Fire alarm system and method for operating the same

Abstract: In a fire alarm system or the like, a plurality of terminals (T₁₁-T₄₄) such as fire detectors or repeaters are connected in plural groups (G1-G4) to a central receiver unit. During system polling of the groups individually those groups respond to the receiver unit which have a status change in any of its terminals. By subsequent point polling of the terminals individually only in that group which had responded during system polling, a responded terminlal is determined very quickly and reliably. Thus, information is collected and processed selectively from the terminal which responded during the point polling.

Description: Technical Field The invention concerns a fire alarm system in which plural terminals such as fire detectors and/or repeaters are connected to a receiver unit, wherein the terminals are devided into plural groups, and which is equipped with a polling means to perform polling of the terminals and to respond to the receiver unit at a return timing of a terminal having a status change and to access other terminals in that group to which the terminal which has reponded belongs, and a method for operating the same. Prior Art US-A-4 525 700 discloses a fire alarm system having a main unit, in which a plurality of sensor terminals are divided into a pluralty of groups. When during a polling of the terminals a sensor transmits a fire signal, the main unit accesses the other terminals of the same group and indicates a fire if another sensor of the same group has also transmitted a fire signal. Therby erroneous fire alarm signals are eliminated. In this fire alarm system, during polling, all individual terminals or groups are called up successively from the receiver unit and information on its status is called up from each of the terminals. In these prior art systems, the polling time from a call of a predetermined terminal till receipt of data indicating the status of the terminal by the receiver unit is fixed, and shortening of the polling time has its limits. Therefore, in such fire alarm systems, it is not possible to quickly transmit predetermined information from terminals such as fire detectors and/or repeaters to a receiver unit such as a control panel or a repeater, and in many cases the time needed for a receiver unit to grasp the status of all terminals connected to the receiver unit is not as short as needed. But, since there is a limit to shortening of the polling time in conventional prior art systems, it is difficult to comply with the request to further shorten the time needed for the receiver unit to surely grasp the status of all terminals in which an abnormality has occured among those connected to the receiver unit. In US-A-4 586 040 a time division multiplex remote control system is described in which a plurality of terminals, divided into a plurality of groups, are connected to a central controller. Also in this system, the central controller transmits a transmission signal to each of the terminals and receives reply signals from the individual terminals during a standing-by period. Therfore, a considerable polling time is needed. Summary of the Invention The object of the present invention is to provide a fire alarm system which is capable to further shortening the time needed for the receiver unit to surely grasp the status of all terminals in which an abnormality has occured among those terminals connected to the receiver unit. The invention by which this object is achieved is characterized in that the polling means comprises: a) system polling means to perform polling of the groups individually and to respond to the receiver unit at the return timing of a group, b) point polling means to perform point polling of the terminals individually only in the group which responded to the receiver unit at the return timing of the terminal having a status change, and c) selecting means to perform selecting and/or processing of information from the terminal responded during the point polling. This fire alarm system according to the invention is built in such a way that plural terminals such as fire detectors and supervisory repeaters connected with the fire detectors or control repeaters connected with apparatus being controlled such as local bells or the like are divided into plural groups and connected to the receiver unit in a special and specific way, i.e. the terminals are supervised by performing a system polling on each terminal group individually. If there is a group which responded to the receiver unit at the time of system polling, the terminals in this group are called by point polling in order to see which of the terminals in this group responds, specifically. If there is a terminal which responded at the time of point polling, the responded terminal is called by selecting means in order to collect information from said terminal. Further, the present invention allows to quickly control one or more terminals associated with the terminal which detected an abnormality, and/or one or more specific terminals in the fire alarm system. Further, the present invention allows to make provisions which enable a common command to be transmitted simultaneously to plural terminals in the fire alarm system. Further, the present invention permits periodically supervising the signal lines in the fire alarm system for line interruption. Still further, the present invention increases the reliability of signal transmission by polling in the fire alarm system. The present invention requires that polling be performed only on each terminal in those group(s) in which at least one terminal showed a change in its status, and there is no need of performing polling on terminals in any other group which has no terminal showing a status change. Therfore, it is possible to considerably shorten the time needed for the receiver unit to surely and reliably grasp the status of all terminals which show an abnormality among a plurality of terminals connected to the receiver unit. Brief description of the drawings Preferred embodiments of the invention are described in conjunction with the accompanying figures. Fig. 1 shows an example of a fire alarm system with terminals divided into groups. Fig. 2 shows an example of the mode of operation of this fire alarm system. Fig. 3 shows a block diagram of an example of the control panel RE as receiver unit in the above system, and an example of connection between the control panel RE and the repeater. Fig.4 is a block diagram which shows an example of the repeater T1 as terminal in the