CA2085865A1 - Alarm system - Google Patents

Abstract

ABSTRACT

The present invention provides an improved security alarm system which utilizes a central control panel, alarms, sensors with associated transponders, and arm/disarm means such as a keypad. The system is readily expandable and includes high efficiency step up and step down regulators to permit operating at a higher voltage; the system also includes means of setting the addresses of each transponder without the necessity for the installer to keep track of these addresses.

Description

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The present invention relates to security alarm systems and in particular, relates to improvements in security alarm systems suitable for commercial, residential and industrial use.
The use of security alarm systems is well established in the art and thus such systems range from very basic units primarily used in residential applications, to highly complex systems for relatively large industrial and commercial applications. ~lthough the capabilities of such systems varies to a great degree, the basic elements in all systems remain the same. Thus, a typical system comprises a central control panel, alarm means, sensors and transmitters.
Although the basic elements remain the same the capability of these elements will be variable depending upon the particular requirements. For example, a basic system may include sensor capabili.ties for one or two parameters while larger systems may have multiple sensors - i.e. there may be sensors for theft (glass breakagel forced intrusion, space detection, etc.) fire and smoke sensors, appliance sensors, temperature sensors, etc. Basically, each ~ondition to be monitored utilizes a sensor to de.tect the desired condition or parameter and a transponder is usually associated with the sensor for sending the information sensed to the central control panel~ The sending of the information to the control panel may either be done through hard wiring or through wireless means such as radio transmitters.
Aissociated with the alarm systems are means for arming ~ and disarming the system. In a very basic system, such on/off control may be as basic as means to turn the power on 208~6~

and off while todays more sophisticated systems utilize, to an increasing extent, keypads which are placed at desired entry locations. The keypad can be used to arm or disarm the system as well as to program certain information into the central control panel.
Today, most alarm systems, even in residential applications, have multiple sensors. With the use o~
multip~e sensors, even for a single function such as unauthorized entry, it becomes desirable to be able to identify where the alarm is coming from. ~or example, in a typical residential/commercial/industrial application, an alarm system may use a number of sensors on windows and doors to detect unauthorized entry therein, (this can include both opening and glass breakage) fire and smokP alarms, moisture detection, etc. The sounding of an alarm without indicating the type of problem or area causing the alarm can lead both to considerable problems in trouble shooting any defective sensor and/or quickly identifying the source of the alarm for security purposes. Accordingly, it has now become common practice for alarms to have a number of different zones, each zone heing itself able to support several sensors.
In a residential application, a single zone may, ~or example, include only the bedroom area while another zone would cover general liviny quarters, another zone would cover the basement, etc. This wide range of requirements has lead to the need for most manufacturers to sell a range of alarm systems 7 ths individual category of the system generally being characterized by the number of zones which it can monitor.

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Conventional alarm syskems centralize their processing in the control panel. When utilizing a keypad, the single step of entering a four digit user code at the keypad would entail an exchange on the communication BUS. In this exchanga, the panel queries the keypad, the keypad sends back the first keystroke, the panel will then either acknowledge or not acknowledge this keystroke, and the process is repeated for each of the digits. After entry of, for example, a four digit user code, the central panel will check the codes validity and then take the appropriate action. The central panel would then resume its normal polling of the transponders.
The entry of the four digit user code re~uires a minimum of ten data packets on the BUSo At 1200 baud, this requires approximately 1/lOth of a second. However, if the user wanted to take some other actions such as clock updates, changes, modi~ications to user codes, the panel has to buffer this data until it is complete before anything can be done since the interaction is in serial fashion. In other words~
although the micro controller has the time to do many other things, the keypad entry process is inherently a slow one (being operator controlled) and the micro controller must wait ~or the data to be completed before it can proceed. If there is a second keypad, one must allocate twice the buffers and system resources if th system is to support the second keypad being accessed at the same time. This in turn, - quadruples instead of doubles the ~ommunication BUS traffic since each data packet must contain the address of which ` 208~8~

buffer or keypad it is going to or from. Thus, most manufacturers are not able to offer a large number of split armings without extremely expensive ]price tags.
As can be appreciated, the addition of æone expansion modules to such a BUS could create an unsafe system. Thus, it would be possihle to compromise such a system by keeping the panel busy with keypad input/out]put such that the panel would not be able to discover a system intrusion in a timely fashion.
A further problem with prior art systems is the number of peripherals which can be supported by a typical residential system. Previously, most residential systems consisted of the central panel and a few transponders.
However, recently greater demands have been placed on the systems including a number of additional peripherals. This has led to increased wiring and power loss. In turn, the potential for greater interference on the line exists thus causing more false alarms.
It is an object of the present invention to provide an alarm system which allows for a large number of peripherals.
It is a further object of the present invention to provide an alarm system wherein the address of the transponder may easily be set after installation of the system.
It is an object of the present invention to provide an alarm system which is suitable for use as a basic system and which can easily be expanded to have far greater capabilities. It is also an object of the present invention - to provide an alarm system wherein the control panel cannot be tied up by the keypad for long periods of time.

