Abstract:
A multi-unit ambient condition detecting system incorporates either a wired or a wireless communication medium wherein the units are in bi-directional communication with one another. Units can incorporate programmed processors and ambient condition sensors such as smoke or gas sensors. In response to detected local ambient conditions, the respective units can transmit messages indicative of the level of sensed ambient condition to other units in the system. The units can maintain running totals of levels of ambient conditions received from other units in the system and combine those received indicators, along with one or more locally generated indicators, to determine that a selected condition, such as fire or gas is present in at least a portion of the region being monitors. Output devices coupled to the communication medium can provide human discernable audible or visible indicators of the presence of one or more selected conditions.

Description:
FIELD OF THE INVENTION 
     The invention pertains to multi-unit monitoring systems. More particularly, the invention pertains to such systems which incorporate multiple programmed processors in bi-directional communication with one another for purposes of improving response time in monitoring selected ambient conditions. 
     BACKGROUND OF THE INVENTION 
     Monitoring and alarm systems are known for purposes of continuously supervising one or more regions with respect to the presence of preselected conditions. For example, intrusion or burglar alarm systems are known for the purposes of monitoring a premises and detecting unauthorized entry therein. Other types of monitoring systems which are known include fire or gas detecting systems, or systems for the monitoring or control of air flow or illumination. 
     It has also been recognized that preferably such systems will have the shortest possible response times so as to signal the existence of the selected condition as quickly as possible without generating false alarms or false positives. Various approaches are known and have been used to address these issues. 
     For example, one approach has been to preprocess signals from ambient condition sensors. An example of such an approach has been disclosed and claimed in Tice U.S. Pat. No. 5,736,928, entitled “Pre-Processor Apparatus and Method” assigned to the assignee hereof. Another known approach contemplates altering degrees of filtering of signals received from ambient condition sensors. One form of this approach has been disclosed and claimed in Tice U.S. patent application Ser. No. 09/120,444, filed Jul. 22, 1998 entitled “System and Method of Adjusting Smoothing”, also assigned to the assignee hereof. 
     While known approaches have been found to be effective and useful in carrying out their purposes, there continues to be need for systems which can benefit from processing signals from multiple units which might be physically near where the ambient condition of interest is originating in the premises. Preferably such systems could provide shorter response times while minimizing false alarms without substantially increasing the manufacturing or installation costs thereof. 
     SUMMARY OF THE INVENTION 
     A multi-unit communication system incorporates a bi-directional communications medium. Examples of representative media include cable, either optical or electrical, or a wireless medium. 
     Units can include programmed processors coupled in bi-directional communication with the medium. Units can send and receive messages from other units via the medium. At least some of the units incorporate condition monitoring circuitry. 
     The receiving units can combine condition related information or messages received from other units. In this regard, for example, a selected receiving unit might include circuitry for storage of condition related information received from other units. 
     The receiving units also include circuitry for analyzing the received information, perhaps in combination with locally generated information from a condition sensor coupled to the receiving unit. The analysis can result in a determination that a preselected condition is indicated by the combined information. 
     In one aspect, the units can be implemented as programmed processors. In such an embodiment, stored executable instructions in combination with processor circuitry implement the bi-directional communication function as well as the analysis function. 
     In yet another aspect, a receiving unit can incorporate one or more thresholds, which might be adjustable, for purposes of determining if the combined condition-related information exhibits selected predetermined characteristics. In one embodiment, the units can transmit as condition-related information, indicia of the presence of a selected condition such as smoke or gas. The transmitted indicia can be combined at a receiving unit, along with a locally generated indicium indicating ambient smoke or gas to form a composite indication of the degree thereof in a preselected group of units or in a subregion being monitored. 
     In yet another aspect, output devices can be coupled to the medium. The output devices, which might incorporate programmed processors, include circuitry for producing human discernable indicators of the presence of predetermined conditions such as fire or gas. The indicators can be visual or audible. The output devices respond to and energize their respective output indicating elements based on messages received from one or more combining units via the medium. 
     Units, in yet another aspect of the invention can be grouped. Condition related information from the members of a selected group can be processed to establish a group determination as to presence of one or more preselected ambient conditions such as fire or gas. 
     A variety of processes can be used to establish the presence of the selected condition. For example, the results of the combination of received condition information at a selected receiving unit can be compared to one or more thresholds. Alternately, a unit which exhibits the greatest indicator based on combining received condition information can notify other units in the system of the presence of an alarm condition. Pattern recognition and/or fuzzy logic processing can also be used. 
     In yet another alternate, a control element can be coupled to the communication link. In addition to the processors communicating with one another, they can in turn communicate with the control element. The control element can in turn make a determination as to the existence of a preselected ambient condition. 
     Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a multi-unit communication system in accordance with the presence invention; 
     FIG. 2 is a block diagram of a representative unit usable in the system of FIG. 1; 
     FIG. 3 is a flow diagram illustrating selected processing aspects implementable in the system of FIG. 1; and 
