APPARATUS FOR THE PREVENTION OF DISASTERS

Abstract: A disaster prevention system has a number of terminal devices (40), such as fire/smoke/gas sensors and relays, connected to a receiver (30) which collects data from them by polling. The system is made in a hierarchy such that a number of protocol converters are the receivers of the lowest rank and come under a main receiver (20), which is connected to an even higher rank system (10). The protocol converters are provided with ROM's which store specific data of the terminal devices. On initial setting of the system, the contents of the ROM's are checked and sent to the main receiver, which stores the data in its own RAM and sends them further to the higher-rank system. Thus, the higher-rank system will automatically have specific data of the terminal device.

Description: [Technical Field] This invention relates to a disaster prevention system such as fire alarm systems, gas leakage alarm systems,anti-theft systems and others, and more particularly to a disaster prevention system arranged so as to be capable of effectively managing and knowing the connection status of terminal units by a higher rank unit. [Background Technics] In disaster prevention systems in which a plurality of terminal units such as fire sensors, repeaters or the like are connected to a receiver for managing and controlling the terminal units, the receiver must know connection information or classifying information as well as status information of the individual terminal units. In particular, in disaster prevention systems in which a plurality of receivers are disposed hierarchically with the terminal units being connected to the lowest-rank receivers, it is necessary that the classification information concerning the terminal units as connected be grasped at the side of the higher-rank receiver. A disaster prevention system in which the classification information of the individual terminal units is transmitted to the receiver together with the supervisory information representative of the operating status of the sensors is disclosed in Japanese Patent Application Laid-Open No.127292/1983. Further, with a view to providing a fire alarm system capable of transmitting the classification information of detectors to a receiver without affecting the signal bit number of detected information, Japanese Patent Application Laid-Open No.65398/1985 teaches a fire alarm system whose operation is based on temporally separated transmissions of the classification information and the detected information, and in which the terminal unit responds to a call requesting the classification information as issued by the receiver by sending back the information of a prescribed level which differs from one to another detector in dependence on the classification of the detectors, to thereby allow the receiver to identify the classification of that detector, wherein the call for the detected information is issued in succession to the termining the classification. The receiver then decides whether a fire has broken out from the detected information as received on the basis of the result of the decision concerning the classification made previously. However, both of -the systems disclosed in -the publications mentioned above suffer from the disadvantage that the transmission rate is low, giving rise to problems in respect to operation efficiency, because the classification information must be transmitted upon every polling. Inherently, the classification information is insusceptible to any dynamic variation, which in turn means that the classification information once transmitted needs not be transmitted again. In the systems disclosed in the abovementioned publications, however, the classification information is transmitted upon every polling. Thus, the systems disclosed in the abovementioned publications are disadvantageous in that the information becomes redundant, resulting in reduction in the transmission rate and hence in remarkable delays even in the transmission of urgent information such as fire information or the like. Moreover, in EP-A-0 004 909 a fire alarm system is described in which fire sensors are delivering a status information such as an alarm or a no-alarm signal to receivers which are disposed hierarchically, and wherein, at an initialization of the system, the connection of the sensors to the receivers is determined by checking if any alarm or no-alarm signal is received, or if no signal at all is transmitted, but no other disaster prevention units are connected and no classification information indicating the type of the unit is transmitted. Therefore, connection of a false unit may not be detected in this system. In EP-A-0 005 842 surveillance of telephone subscribers by polling via telephone lines is described in which collected information is compared, in a central computer, with stored standard information relating to the individual customers including the type of an alarm, but there is no regular polling of classification information from the customers connected to the system. [Disclosure of the Invention] Accordingly, it is an object of the invention to provide a disaster prevention system such as a fire, gas-leakage, or theft prevention system which has an increased transmission rate of status information of terminals units to receivers and in which terminal units the inherent information of which is not in coincidence with a predetermined information are disregarded during the polling operation. For accomplishing the above object, there is provided according to this invention a disaster prevention system including at least one receiver having a