit Z if the actual resistance value of the signaling primary line is disregarded leaves. The identification of the "sabotage" state, triggered by the SV1-4 closings, takes place in that the part of the line in which Ra is located is short-circuited by these switches. The alarm criterion is the lack of the characteristic resistance Ra in the measured total resistance of the signaling primary line (in the example: Ra = 0.5 kΩ). A wide variety of resistance combinations for alarm-triggering detectors can be obtained by the control panel measuring both the resistance of the primary primary line as well as the individual possible total resistances (terminating resistance and group resistances and associated line resistances) .To do this, at least one detector must be triggered in each detector group . The various resistance values can be saved and used for comparison when evaluating the measured resistance values.

In FIG. 3, in addition to two detector groups MG1 and MG2, an acknowledgment element QE is also arranged in the message primary line MPL, which has an acknowledgment element resistor RQ in the row of the message primary line MPL and one in parallel with it Switching contact KQ, which is closed at rest, has. The feedback line has a tamper contact SQ in the acknowledgment element QE, which is also designed as a break contact. Since an opening of the contact KQ is not only registered in the control center Z, but is uniquely assigned to the receipt element QE, such an receipt element can
can be used, for example, to ensure that in an intrusion detection system that is prepared for arming, this arming element is finally brought into or kept in the arming state when leaving the house. This is particularly advantageous in intruder alarm systems, since no extra line has to be laid from an acknowledgment switch to the control center.

Claims (8)

Hazard detection system with a control center to which a number of primary detector lines monitored by direct current, each with a plurality of hazard detectors and a line terminating resistor, are connected, the resistance value being measured and evaluated for each primary reporting line,
characterized in that several detectors (M11, M12, ...) are connected to form a detector group (MG1) and several detector groups (MG1, MG2) are connected to a primary signal line (MPL) by for each detector group (MG1, MG2, .. .) a group resistor (R1, R2, ...), each with a different resistance value, is arranged in series in the primary signal line (MPL) and the detectors (M11, M12, ...) connected in series of a detector group (MG1, .. .) are connected in parallel to the associated group resistor (R1, ...), the control center (Z) identifying and displaying the corresponding detector group (MG1, ...) when a detector (M11, ...) has been triggered, and that each Detector sabotage contacts (S11, S12, ...) are arranged as opening contacts in the return conductor of the primary signal line (MPL). Hazard detection system according to claim 1,
characterized in that no detector group, but another switching element is connected to one of the group resistors of a primary signal line. Hazard detection system according to claim 2,
characterized in that the other switching element is designed as an acknowledgment element (QE) for arming / disarming. Hazard detection system according to one of the preceding claims, characterized in that
that the series-connected detectors (M11, M12, ...) of a detection group (MG1, ...) have detector contacts (A11, A12, ...) designed as NC contacts, which in the idle state have the group resistance (R1, ... ) short circuit. Hazard detection system according to one of the preceding claims, characterized in that
that each possible resistance value of the primary signal line is formed only by a single combination of group resistors and the terminating resistor. Hazard detection system according to claim 1,
characterized in that further tamper contacts (SV1, SV2, ...) are connected in parallel to the signaling primary line (MPL) as normally open contacts in junction boxes (V1, V2, ...), in the monitored line sections in front of or behind a group resistor (R1, R2, ...) are arranged. Hazard detection system according to one of the preceding claims, characterized in that
that the resting resistance value is obtained and measured in the control center when the hazard alarm system is started up. Hazard detection system according to one of the preceding claims, characterized in that
that the individual possible resistance values of the primary signal line are obtained and recorded by triggering a detector of a respective detector group or a separate switching element.

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