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The present security alarm system is one which can be used for practically any application ranging from a small residential application to relatively large commercial complexes. The advantage of such a system is the minimization of inventory for the alarm company and the ease of use for an employee installing the systems since they would only need to learn one system type. This would in turn result in fewer faulty installations and fewer false alarms.
For most residential, commercial and industrial applications, a system having between 4 to 32 zones is su~ficient with 4 to 16 zones being one of the most popular system capacities. In the present invention, there is provided a control panel which has a basic six zone capability but which can be expanded to be functional up to 96 zones. The present invention provides zone expansion msdules which can be added on to the basic system as required, either at the time of installation or as a subsequent "add on".
The system pre~erably uses a keypad which is provided with its own micro processor capabilities to minimize the time factors set forth above. Thus, everything that is keypad related such as entry of user codes, bypassing, update, deletion of user codes etc. is done locally at the keyboards. By so doing, when the user, for example enters his four digit user code, the keypad will verify the same and prepares an action code to send to the panel. When the panel queries the keypad, this is sent to the control panel. For ~ example, in the case of arming the system, when the panel queries the keypad, the keypad would send the arm co~mand.

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The panel would either acknowledge or not acknowledge and would arm the corresponding area. The keypad would then set the arm indicator and the panel would continue polling.
Utilizing the above, only three data packets flow on the BUS
for all the keypad functions. No address destination information is required since all data is prepared with no waiting for keystrokes and hence one buffer with associated system resources can accommodate an unlimited number o~
keypads with the only limit being the perceived response time of the system to the user at the keypad. For example, given a rate of ~200 baud at three data packets, this equals 27 milli seconds~ Even given 100 keypads placed on the BUS, the longest wait for a response would be 2.7 secsnds~
Also, most modern alarm systems allow one panel to be shared among several different users. A problem arises when a panel i5 "split" because any keypad can be used to arm/disarm any other split~ This limitation has kept split systems from being used in installations where high security is necessary while the present system allows one panel to protect several different dwellings or offices.
The present invention preferably has both a microprocessor and non-volatile memory on keypads which allows them to function independently of the control panel.
The key pads can verify user codes without having to consult the panel for each key stroke and thus, the same basic panel can be expanded to several splits by simply adding more keypads. Isolating the ~ security codes for each split from each other improves the security thereof.

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It is also desirable that an alarm system have the ability to automatically arm/disarm at a given tlme. In conventional alarm systems, this information was stored in memory on the control panel and thus only one auto arming or disarming time can be provided, common to all users and applicable to all days. The present invention, on the hand, stores the auto arm/disarm times in the keypad and provides them with a medium through which to communicate with the control panel. Thus the system is capable of maintaining several distinct arm/disarm times for each splik and in addition, each time may be individually selected or de-selected for each day of the week.
Conventional alarm panels are responsible for supplying power to their sensors and peripheral devices. As such, most alarm panels and sensors operate from a 12 volt supply.
However, this limits the available supply to sensors and also severely limits the distance which the sensors/transponders can be located from the control panel. While it is possible to use a higher battery voltage, this increases cost by requiring the use of more expensive batteries, larger transformers and non standard sensors.
The present invention uses a high efficiency step-up regulator at the panel which changes the transformer voltage into a higher voltage which is then transmitted to all peripherals such as keypads and transponders. In turn, these peripherals have high efficiency step down regulators to recover th~ lower voltage from which they operate. The kransponder then can supply sensors with the lower voltage.