above embodiment and an example of the detectors or the like connected to the repeater T1. Fig. 5 is a drawing which shows a system flowchart of the control panel RE in the above embodiment. Fig. 6 is a flowchart which shows the system polling S2 of Fig. 5 in more detail. Fig. 7 is a flowchart which shows the operation of point polling S4 in Fig. 5 in more detail. Fig. 8 is a flowchart which shows a practical example of selecting S6 in the above embodiment in more detail. Fig. 9 is a flowchart which shows the operation of selecting S9 for line interruption supervision in the above embodiment in more detail. Fig. 10 is a flowchart showing an example of operation other than the flowchart shown in Fig. 3 and operational interruption when the operating unit OP is inputted. Fig. 11 shows a main flowchart of the repeater in the above embodiment. Fig. 12 is a flowchart which shows a practical example of the system processing U3 in Fig. 11 in more detail. Fig. 13 is a flowchart which shows a practical example of the point processing U5 in Fig. 5 in more detail. Fig. 14 is a flowchart showing a practical example of the selecting processing U7 in Fig. 11 in more detail. In the figures the following references are used: RE Control panel T1 - TN Terminals G1 - G4 Groups of terminals DE Fire detector SPAD Code showing system polling GAD Group address SAD Terminal address CM1 Status information return command CM2 Specific information return command CM3 Sounding command (control command) CM4 Fire resetting command (common command) CL Kind information (classification) RAM11 - 23 Random access memories ROM11 - 27 Read-only memories IF11 - 27 Interfaces Description of preferred embodiments Fig. 1 shows an example of the terminals divided into groups in an embodiment of the invention. In this example, terminals T11 - T44 are divided into four groups G1, G2, G3, and G4 and are connected to a control panal RE as an example of a receiver unit. Although four terminals are shown in one group in the embodiment, the number of the terminals may not necessarily be limited to four, and can be any other number. The terminals may also be divided into any other number of groups other than four. Each of the terminals T11 - T44 is a fire detector (analog type or ordinary type) or a repeater. To this repeater, supervisory apparatus (fire detector and the like) or apparatus to be controlled (local bell, fire door, smoke damper and the like) are connected. The control panel RE performs polling on the terminals T11 - T44 in the modes of system polling, point polling and selecting, collects predetermined information from one or more predetermined terminals and controls the predetermined terminal(s). System polling is a form of polling which is performed on each of the four terminal groups formed by dividing the terminals T11 - T44, but not on each one of these terminals, separately. It gives return timing to each group being polled so that a group which has a terminal or terminals showing a change in its status can respond to the control panel RE at return timing. Point polling is a form of polling which is performed only on each of the terminals in a group which responded to the control panel RE during the system polling. It gives return timing to each terminal so that a terminal or terminals which have a change in its status can respond to the control panal RE at return timing. Selecting is performed to collect predetermined information from the terminal responded to the control panel RE during the point polling and to transmit a predetermined control command to said terminal or to one or more optional terminals. At the time of the system polling the control panel transmits a common command or commands to the plural terminals simultaneously. The common commands include, for example, a fire resetting command (a command for resetting the terminal(s) which initiated a fire signal such as detector and repeater, and/or terminals which caused the local bell to sound, to their normal supervisory state), a resetting command for delayed action (a command for resetting the terminal(s) which initiated a fire signal such as fire detector or repeater to perform the delayed action for discriminating whether the fire condition is continuing for a predetermined length of time), and a local alarm silencing command (a command for silencing the local bell). Furthermore, the control panel successively calls the plural terminals with a request for specific information. When the specific information is received from said terminal, the control panel judges that there is no line interruption between the control panel and said terminal. The control panel also uses the "kinds of terminals" information (hereinafter called "kind" information) received from the terminals as the specific information mentioned above and compares it with the "kind" information previously registered in the control panel. If the both "kind" information should not match , the control panel judges that said terminal has been changed with a different kind of terminal. Fig. 2 shows an example of operation, which proceeds in the upper line from the left end toward the right end, then on the line immediately below from the left end to the right end, and so on. Fig. 2 also shows operations of the control panel RE and the terminal (or group) above and below the horizontal line, respectively. Also in Fig. 2, the frame drawn with broken lines indicates that there was no response at the return timing while the one drawn with bold lines indicates that there was a response at the return timing. In other words, the bold line frame indicates a terminal having a change in its status (or a group which has a terminal having a change in its status) as compared with the status at the time immediately before the return timing. Firstly, system polling is performed at P1 in Fig. 2. After transmitting the address SPAD showing the system polling and the status information return command CM1 to the groups G1 - G4, the control panel RE successively gives the groups G1 - G4 timing for their returning status information. Each of the groups G1 - G4 responds to the control panel RE by returning status information at its return timing only if there is a change in status of any of the terminals in the group. In the case of the example shown in Fig. 2, the terminal T23 has a change in its status, and accordingly the group G2 alone responds to the control panal RE. Thus, the control panel RE is able to know that one of the terminals T21 - T24 in the group G2 has a change in its status and possesses status