DE19531081A1 - Wireless alarm installation, e.g. burglar alarm - Google Patents

Abstract

The evaluator and signaller can exchange wireless telegrams in both directions. The signaller receives a signal about instantaneous state changes of the evaluator, while it interrogates at least one auxiliary path or channel for presence of regular signals, instead of the main transmission path or channel. These signals are not completely evaluated and a state change is assumed, when nothing is available, or shape, or transmission frequency, or any other transmission parameters have been changed w.r.t. to such signals. Pref. the presence of a new signal is assumed from the presence of the carrier or selected data fields.

Description

Wireless alarm systems, e.g. B. Intrusion alarm systems have been around known for some time. These usually consist of a network driven evaluation unit - hereinafter referred to as the control center - and battery-operated detectors in the individual, to be secured Rooms as well as signaling devices connected to the control center such as Sirens. In the event of a message appearing, it will e.g. B. forwarded to the head office via radio, evaluated there and in Alarm triggered if necessary. The advantage of radio and battery operation is to avoid laying cables in the individual rooms.

The disadvantage here is the sending of messages in the un sharp state of the alarm system especially when moving report, since every start-up of the transmitter has a significant impact represents the load on the batteries and thus their lifespan shortens what a frequent exchange and therefore high operating due to costs.

To avoid the most serious disadvantages, the known Systems after a notification for a period of e.g. B. suppresses every further message for five minutes. This ent there is an insensitivity to real alarm messages during this period. Therefore, this period may only be a few Minutes.

For the reasons mentioned, it makes sense, also in the detectors to provide a receiving part for status information such as Transfer arm / disarm to the detectors. These can then Suppress unnecessary messages in the unset state and thus Save battery capacity.

Here, however, the problem arises that the recipient has a significant power consumption and therefore its constant Operation also unacceptably reduce battery capacity would. With an only temporary commissioning, however, could e.g. B. the important focus message is transmitted too late.

Even when commissioning the receiver only to certain, beforehand times agreed with the head office must at least stay in operation for a period of time to view the current data to be able to fully decrypt the telegram just to be able to most cases find that no new one - the notifier yet unknown - arming is present. In addition, the over path blocked during this time.

The invention is therefore based on the object on the detectors energy-saving way information about status changes such as B. the change from the "disarmed" state in the To transmit status "sharp".  

The problem is solved according to the invention by the additions described in claim 1 for detectors and control center, the function of which is described below:
Instead of using only one transmission channel, several transmission channels are provided, as well as a hardware and / or software-based device for recognizing the occupancy of a transmission channel.

These other transmission paths transmit independently of the path only status messages from the control center for the alarm messages. At Compliance with certain conventions is sufficient for the detector the information of the presence of a status message to the Confirmation of keeping the old system status win.

This means that the recipient only needs a short time at the agreed times to be put into operation to determine whether a new one Status message is present, e.g. B. by detection of the radio carrier or only certain data fields of the data telegram. So he will Significantly saved battery capacity.

No security deficit due to the reduced amount of data to let arise, for third parties secret or ver key agreements z. B. in the control software Detector and the control center are taken.

Through these agreements between the detectors and the headquarters the next one can be transferred from the head office with the status unchanged Status message used channel and time in one for unused authorized third parties to change in a way that is not understandable. It only the detectors and the control panel must each after the same channel change scheme. Is this scheme in In the event of a status change, the detectors will for example, carry out a regular status query or in change the safe state (e.g. "armed" state). in the the latter case would be the final decision on the next an alarm message was only made at the headquarters.

Such a radio alarm system is an example below wrote: motion detector and control panel are both with micro computers as well as with radio modules, which have a PLL (phase locked loop) one of 63 channels in the 434 MHz ISM Can select a band. Each module can send as well receive. Alarm messages are sent from the detectors to the sent to the reception center and from there on the same or reconfirmed on another channel. In the absence of reconfirmation e.g. B. due to interference, the message may be repeated or another interference-free channel on the part of the detector or the central selected.

To avoid unnecessary messages, the status is armed / disarmed transmitted on a dedicated radio channel. In a particularly advantageous embodiment of the invention is for the another channel that is particularly important for the Disarm message used.  

The notifier regularly asks both the Arming channel as well as the disarming channel on an existing radio carrier and compares the result with the internally saved state. In case of equality, the The receiver can be switched off immediately to save energy. Others if the complete data telegram is received and after real evaluation test evaluated. The internally saved state can then be adjusted accordingly.

The detector can thus set the motion messages on the armed Limit condition. Since usually none in this state Movements occur - otherwise the rare alarm would occur - will the number of reports is kept to a minimum. Without prejudice to this, the detector can, of course, in regular, then but further apart - e.g. B. every hour -, report its functionality to the head office.

Particularly advantageous, because for unauthorized third parties not without Seeing through further is using a regular changing instead of a static radio channel allocation as well regularly changing reporting times.

Another advantage of using multiple radio channels is that Possibility of testing the function of receivers and antennas both for the detectors as well as for the control panels. That would also be conceivable Query from third sources (radio services) for functional testing recipient.

Of course, the status messages are not on / off sharply limited, just as z. B. partial focus reports Inevitable closure message or alarm status messages be transmitted.

Furthermore, a forwarding of reports after this Procedures make sense, d. H. certain detectors can also combined perform the function of evaluation units.

Claims (10)

Main claim Sub-claims Subsidiary claims 1.Wireless alarm system or signaling system consisting of at least one evaluation unit and at least one detector which can exchange data telegrams with each other wirelessly in both directions, characterized in that a detector receives notification of upcoming changes in the status of an evaluation unit by regularly replacing the main transmission path or main channel at least queries an auxiliary path or auxiliary channel provided for this purpose for the presence of regular messages from the control center without fully evaluating these messages and, in the absence of or changed form or changed transmission frequency or changed other transmission parameters of this message, a change in state is assumed. 2. Plant according to claim 1, characterized in that for Determine the existence of a new message next only the presence or absence of the Carried out or selected data fields of the message is asked. 3. Plant according to claim 1, characterized in that the Detector depending on the state of the evaluation unit due to the received status messages in turn unnecessary messages suppressed to the headquarters. 4. Plant according to claim 1, characterized in that for important status messages of the evaluation unit for everyone important condition a separate or different transmission path or Radio channel or other modulation is used. 5. Plant according to claim 1, characterized in that min at least one detector also has at least one evaluation unit for contains the messages from other detectors. 6. Plant according to claim 1, characterized in that the Transmission by radio and for main and auxiliary channel different frequencies or modulations or Modulation Codes (CDMA) or Modulation Periods (TDMA) be used. 7. Plant according to claim 1, characterized in that a changing assignment of transmission paths or channels with possible consideration of reserve routes or reserve channels in the event of faults.   8. Plant according to claim 1, characterized in that for the Selection of the next auxiliary route or auxiliary channel, its use to maintain the current state signaled to the detector via a code not easily understandable for third parties Agreement between detectors and headquarters is made. 9. Plant according to claim 1, characterized in that the Auxiliary transmission paths or auxiliary channels simultaneously for the test of the transmission facilities are used. 10. Plant according to claim 1 and optionally subclaims 2 to 9, characterized in that for controlling rakes works or microcomputers used in the Functions described in whole or in part claims realized by means of a computer program (software) will.