     FIG. 4 is a block diagram illustrating in more detail the processing step of FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     While this invention is susceptible of embodiment in many different forms, there are shown in the drawing and will be described herein in detail specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated. 
     FIG. 1 illustrates a system  10  in accordance with the present invention. The system  10  includes a plurality of electrical units  12   a,    12   b  . . .  12   n.  At least some of the units are in bi-directional communication with other units via a communications medium indicated generally at  14 . It will be understood that the nature of the medium is not a limitation of the present invention. The medium can be implemented using electrical or optical cables. Alternately, the ambient atmosphere can be used as a wireless medium. 
     At least some of the electrical units, such as  12   a,    12   c,    12   n  include local ambient condition sensors indicated as  16   a,    16   c  and  16   n.  These ambient condition sensors can sense a variety of ambient conditions without limitation including motion, position, temperature, fire, gas or the like. 
     Those electrical units which include ambient condition sensors transmit local condition related, sensor generated information via medium  14  to other units in the system  10 . Receiving units store, at least temporarily, condition related information received from other electrical units indicated generally at  18   a,    18   b,    18   c  . . .  18   n.  Information can be stored in binary storage units or in any other form of storage without departing from the spirit and scope of the present invention. 
     At least some of the units, such as  12   a,    12   b,    12   d  include circuitry for processing the stored ambient condition information. The stored ambient condition information can also be combined with locally generated ambient condition information from local sensors such as  16   a,    16   c  . . .  16   n.    
     The various electrical units also include circuitry which, in response to the combining process, determines if a selected criterion has been met. For example, and without limitation, the combined ambient condition information can be compared to an amplitude or a velocity threshold. Alternately, the combined information can be processed using pattern recognition or fuzzy logic processing to establish that the stored information, with or without locally generated ambient condition information corresponds to a predetermined criterion. The selected criterion could, for example, indicate the presence of a fire condition, a gas condition or an intrusion without limitation. 
     More specifically, information  18   a  received from other units could be added together with condition information received from sensor  16   a  and compared to a predetermined threshold value. Alternately, all of the information  18   a  could be input along with information from sensor  16   a  to a pattern recognition process to determine if a predetermined fire or gas profile is present. 
     One or more electrical units which has established that a predetermined criterion has been met can transmit messages, via medium  14 , to, for example, an output device  20  also coupled to the medium  14 . The device  20  could, for example, be a visual-type output device such as a blinking indicator or a strobe or an audible output device such as a loudspeaker, a horn, a siren or the like, without limitation. In response to a received message or messages, via medium  14 , the output unit  20  could in turn energize one or more output devices, providing a human perceptible indication of the presence of a predetermined condition. 
     If desired, a common control element  22 , coupled to medium  14 , can be provided to transmit instructions or commands and to receive data from the electrical units  12   a,    12   b  . . .  12   n.  The form of the common control unit  22 , which could be implemented as one or more programmed processors, is not a limitation of the present invention. 
     It will be understood that the electrical units  12   a,    12   b  . . .  12   n  in accordance herewith are capable of receiving messages from other electrical units in the system in connection with sensed ambient conditions, processing one or more of the received messages, along with perhaps locally generated ambient condition information. A respective unit can make a determination that the processed information is indicative of the presence of a predetermined condition. 
     It will also be understood that various of the electrical units such as  12   a,    12   b  and  12   c  could be grouped and carry out processing relative to messages received only from group members. In this regard, unit  12   c,  upon receipt of appropriate messages from units  12   a,    12   b  could carry out group related processing of that information to determine if the group information exhibits a predetermined criterion or profile. 
     Electrical units such as unit  12   c  can be members of one or more groups without limitation. Hence, a given electrical unit, such as  12   c,  could carry out group related processing relative to units  12   a,    12   b  and  12   c  as well as group related processing of units  12   c,    12   d . . .    12   n  without limitation. It will also be understood that the common control element  22 , if present, could be used to establish groups of electrical units  12   a . . .    12   n.    
     FIG. 2 is a block diagram of a selected electrical unit  12   i.  Unit  12   i  includes a programmable processor  30   a  which can execute prestored instructions  30   b.  Coupled to processor  30   a  is input/output circuit circuitry  30   c.  Where for example, the medium  14  was implemented as some form of a bi-directional communications cable, circuitry  30   c  would include appropriate interface circuits for coupling signals to and receiving signals from the cable. In the event that the medium  14  was wireless circuitry  30   c  would include an appropriate wireless transmitter and receiver or transceiver. 
     Coupled to processor  30   a  is an ambient condition sensor  16   i.  The executable instructions  30   b  are stored in one or more storage units indicated generally at  32 . The unit or units  32  could be implemented with a variety of circuitry including read/write circuitry or read only memory or programmable read only memory without departing from the spirit and scope of the present invention. 
     A portion of the unit  32  includes storage circuitry wherein one or more sets of received ambient condition information  18   i - 1 , - 2  . . . -n received via medium  14  can be stored. Each of the sets of stored information, such as  18   i - 2 , could represent ambient condition information associated with a group which includes processor  30   a.  Hence, as illustrated, processor  30   a  could be included in each of groups I, II, . . . n. 