information to be transmitted to the control panel RE. Next, point polling is performed at P2. The control panel RE transmits the address GAD of the group to be polled and the status information return command CM1 to the terminals in the group. In the case of the above example, the control panel RE transmits the address GAD (2) and the status information return command CM1 to the terminals T21 - T24, successively giving these terminals timing for their returning status information. Each of the terminals responds to the control panel RE by returning status information at its own timing only if there is a change in its status. Since the terminal T23 has a change in its status at the above point polling, this particular terminal T23 alone responds to the control panel RE. Thus, the control panel RE is able to know that the terminal T23 has a change in its status and possesses status information to be transmitted to the control panel RE. Then, selecting is performed at P3. The control panel RE transmits the status information return command CM1 and the address SAD of the terminal from which the response signal has been received. Since the response signal has been received from the terminal T23 in the case of the above example, the control panel RE transmits the address SAD (23) of said terminal and the status information return command CM1. In response to this, the terminal T23 transmits its self-address SAD (23) and the data DA which the terminal desires to transmit (for example a fire signal) to the control panel RE. On receipt of the data DA, the control panel RE returns the self-address SAD (23) and the received data DA to the terminal T23. Then, the terminal T23 compares the returned data DA with the data DA which was transmitted immediately before. If both data match, the terminal T23 transmits the above data to the control panel RE again. When the first and the second data DA received by the control panel RE match, the control panel RE recognizes the data DA as the one that has been transmitted from the terminal T23 and performs necessary processing on the basis of the received data DA. In the event that a "fire" decision has been made as a result of discrimination of the data DA which the control panel RE received by the above selecting, the "n"-th apparatus to be controlled is operated (for example, the local bell is sounded) at P4. In the above example, the control panel RE transmits the address SAD(n) of the terminal Tn and the sounding command CM3. As the terminal Tn is called by the control panel RE and receives the local bell sounding command CM3, said terminal Tn returns its self-address "n" and the sounding command CM3 received to the control panel RE for confirmation. As the terminal Tn is called by the control panel RE and receives the same sounding command CM3 from the control panel RE again, said terminal Tn controls the local bell to sound for the first time and returns the data DA on control status and the self-address SAD (n) to the control panel RE. After this, the operation returns to the normal conditions and the above system polling is repeated. Now, processing of the common command is described hereinafter. As the operator inputs the fire resetting command which is one of the common commands in the control panel RE at P6 in Fig. 2, the control panel RE transmits the address SPAD showing the system polling and the fire resetting command CM4. Accordingly the supervisory terminal resets to the supervisory state, and the control terminal discontinues the control (for example, the local bell stops sounding), and the fire alarm system returns to the normal supervisory state. While in the above example the common command such as the fire resetting command is transmitted only once, its transmission may be repeated plural times (e.g. five times) so that the common command may be executed as a right one when the same common command has been received more than a predetermined frequency (for example, more than three times), thus preventing false operation due to transmission error. In the above example, the point polling and the selecting are performed twice respectively for the purpose of preventing false transmission due to induction noise. The operation to check for "open" in the main transmission line L is described hereinafter. At P01 in Fig. 2, the system polling is performed once, and then the selecting is performed to check for open in the main transmission line L extending to the terminal T11. Describing this in more detail, the control panel RE transmits the address SAD (11) of the terminal T11 and the specific information return command CM2, and the terminal T11 returns the self-address SAD (11) and the specific information (in this case the "kind" information CL indicating the kind of the terminal) to the control panel RE. On receipt of the "kind" information CL from the terminal T11, the control panel RE judges that there is no open in the main transmission line L extending from the control panel RE to the terminal T11. Then, the system polling is performed once to confirm that there exists no terminal having a status change, and after this the same line interruption check is performed with respect to the terminal T12 in the same manner as described before. In this way, the line interruption check is performed with respect to the transmission line from the control panel RE to each terminal, and the system polling is performed once immediately. If any of the groups responded during this system polling, the point polling and the necessary selecting are of course performed with respect to this particular group. The "kind" information CL includes the ones showing the supervisory repeater, control repeater, supervisory and control repeater, analog type fire detector and the like. By collecting the "kind" information as the above specific information by the control panel, it is possible to know on the part of the control panel whether or not a terminal or terminals have been connected, and at the same time whether any change has been made regarding the kinds of terminals. Since the selecting for the line interruption check is performed each time the system polling is performed in the above example, it is necessary to repeat the system polling sixteen times for supervision of all the terminals T11 - T44. The line interruption check may be performed each time the system polling has been performed at a predetermined frequency or at an interval of predetermined time, and further the selecting for line interruption check may be performed on plural terminals at a time. It is