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The arrangement allows longer wire runs to provide a greater regulation and improves the efficiency of power distribution. ~lso, one obtains betl:er immunity to induced electrical noise such as radio transmissions and inductive motors due to the step down reregulation of the peripheral power supply while still maintaining high power distribution efficiency. The system allows the use of standard peripherals and low cost high resistance wire.
Naturally, alarm systems using transponders require means of communication between the control panel and the remote transponders. This communication takes the ~orm of a voltage or current which is changed between two values, the pattern of these changes representing the information to be transmitted. Because it is desirable to have the largest possible difference between these two voltage levels, most panels maXa use of their supply, or battery as the upp~r level while the lower level is set to ground.
The present invention, by using a high voltage communications BUS through step up regulators to increase the panel supply voltage and thPn using that increased voltage as the upper level for communications, allows communication between panel devices at greater distances. ~lso, noise immunity is improved by providing for a greater signal swing.
Preferably, the system uses a voltage of above 20 volts and conveniently may operate at approximately 28 volts.
In alarm systems, the control panel, in order to talk to one specific device, must assign a unique name or address to - that device so that it can tell when it is being addressed and respond accordingly. A traditional method of assigniny

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these addresses has been by setting a battery of switches on each device to a unigue combination~ Under such a system, the installer must first ensure that no two devices have been given the same combination. This operation is both time consuming and error prone.
In order to overcome the above, a more recent method involves first connecting the devices to the control panel.
The control panel then writes the device's address into a small electronic memory on the device. This avoids having to set switches on the device, but instead requires the installer to perform an extra step and to then keep track of which device is which.
To overcome the above, in a further aspect of this invention, a module allocation system protocol may be utilized. In this method, the installer simply wires up the entire system without regard as to individual device addresses. Once he has finished wiring th~ system, a control panel is made operational and the installer will then go from device to device to ch~ck that each i5 operational. A~ he checks eaeh device, the installer will either press the tamper switch or keys in a special code. This will then cause the control panel to assign a unique and valid address ko that device over the communications BUS. In other words, it is only after the system has been installed that the control panel allocates the individual device addresses.
Having thus generally described the invention, reference will now be made to the accompanying drawings - illustrating an embodiment of the invention in whicho '2~8~

FIGURE 1 is a block schematic representation of an alarm system;
FIGURE 2 is a block diagram showing the system controller and interface therewith;
FIGURE 3 is a block diagram of the keypad and local announciator;
FIGURE 4 is a block diagram showing a typical transponder as utilized in the present invention; and FIGURE 5 is a schematic block diagram of the quick loader.
Referring to the drawings in greater detail, and by reference characters thereto, and in particular referring to Figure 1, there is provided an alarm security system which includes a central system controller 10. Central system controller 10 includes interfaces 10 and 12; interface 12 is a direct interface which is directly wired to sensors 18.
Interface 14 is a communication BUS interface; and example of such an interface is that known as a "pinpoint" TM interface.
Sensors 22, through remote transponders 20, are connected to communication BUS interface 14. A keypad 16 also communicates with the central controller through ~:
communication BUS interface 14. A quick loading means 62 is also provided for reasons which will be discussed in greater detail hereinbelow.
Controller 10 includes a microprocessor 30 which is adapted to monitor sensors 18 and 22. ~hese sensors may include local and/or remote switch contacts at doors and or - windows. Other suitable sensors such as motion detectors, floor mat sensors, fire/smoke detectors, temperature sensors, 208~86~

etc~ may also be utilized.
Interface 14, as previously mentioned, is also capable of monitoring and controlling a plurality of remote transponders 20 via a communications BUS. A number of remote transponders may be coupled either in serial or parallel fashion to the interface with the remote transponders/sensors identifiable either as a particular group or individually.
Central controller 10, in a conventional manner, will respond to detective states of the alarm sensors by producing the appropriate alarm signals which in turn will be sent to suitable alarm devices. The alarm devices may typically include horns, lights, buzzers, etc. In centrally controlled systems, the alarm systems may include a telephone dialer connected to a central switchboard either through a public telephone network or through direct dedicated communication media such as direct wire, radio, etc. It will be understood that the particular response may be partially determined by the system (factory pre-programed) although generally, such responses can be modified by the user and/or installer by suitable programming of the system parameters.

Referring to Figure 2, there is shown a schematic block diagram of the central controller. It will be understood that the various circuits and/or functions descrihed herein are within the capability of those knowledgeable in the art of designing and thus, are not described in greater detail.
The control includes suitable physical mounting means and thus, typically the system will include one or more printed - circuit boards suitably mounted in an enclosure with appropriate coJmection means provided.