     Control instructions  30   b  in addition to implementing communications with other units, via medium  14 , also process received ambient condition information, stored at least temporarily in unit  32 . The processing carried out by instructions  30   b  is to determine if selected sets of ambient condition information, which might include information from sensor  16   i,  correspond to a predetermined criterion as discussed above. 
     For example, and without limitation, if the sensors  16   a,    16   c,    16   i . . .    16   n  were smoke sensors and units  12   a,    12   c,    12   i  and  12   n  were in the same group, respective ambient condition information might be stored in a portion of storage unit  32  indicated generally at  18   i - 2 . That information could in turn be processed by instructions  30   b  by comparing some processed form of that information to a predetermined amplitude or velocity threshold to establish the presence of a fire condition. Alternately, the information could be coupled to pattern recognition processing instructions or fuzzy logic-type processing instructions. Such processing could be used to determine if a fire profile had been detected. 
     In the event that the unit  12   i  determines the presence of a selected condition, input/output circuitry  30   c  can be used to transmit via medium  14  a condition indicating message to output unit  20 . Output unit  20  can in turn energize one or more audible or visible output devices so as to provide a human discernable indication of the presence of the selected condition. It will be understood that unit  20  could incorporate a processor driven by executable instructions in combination with a strobe unit or audible alarm unit. 
     FIG. 3 is a flow diagram illustrating exemplary processing  100  of the system  10 . In a step  102 , groups can be defined if desired. If no groups are defined, then the entire plurality of units can be treated as being in a common group. 
     In a step  104 , group related ambient condition information from group members is collected at one or more selected group members. For example, all members of the group can collect transmitted ambient condition information from other group members. 
     In a step  106 , the collected ambient condition information is processed at the respective member or members with or without that group member&#39;s locally generated ambient condition information. 
     In a step  108 , the selected group members determine if a selected profile indicative of fire, gas, intrusion or the like has been recognized. If so, in a step  110 , one or more output devices can be activated. In a step  112 , an alarm message can be transmitted to the other units and to the common control unit if present. 
     FIG. 4 is a block diagram of a process  120 , which discloses further details of processing step  106  in FIG.  6 . At a selected detector, for example detector  1 , ambient condition information is received, step  122 , from detector n. 
     The received information is in a form which corresponds to a processed value of the output signal from the ambient condition sensor of detector n. That signal might have been processed to remove noise and other transients. It could have been compared to a pre-established threshold to produce a signal indicative of a percent of a value of interest. One type of threshold is an alarm threshold where detector n would normally be expected to be signalling the presence of an alarm condition. Another type is a pre-alarm threshold. Where detector n is a fire detector, the percent of alarm signal is an indication of how close the parameter being measured, such as smoke, heat, gas, and light is to indicating the existence of a fire. 
     It will also be understood that the receiving detector, such as detector  1 , or other receiving electrical unit could determine the percent of alarm if it has a record of the sensitivity of the transmitting detector. It will be understood that the exact form of the information received at detector  1  is not a limitation of the present invention. 
     In a step  124  at the receiving detector, the address of the transmitting detector is compared with addresses previously stored in a table. The table includes, for example, those members of a group with which detector  1  is associated. The signals associated with the addresses in the table are to be combined together, such as by being summed, or by taking differences or ratios to evaluate rates of change either over time relative to a selected transmitting detector or at the same time between different detectors. 
     In a step  126 , if the address of detector n has already been entered into the table, the current percentage of alarm value is used to update the value in the table. In a step  128 , the values in the table can be processed by summing the updated percentage of alarm values for the detectors in the table. In a step  130 , the result of the summing process of step  128  can be compared to one or more preselected values. The preselected values can correspond to predetermined prealarm or alarm conditions. 
     In step  130 , for example, percentage of alarm signals from three detectors indicative of 30%, 60%, and 20% have been summed producing a value in excess of 100% which corresponds to an alarm state which could be entered in step  132 . In the event that the sum from step  128  falls below the predetermined threshold or thresholds, processing continues in step  134 . 
     If in the step  126 , the percentage of alarm signal received from detector n corresponds to clear air or zero, the entry can then be removed from the table in a step  136 . If in the step  124  a determination is made that the address of detector n is not in the table, it can be entered, if appropriate, in a step  138 . For example, detector n can be newly assigned to the group associated with the detector  1 . In such instance, it would be appropriate to enter the address of detector n into the table in step  138 . 
     Examples 1 through 3 are indicative of processing at detector  1  as illustrated in FIG. 4 for different detector addresses and for different percentage of alarm conditions received at detector l. “% A 1 ” corresponds to signals received from detectors where the respective detector compares a sensor output signal to a selected threshold, for example a pre-alarm or an alarm threshold. 
     It will be understood that the exact form of processing carried out at detector  1  based on the received values is not a limitation of the present invention. For example, processing could include summing as discussed previously as well as other processing including forming averages, filtering the received signals or evaluating rate of change of information without limitation. Where respective detectors transmit a percent of alarm (% A 1 ) signal, such signals are sensitivity independent. Outputs from different types of detectors or detectors having different sensitivities can be directly combined and processed when expressed in a % A 1  format. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
               