possible to prevent misjudgement due to induction noise by successively performing the selecting for line interruption check on the same terminal twice. The specific information may be ones other than the "kind" information, for example, specific codes. Fig 3 is a block diagram showing examples of the control panel RE in the above embodiment and of the connection between the control Panel RE and the repeaters. The control panel RE is equipped with a microprocessor MPU1, RAM11 - RAM19, ROM11 - ROM13, IF11 - IF13, a signal transmission/receiving unit TRX1, an operating unit OP and a display unit DP. The ROM11 is an area where programs related to the flowcharts shown in Fig. 5 - 10 are stored. The ROM12 is a storage area for terminal map tables such as the number n of the repeaters T1 - Tn, the group g to which the repeaters belong, the number m within the group and kinds. The ROM13 is a storage area for interlocked control tables. The RAM11 is a working area. The RAM12 is a storage area for the group number g which transmitted a response signal at the time of system polling. The RAM13 is a storage area for the terminal number n which transmitted a response signal at the time of point polling. The RAM13 may be made to store the group number g and the terminal number m within the group instead of the terminal number n which transmitted the response signal, and to judge the terminal number n on the basis of group number g and terminal number m. The RAM14 is a storage area where the controls effected at the time of system polling are stored. The RAM15 is an area where the terminal numbers to be controlled and controls effected at the time of selecting are stored. The RAM16 is a storage area for status information collected from from the terminals T1 - Tn. The RAM17 is a storage area for the control command codes which have been transmitted. The RAM18 is a storage area for the kinds of the connected terminals. The numbers and kinds of the terminals stored in the ROM12 are loaded at the time of initial setting, but are changed thereafter according to the "kind" information collected through the line interruption check. The RAM19 is a storage area for the terminals connected with a line or lines which have been judged as being in interrupted state as a result of the line supervision for "open". The signal transmission/receiving unit TRX1 comprises a parallel/series converter, a signal transmission circuit and a series/parallel converter. The operating unit OP is equipped with various switches and ten keys. The display unit DP is equipped with various indicator lamps and a CRT. Fig. 4 is a block diagram showing a practical example of the repeater T1 in the above embodiment in more detail and examples of detectors and the like connected to the repeater T1. The repeaters T2 - TN have the same composition as the repeater T1. The repeater T1 is equipped with a microprocessor MPU2, RAM2 - RAM23, ROM21, ROM22, IF21 - IF27, a signal transmission/receiving unit TRX2, a fire signal receiving circuit FSR, a line interruption supervisory circuit ELS, a test circuit TE, a local alarm control circuit LAC, and a terminal response circuit ERR. The ROM21 is a storage area for programs related to the flowcharts shown in Fig. 11 - 14. The ROM22 is a storage area for the group addresses to which the terminals belong, the self-addresses and kinds of the terminals. A dip switch may be used in lieu of ROM22. The RAM21 is a working area. The RAM22 is a storage area for status information. The RAM23 is a storage area for the changed status information. The signal/receiving unit TRX2 is the same as the signal transmission/receiving unit TRX1. The fire signal receiving circuit FSR comprises a zone relay or a comparator which detects a fire signal from the fire detector DE. In the case of the above embodiment a self-holding circuit is to be provided. The line interruption supervisory circuit ELS is a circuit for detecting an open in the zone lines L1, L2 and initiating a line interruption signal upon detection of an open. The test circuit TE transmits the fire signal to the fire signal receiving circuit FSR when conducting the test. The local alarm control circuit LAC is a circuit which controls sounding of the local bell B. The terminal control circuit ERC is a circuit which controls the devices ER such as fire doors, smoke vent dampers, and a fire extinguishing system. The terminal response circuit ERR is a circuit which receives response signals from the controlled devices. The main transmission lines L (shown in Fig. 3) are, for example, a pair of power supply/signal lines extending from the control panel RE to the repeaters T1 - Tn as terminals. The zone lines L1, L2 are a pair of power/supply lines. The fire detectors DE are connected to the zone lines L1, L2 which are running from detector to detector without interruption. The fire detector is of an ordinary ON - OFF type which initiates a fire signal on detection of a fire phenomenon exceeding a predetermined level. The end line device ELD is an end of line resistor provided at the end of the zone lines L1, L2. While in Fig. 4 the repeater T1 is specified as being a combined type which is used both for supervision of abnormality detectors such as fire detectors and for the control of local alarm devices and various controlled devices, separate types of repeaters, i.e. one for supervision and the other for control, may be provided. In case a gas sensor is connected as abnormality detector, for example, a gas leak signal receiving circuit is provided in lieu of the fire signal receiving circuit FSR. In case the terminal itself is an abnormality detectors, e.g. an analog type fire detector, a fire phenomenon detecting means having fire a fire phenomenon detecting unit, an amplifier circuit, a sample hold circuit, and an AD converter is connected to the IF22, and the line interruption detecting circuit ELS, the local alarm control circuit LAC, the terminal control circuit ERC, and the terminal response circuit ERR are omitted. The operation of the above embodiment is described hereinafter. Fig. 5 is a system flowchart of the control panel RE in the above embodiment. Firstly, the initial setting is made (S0) in order to see whether there is a control interruption (S1). This control interruption is an interruption which occurs with input from the operating unit OP, or is caused by selecting during the supervision. If there is no control interruption, the system polling is performed (S2). If a status change is found during this system polling (namely, if there is a group