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Central controller 10 includes a battery 24 to provide power during any AC power failure so that the ala.m system will remain functional. Low battery cutoff means 26 are provided to reduce system maintenance requirements. If, during an AC power failure, battery 24 should drain below a prsdetermined point (as determined by voltage divider network means 28) the system microprocessor 30 will sense this occurrence and shut off all power to the system except to the microprocessor itself. This arrangement saves the battery 24 from discharge dendrite formation which would otherwise render the battery non rechargeable while, at the same time, providing the minimal power required for micro controller 30 so that it can continue to maintain its real time clock thereby alleviating the system user of the drudgery of having to reset the clock each time following a prolonged power ~ailure~ Also, through the ~eedback provided by the voltage divider network 28, micro controller 30 is able to monitor the charging voltage on battery 24 and can switch, if required, to a fast charge circuit 32. As may be seen from Figure 2, there is also provided power supply means 33 which are connected to AC supply 31.
Power supply means 33 will include a transformer to provide a suitable DC voltage normally in the range of 13 to 18 volts. The output to the battery 24 and low battery cutoff means 26 will be regulated to the desired voltage which is normally approximately 14 volts. The output to the system will also be regulated, but at a substantially higher - voltage - i.e. preferably around 28 volts.

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Alarm output 34 utilizes a MOSFET power transistor 36 instead of a conventional relay. This permits the use of an ex~ernal alarm which can either be a bell, which requires a constant current output, or a siren or other electro mechanical speaker device to which an audio-wave form must be supplied. If desired, an output 35 for an automatic telephone dialer may be provided.
Output connector 38 is provided for all attachable peripherals such as keypads, transponders, etc. and communication is provided by means of a 4 wire BUS. As may be seen from Figure 2, fuse means 40 are provided. A takeoff monitor 42 feeds a sense transistor 44 so that the system microprocessor 30 is able to perform automatic diagnosis to determine if the peripherals are not responding due to lack of power or otherwise.
An internal emulator circuit 46 allows control of the direct wire inputs 48. This permits testing during and/or following manufacturing to provide automatic verification of the circuit correctness and integrity. Thus, for example, if there are any poor solder joints or other faults, these can be tested prior to placing the controller in service. The system, as illustrated in Figure 2, also includes a connection point 50 which may be utilized to supervise the status of the alarm sensors. Connection point 50 can also function as an additional direct wire input through function selection circuit 52.
An AC power loss indicator 54 is provided; associated ~ therewith is a 60 hertz pulse source to drive the counter circuits of the microprocessor 30 for the real time clock.

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Thus, in the event of AC power failure as would be indicated by the loss o~ the 60 hertz pulse train, the system microprocessor 30 has its own crystal frequency source 56 to generate an appropriate clock signal to keep the real time clock operational.
Connection point 50 is provided with serial communication in packet ~raming protocol through drive circuit 58 while there is provided a buffered reset signal 60 active on power up and during BUS retrys.
Quick loader port 63 is provided for easy access to system parameter information held in the system EEPRO~ 64 of microprocessor 30. By utilizing quick loader port 63, the system can be quickly injected with pertinent system information to allow immediate and full operation. Thus, the parameters of a "typical" system can be placed into a suitable quick loading card and then injected into a virgin system through quick loader port 63 so that a lot o~ the lengthy manual programming normally associated with a new system can be avoided. Quick loader port 63 will also provide access for testing purposes during the manufacturing process.
Referring to Figure 3, the circuitry for a typical keypad 16 is illustrated. It will be understood that this circuitry would be assembled on a suitable printed circuit board and housed in a conventional housing which will provide the required mounting and structural integrity. It will be - understQod that although the system only demonstrates one such keypad, a plurality of such keypads may be connected by 20g~6~

means of the 4 wire power, reset and serial packet framing communications BUS interface 68 to the equivalent BUS
connection 50 in the system controller. The communication drive circuit 70 is of the open collector type so that no device can grab and/or hold master control over the BUS
except the circuitry in the system controller location.
Amplification means 72 are provided l:o give local amplification of the reset signal to alleviate signal difficulties that may incur in installations with long BUS
lengths. Input through keypad 75 is by matrix arrangement so that the number of input pins o~ the microprocessor 74 which are required to achieve the input are kept at a minimum.
In a preferable embodiment, the visual displays are multiplexed through a single data latch 76 to two seven segment displays 78A and 78B and to 6 LED's 80 used for status display. To gate the appropriate data signal from data latch 76 to the appropriate display, the LED's se~uentially have power enabled to them through their respective grounding transistors 82 when the appropriate data for them is available on a visual data BUS 84. Audible indications means 86 (local announciator) are provided to~a speaker 88 mounted integral with the keypad's PCB. Keypad identification operating parameters are kept in the micro controllers own dedicated EEPROM 90.
Referring to Figure 4, a typical transponder is illustrated and will now be referred to. As was the case with the keypad, the circuitry of transponder 20 is normally ~ mounted on a suitable printed circuit board and placed in a suitable housing designed to provide the required mounting 208~8~