               
                 EXAMPLE 1 = 30% received from detector #10 
               
             
          
           
               
                   
                 Old Table 
                   
                 New Table 
                   
               
             
          
           
               
                   
                 Address 
                 % Al 
                 Address 
                 % Al 
               
               
                   
                   
               
               
                   
                  8 
                 20 
                  8 
                 20 
               
               
                   
                 10 
                 20 
                 10 
                 30 
               
               
                   
                 14 
                 30 
                 14 
                 30 
               
               
                   
                 Sum = 
                 70 
                 Sum = 
                 80% 
               
               
                   
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
               
               
                 EXAMPLE 2 = 30% received from detector #18 
               
             
          
           
               
                   
                 Old Table 
                   
                 New Table 
                   
               
             
          
           
               
                   
                 Address 
                 % Al 
                 Address 
                 % Al 
               
               
                   
                   
               
               
                   
                  8 
                 20 
                  8 
                 20 
               
               
                   
                 10 
                 20 
                 10 
                 20 
               
               
                   
                 14 
                 30 
                 14 
                 30 
               
               
                   
                 Sum = 
                 70 
                 Sum = 
                 100% 
               
               
                   
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
               
               
                 EXAMPLE 3 = 0% received from detector #8 
               
             
          
           
               
                   
                 Old Table 
                   
                 New Table 
                   
               
             
          
           
               
                   
                 Address 
                 % Al 
                 Address 
                 % Al 
               
               
                   
                   
               
               
                   
                  8 
                 20 
                 — 
                 — 
               
               
                   
                 10 
                 20 
                 10 
                 20 
               
               
                   
                 14 
                 30 
                 14 
                 30 
               
               
                   
                 Sum = 
                 70 
                 Sum = 
                 50% 
               
               
                   
                   
               
             
          
         
       
     
     From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.