which transmitted a response signal) (S3), the point polling is performed (S4). If a status change is found during this point polling (namely, if there is a terminal which transmitted a response signal (S5), the selecting is performed (S6). If no status change is seen when the system polling is performed the selecting for line interruption check is performed (operation to check and see whether the terminals T11 - T44 are properly connected to the control panel RE without interruption) (S7) on each of the terminals T11 - T44 in the event that there is no responded group when the system polling is performed. If there is a control interruption at S1, but no command (commands such as fire resetting command, resetting command for delayed action and local alarm silencing command which are common to the plural terminals and discriminated by memories in the RAM14) (S8), the selecting is performed (S9) to effect individual controls according to the memories in the RAM15. If there is a common command at S8, the system polling is performed (S2) to effect control by the common command stored in the RAM14. Fig. 6 is a flowchart which shows the system polling S2 in Fig. 5, in more detail. Firstly, the control panel RE transmits the address SPAD which shows the system polling and the status information return command CM1 (S12) and sets the terminal group number g to 0 (S13) because normally control interruption operation by common command is not required (S11). And, if there is a response signal (S15) when the predetermined time corresponding to the return timing of the group G1 has passed (S14), the group number g which initiated the response signal is stored in the RAM12 (S16). Then the terminal group number is incremented by one (S18), and the above operations S14 - S16 and S18 are repeated until the terminal group number g reaches the last terminal group number g (S17), and the operation returnes to the main program. On the other hand, if there is an input command (control interruption command) from the operating unit OP, the command code is read out (S19) from the RAM14 where the control interruption information is stored, and the SPAD and the command code are transmitted (S20). If the command code transmitted then is the fire resetting command (S21), the memories in the RAM 14 and RAM15 are not needed and therefore erased (S22), the control interruption flag is off (S23), and the operation returns to the main program. In the event that the command code is not the fire resetting command the corresponding command in the RAM14 is erased (S24) to prevent it from being retransmitted, and the control interruption is off and the operation returns to the main program if no information for terminal control has been stored in the RAM15. If there is a memory in the RAM15 (S25), the control interruption is not off and the operation returns to the main program. Fig. 7 is a flowchart which shows the practical operation of the point polling S4 in Fig. 5, in more detail. Firstly, it checks to see if there is a group or groups which include a supervisory terminal such as a repeater connected with fire detectors in the groups in which the terminal having the status change stored in the RAM12 are included. If there exists a group which includes the supervisory terminal (S31), said group number g is read out from the RAM12 (S33), and the frequency k of the point polling is set to one (S34). Then, the address of said group and the status information return command CM1 are transmitted, and the terminal number m of said group is set to 1 (S35, S36). When the response signal has been received from the terminal m whithin the predetermined time (S37, S38), judgement is made as to whether the response has been received during the first or the second polling (S41). If during the first polling, the receipt of the response signal from the terminal number m is stored in the RAM11 (S42), and the above operation is repeated up to the last number of the terminals in the group (S39, S40). Then, the frequency k of the point polling is changed to 2 (S46, S47), and the address of the group and the status information return command CM1 are transmitted again (S35). Now, when it is the second point polling (S41), the judgement S43 is made as to whether the response signal has been received from the terminal m both in the first and in the second polling (S43). If so, the terminal number n corresponding to the terminal number m is stored in the RAM13 (S45) and the latter number m in the RAM11 is erased (S44). When the above operations have been repeated up to the last terminal in the group, the group number g in the RAM12 is erased (S48), and the operation returns to the main program. If there is no group which includes the supervisory terminal at the step S31, the first group number g to be point polled is read out from the RAM12 (S32). Although it is described above that the point polling is to be performed twice, the frequency of the point polling may be determined to be once or three or more times. If there is no need of giving priority to point polling on the group in which the supervisory terminal is included, the point polling may be performed on the groups in the order as stored in The RAM12. In this case, S31 and S33 in Fig. 7 are omitted. Fig. 8 is a flowchart which shows a practical example of the selecting S6 in the above embodiment, in more detail. In the supervisory mode (S51) of this selecting, the terminal number n is read out from the RAM13, and the address of the terminal number n and the first status information command CM1 are transmitted to the terminals (S52, S53), then a predetermined length of time is given to await a signal indicating the received information (address and data from repeater as terminal), hereinafter called "received signal" (S54, S55). If the signal is received (S54), the received data is stored in the RAM11 to compare it with secondarily received data, and the address of the terminal number n and the received data DA are transmitted to the terminal number n (S56, S57). Then a predetermined length of time is given to await the "received signal" (S58, S59). If the signal is received and the first received data and the secondarily received one are the same, the received data are stored in the RAM16 (S60, S61). At this time the data in the RAM11 and the terminal number n in the RAM13 are erased (S62, S63), and data in the RAM16, if any have been stored, are processed and necessary indications are given (S64, S65), i.e. indications of fire and/or status information are given on the basis of the data