and structural integrity.
As previously discussed, a plurality of transponders may ba connected by means of the 4 wire power, raset and serial packet communications BUS 104 to equivalent BUS connection point 50 on the system controller. The communication drive circuit 92 is of the open collector type so that no device can grasp and hold master control over the BUS. Local amplification of the reset signal is provided by amplification means 94 to alleviate signal difficulties that incur in installations with long BUS lengths.

Each transponder 20 includes a high efficiency switching regulator means to decrease the voltage to the conventional level of 12 volts. Each transponder also will have its own identification number held in the memory of the local EEPROM 98 of the microprocessor 96.
An internal alarm sensor switch emulator circuit 100 allows control of the direct wire alarm sensor inputs 102 during manufacturing testing to determine if there are any poor joints or other defects during the assembly process as well as allowing a test on the inputs of khe micro controller 96. Provision is made to supervise the status of the alarm sensors through connection point 105 which can also serve as an additional direct wire input by means of ~unction selection circuitry 106.
Port 108 is mechanically compatible with the quick loader port 62 (Figure 2). During installation, the transponder port 108 is connected to port 62 so that the - systems microprocessor 30 can have access to the memory of EEPROM 98 so that the transponders identity numbers can be æos~s~

automatically programed by th0 system microprocessor 30.
Alternatively, the system can be programed such that the systems microprocessor 30 can have direct access to EEPROM 98 by means of the four wire BUS. In either way, this speeds installation time and prevents tampering that would otherwise be a possibility if the ~ransponders identify codes were stored locally in the transponder by means such as d.ip switches.

Thus, the transponder can be provided with a module allocation system protocol. Upon installation of the system, the control panel, once operational, will continually address each device. The installer need only be present at the transponder and either press the tamper switch or key-in a special code which will cause the control panel to assign a unique and valid address to that d~vice over the communications BUS.
Re~erring to Figure 5, a typical quick loader is shown.
As is the case with the other components, the circuitry is con~igurated and assembled on a printed circuit board and housed in a suitable protective material to provide protection against rough handling and the like.
The quick loader may be connected by means of its own connector 110 to provide access to the system microprocessor 30. Power, reset and serial packet framing communications are equivalent to those that exist on the communications BUS connection 38 of the central controller lO. The communication drive circuit 112 is open ~ collector to again prevent any device holding master control over the BUS. Amplification means 114 provide local 2~8~86~

amplification of the reset signal to alleviate signal loading of the device. A local microprocessor 116 has access to the memory of EEPROM 118 so that it can provide the functions of uploading and downloading stored information into the EEPROM 64 of microprocessor 30.
It will be understood that the ,above described embodiments are for purposes of illustration only and that chanyes and modifications may be made thereto without departing from the spirit and scope of the invention.

Claims (5)

1. An alarm security system comprising a central control panel, a plurality of sensors, each sensor being adapted to sense a physical parameter, at least one transponder associated with each of said sensors, said transponders being adapted to transmit information from its associated sensor to said control panel, wire means extending from said transponder to said control panel, DC power supply means associated with said panel and operatively connected to said wire means, high efficiency switching regulator means at said control panel to increase the voltage to a level higher than the voltage of said power supply means, and each of said transponders having a high efficiency switching regulator associated therewith for reducing said voltage.

2. The system of claim 1 wherein said control panel includes a pair of interfaces, a first one of said interfaces being adapted to be connected directly to a plurality of sensors, the second one of said interfaces, being a communications BUS interface, said communications BUS
interface using the higher level voltage from said high efficiency switching regulator at said control panel to thereby improve noise immunity by providing a greater signal swing.

3. The system of claim 1 further including arm/disarm means for activating and deactivating the capability of the control panel to send signals to said alarm means, a plurality of key pads remote from said central control panel, each of said key pads having a non volatile memory capablity and a programmable memory, said programmable memory having sufficient bytes to accept at least one user code.

4. The system of claim 4 wherein each of said key pads has a non volatile memory to store a security code.

5. The system of claim 1 wherein each of said transponders has means associated therewith, such that after installation, means to send a signal to said control panel to then be assigned a unique address over the communications BUS.