stored in the RAM16. From results of processing of the received data in the RAM16, judgement is passed as to whether the delayed action is required for confirmation of fire (S66). If it is required, the resetting command code for delayed action is stored in the RAM14 to prepare for start of delayed action, and the control interruption is set (S67, S68), then the operation returns to the main program. If the resetting for delayed action is not required, but the interlocked control is required at S66, the terminal number and the command code are stored in the RAM15 and the control interruption is set, referring to the interlocked control table ROM13 (S69, S70, S68). On the other hand, in the case of interruption operation (in the control mode) at the selecting S6, the terminal number n and the command code are read out from the RAM15, and the address of the terminal number n and the command code CM3 are transmitted for the first time (S71, S72). And a predetermined length of time is given to await a "received signal" (Address and data from the repeater). If the signal is received (S73,S74), the received data DA are stored in the RAM11, and the address of the terminal number n and the command code CM3 are retransmitted for the second time (S75, S76). Then, a predetermined length of time is given to await and receive a "received signal" (S77, S78). When the control command and the secondarily received information on the control status of the terminal have matched (S79), the command code and the terminal number n transmitted already are stored in the RAM17 to judge later on whether the command sent and the resultant control match or not, and said terminal number n and code are erased from the RAM15 to prevent them from being retransmitted (S79a, S79b). Fig. 9 is a flowchart showing the practical operation of the selecting for line interruption supervision in the above embodiment, in more detail. Firstly, the address b of the repeater which performs line interruption supervision is incremented by one, and the transmission frequency k is set to 1 (S81, S82). While the transmission frequency k is set to twice in the above embodiment, it may be set to three or more times in order to confirm that the transmission has been made without fail. The frequency of transmission may also be determined to be once, only. Then, the address of the terminal number b and the specific information return command CM2 are transmitted (S83), and a predetermined length of time is given to await a "received signal" (S84, S85). Since the transmission has been made only once at this time of the receipt of the "received signal" (S86), the received "kind" information CL is stored in the RAM11, and the transmission frequency k is renewed to 2 (S81, S88). Then, the operation returns to S83, and the address of the terminal b and the specific information return command CM2 are retransmitted. Upon receipt of the "received signal", the second transmission has been completed (S84 - S86), and therefore the first "kind" information is compared with the second one (S89). When these two "kind" information have matched, the "kind" information of the terminal b is read out from the RAM18 (S90). When the information of the terminal b has matched the former one (S91), the operation returns to the main program. If they do not match, it means that the terminal b has been changed to a different kind terminal by mischief or due to construction work. therefore, the "kind" information of the terminal b stored in the RAM18 is changed to the newly received one, and this change is displayed and/or printed (S94, S95). On the other hand, in the event that the first and the second "kind" information do not match at S89, the abnormality of the terminal b connection is stored in the RAM19 and displayed and/or printed (S96, S97). If the address b of the repeater for which line interruption supervision is performed has matched the last address N in the course of these operations, the address b is set to 0, and the operation returns to the main program. Fig. 10 is a flowchart which shows the operation other than that shown in Fig. 3, and a practical example of the operation interruption when the operating unit OP is input, in more detail. Firstly, an input information is read in from the operation unit OP (S101). If it is a fire resetting command (S102), the fire resetting command code is prepared and stored in the RAM 14, and then the control interruption is set by flag or the like (S103 - S105). If the input information is not for fire resetting but resetting for start of delayed action, the resetting command code for start of delayed action is prepared (S106, S107). If it is the local alarm silencing command, the corresponding local alarm silencing command code is prepared (S108, S109). If it is the test command, the test command code is prepared and stored in the RAM15 together with the terminal number n (S110 - S112). If it is the terminal command command, the control code is prepared and stored in the RAM15 together with the terminal number n (S113, S114, S112). As typical example of the test command at S110, the fire test command may be mentioned, in which case a simulated fire is produced or a gas leak test is conducted. The terminal controls are effected, for example, by ON/OFF control command and include switch-on of the fire door, and switch-off of the smoke vent damper, fire extinguishing device or the like. Fig. 11 is a main flowchart of the repeater in the above embodiment. The repeater has a terminal number as well as a group number. Firstly, the initial setting is performed, and if there is a "signal" indicating the system polling, the system processing is performed (U0 - U3). If it is not the system polling signal, the point polling is performed when it has matched the group number in which the repeater is included (U4, U5). If it does not match the group number but the terminal number itself, the selecting processing is performed (U6, U7). Fig. 12 is a flowchart showing a practical example of the system processing U3 in Fig. 11, in more detail. Firstly, when the status information return command CM1 is received, the group number g is set to 0, and the status information is read through the fire signal receiving circuit FSR, the zone line interruption supervisory circuit ELS and the terminal response signal receiving circuit ERR (U11 - U13). Then, it is compared with the preceding status information stored in the RAM22 to see if there is any status change. If there is a change, the status information with the change is stored in the RAM23 to renew the status information in the RAM22 (U14 - U16). And if there is a memory in the RAM23, a response signal is transmitted when the group number g and its own group number Gk match after lapse of a predetermined time. Then the operation returns to the main program (U17 - U21). In case the group number g and its own group number Gk do not match, the group number g is incremented by one (U20). On the other hand, if the command received at the time of system processing is not the status information return command CM1 but the fire resetting command, the FSR, ELS, LAC, ERC and ERR are reset, the RAM21 - RAM23 are set to their initial state, and the operation returns to the main program (U22 - U24). If it is the resetting command for start of delayed action, the fSR is reset. If it is the local alarm silencing command, the LAC is controlled and silenced (U25 - U28). Fig. 13 is a flowchart showing a practical example of the point processing U5 in Fig. 11, in more detail. When performing the point processing, the terminal number m in the group is set to 0. If there is a memory in the RAM23, the response signal is transmitted when the terminal number m and its own terminal number Mk in the group have matched after the lapse of a predetermined time (U31 - U36). In case the terminal numbers m and Mk do not match, the terminal number is increased by one (U35). Fig. 14 is a flowchart showing a practical example of the selecting processing U7 in Fig. 11, in more detail. Firstly, if the command specified by selecting is the status information return command CM1, a status information is read from the RAM23, and the self-address and the status information (data DA) are transmitted (U41 - U43). If there is a "received signal" corresponding to the self-address, the status information is read from the RAM23 (U44 - U46). If the status information and the received data have matched, the self-address and the status information are retransmitted, and the status information in the RAM23 is erased for the first time (U47 - U49). If there is no "received signal", ore the "received signal" even if received, does not match the self-address, a predetermined time is given for standby mode (U50). After the step U49, said command in the RAM21 is erased, and the operation returns to the main program. In the event that no status information return command has been received at the step U41, the frequency k of the selecting processing performed is set to 1. When the specific information return command CM2 is received, a "kind" information is read from the ROM22, and the self-address and the "kind" information CL are transmitted (U51 - U54). Then, the frequency k of the selecting processing performed is incremented by one, and if the "received signal" corresponds to the self-address (U56 - U58), the operation returns to U52. On the other hand, when a control command is received instead of then specific information return command at U52 and the selecting processing is performed once, the self-address and the received control command CM3 are transmitted, and then, the received control command is stored in the RAM21 (U59 - U62). In the case that the control command is received and the selecting processing is performed twice (U60), the contents of the command is set in said circuit when the control commands received during the first and the second selecting have matched, a control status is read-in from said circuit, and the self-address and the read-in control status information (data DA) are transmitted to erase said command in the RAM21 (U63 - U67). Then the operation returns to the main program. At U57, a predetermined period of time is given to await a second signal (U68). If no second signal is received, said command in the RAM21 is erased (U67), and the operation returns to the main program. Despite the foregoing, the point polling and selecting may be performed only once respectively in the above embodiment. When performing the selecting in the above embodiment, the predetermined information (data DA in the case of the above embodiment) which the control panel RE has collected from the terminal responded during the point polling (terminal T23 in the case of the above embodiment) is returned to the terminal T23. If this returned information is the same as the data DA, the terminal T23 retransmits the data DA to the control panel RE. The control panel judges whether or not the retransmitted information is the same as the returned data DA. This means that the ordinary selecting is performed twice in the above-mentioned case. By performing the selecting twice as described above, it is possible to confirm respectively on the part of the control panel RE and of the terminal that the status information received from the terminal is a right one and that the status information sent has properly been received at the control panel RE, thus preventing transmission of such false information as might be caused by induction noise. In the above case, the control panel collects predetermined information from the terminal responded in the course of point polling and returns the information to the said terminal. When the returned information is the same as the predetermined information, said terminal retransmits the predetermined information to the control panel. The control panel is equipped with a selecting means to judge whether or not the retransmitted information is the same as the returned information. Also, in the above embodiment, the point polling may be performed twice on the predetermined terminal group. Speaking more precisely, the polling is performed twice on each of those terminals in the group which responded to the control panel RE at the time of point polling. When the same terminal has consecutively received the response signal twice, this termininal is determined to be one that transmitted the response signal, and selecting is performed on this particular terminal. By doing this, it is possible to prevent transmission of such false information as might be caused by induction noise during the point polling. In this case, later selecting may be performed twice as described above. Also in the above embodiment the point polling may be performed three or more times on each of the predetermined terminals. It is well understood that the expression "fire alarm" or "fire detector", in the sense of the invention, shall include detecting and signalling all kinds of phenomena caused by fire or any combustion process as well as other dangerous abnormalities such as toxic or harmful gases or excessive temperatures or the like.

Claims: A fire alarm system in which plural terminals (T11 - T44) such as fire detectors and/or repeaters are connected to a receiver unit (RE) wherein the terminals (T11 - T44) are divided into plural groups (G1 - G4), and which is equipped with a polling means (P1) to perform polling of the terminals and to respond to the receiver unit (RE) at a return timing of a terminal (T23) having a status change and to access other terminals in that group (G2) to which the terminal (T23) which has responded belongs, characterized in that the polling means (P1, P2, P3) comprises: a) system polling means (P1) to perform polling of the groups (G1 - G4) individually and to respond to the receiver unit (RE) at the return timing of a group (G2) having a status change in any of its terminals (T23), b) point polling means (P2) to perform point polling of the terminals (T21 - T24) individually only in the group (G2) which responded to the receiver unit (RE) at the return timing of the terminal (T23) having a status change, and c) selecting means (P3) to perform selecting and/or processing of information from the terminal (T23) responding during the point polling. A fire alarm system according to claim 1, characterized in that the selecting means (P3) comprises means to perform selecting for collection of a predetermined information from the terminal (T23) responding during the point polling (P2). A fire alarm system according to claim 1 and/or 2, characterized in that the selecting means (P3) comprises means to perform selecting for transmission of a predetermined control command to a terminal related to the terminal (T23) responding during the point polling (P2) or to a specific terminal. A fire alarm system according to any of the preceding claims, characterized in that the system polling means (P1) is designed in such a way that the receiver unit (RE) transmits a common command to the plural terminals (T11 - T44) at the time of system polling. A fire alarm system according to claim 4, characterized in that the common command is at least one of the group of a fire resetting command, a resetting command for delayed action, or a local alarm silencing command. A fire alarm system according to any of the preceding claims, characterized in that the point polling means (P2) is a means to repeat point polling plural times on each of the terminals (T21 - T24) in the group (G2) which responded to the receiver unit at the time of system polling (P1) and to judge, when the response signal has been received from the same terminal predetermined times , that this terminal is the one which has transmitted the said response signal. A fire alarm system according to any of the preceding claims, characterized in that the selecting means (P3) is provided with a line interruption supervisory means which gives a decision that there is no open circuit in the line (L) between the receiver unit (RE) and the terminal which responded with specific information when the receiver unit called the plural terminals successively requesting specific information. A fire alarm system according to claim 7, characterized in that the line interruption supervisory means of the selecting means (P3) is designed to call up one or plural terminals successively and to request transmission of the specific information each time when system polling (P1) is repeated a predetermined number of times. A fire alarm system according to claim 7 or 8, characterized in that the specific information is an information on the kinds of the terminals, and the line interruption supervisory means is designed to check the "kind" information received from said terminal with regard to the "kind" information registered in the receiver unit (RE) and to judge whether said terminal has been changed to a different kind of terminal. A fire alarm system according to any one of claims 1 - 7, characterized in that the selecting means (P3) is designed to repeatedly select the same terminal several times. A fire alarm system according any one of claims 1 - 7, wherein the selecting means (P3) is a means which enables the receiver unit (RE) to collect predetermined information from the terminal which responded in the course of the point polling (P2), to return the predetermined information collected to said terminal, which retransmits the information to the receiver unit when the returned information is the same as the predetermined information, and to judge whether or not the retransmitted information is the same as the returned information. A method for operating the fire alarm system according to one of the preceding claims 1 - 11, wherein plural groups of terminals are connected to a receiver unit, characterized by the steps that a system polling (P1) is performed on the groups of terminals individually, a response is received in the receiving unit at the return timing of a group having a status change in any of the terminals of this group, a point polling (P2) is performed on the terminals individually only in the group which responded to the receiver unit at the return timing of the terminal having a status change, and a selecting (P3) is performed to select and/or process information from the terminal responded during the point polling.

Inventors: SHUTOKU RYUJI C O NOHMI BOSAI, TAKAHASHI KAORU C O NOHMI BOSA, TSUMUJI AKIO C O NOHMI BOSAI L, SHUTOKU, RYUJI, C/O NOHMI BOSAI LTD., TAKAHASHI, KAORU, C/O NOHMI BOSAI LTD., TSUMUJI, AKIO, C/O NOHMI BOSAI LTD.
Applicants: NOHMI BOSAI LTD, NOHMI BOSAI LTD.
Application year: 1990
Main classification: G08B26
IPC codes: G08B26, H04Q9, G08B17