plurality of terminal units of certain types connected thereto by at least one transmission trunk, said receiver being adapted to collect an information from said terminal units by polling, and said terminal units being adapted to send an information to a receiver to which they are connected in response to predetermined request calls from the receiver, said information comprising as well an inherent classification information identifying the classification or type of the terminal unit, as a status information indicating the status of the terminal unit at the time of polling the same, wherein said receiver comprises means to collect and to store the requested classification information from terminal units only at the time of an initialization operation of the system, and further means to collect and to determine a status information from those terminal units the previously stored classification information of which coincided with a predetermined information, during the ordinary monitoring operation after initialization of the system, when no more any transfer of inherent classification information is performed. Therein, the classification information sent from the terminal unit to the receiver on request may include, in addition to the type of the terminal unit, an information as to the number, the address, the presence of testing means, or other specific information on the terminal unit, and the terminal units may comprise sensors, specifically those delivering a fire, a gas-leakage, or a theft information, repeaters, smoke prevention or discharge devices, or the like. According to a further improvement, a plurality of receivers are disposed hierarchically, wherein each of the lowest rank receivers has terminal units connected thereto and is arranged as to collect and to store information from said terminal units by polling and to transfer the collected information to the next higher rank receiver, sequentially up to the highest rank receiver. Therein, it is a special advantage to transfer the status information to the higher rank receivers only for such terminal units the collected classification information of which coincided with a predetermined classification information. With the above arrangement, maps of inherent information such as classification information of the terminal units connected to the low rank receivers are transferred sequentially from the hierarchically lowest rank receivers towards the hierarchically highest rank receiver at the first initialization or at an intermediate initialization in the course of operation, whereby inherent information maps are ultimately collected at the hierarchically highest rank receiver automatically, while inherent information concerning the assigned area is also held in the receiver in charge of that area in the course of the collection of the information, as the result of which a procedure for preliminarily setting a map concerning the relevant terminals at each of the associated receivers can be done away with, while the transmission rate can be increased because no transfer of the inherent information is performed during the ordinary monitoring operation of the diaster prevention system. [Brief Description of the Drawings] Fig. 1 is a block diagram showing a general arrangement of a disaster prevention system to which this invention can be applied, Fig. 2 is a circuit block diagram showing an internal circuit configuration of a high-rank system (highest-rank receiver) 10 shown in Fig. 1, Fig. 3 is a circuit block diagram showing an internal circuit configuration of a main receiver 20 shown in Fig. 2, Fig. 4 is a circuit block diagram showing an internal circuit configuration of a protocol conversion unit (lowest rank receiver) 30 shown in Fig. 1, Fig. 5 is a circuit block diagram showing an internal circuit configuration of a terminal unit 40 shown in Fig. 1, Figs. 6A and 6B show flow charts for illustrating the operation of the protocol conversion unit (lowest rank receiver), Figs. 7A and 7B show flow charts for illustrating the operation of the main receiver, Fig. 8 shows a flow chart for illustrating the operation of the host system (highest-rank receiver), and Fig. 9 shows a flow chart for illustrating the operation of the terminal unit. (BEST MODE FOR CARRYING OUT THE INVENTION) In the following, an exemplary embodiment of this invention will be described by reference to the drawings. Fig. 1 shows a general system arrangement of a fire prevention system to which this invention is applied. Referring to the figure, a main receiver 20 is connected to a host system 10 such as a CRT console or the like, while a plurality of protocol conversion units 30 are connected to the main receiver 20, wherein each of the protocol conversion units 30 have a plurality of terminal units 40 such as sensors, repeaters or the like connected thereto. The host system 10, the main receiver 20 and the protocol conversion units 30 each include a respective CPU and they are essentially implemented so as to serve as receivers. Accordingly, in the following description, the host system 10 is also referred to as the highest-rank receiver with the protocol conversion units 30 being referred to as the lowest-rank receivers. Fig. 2 shows an internal circuit arrangement of the host system 10 or the highest-rank receiver including CRT equipment. The highest-rank receiver 10 includes a central processing unit CPU1, a read-only memory ROM11 for storing programs, a random access memory RAM11 to serve as a work memory, a random access memory RAM12 for registration of the terminal instruments and devices, a switch circuit SW11 for setting the (ID) numbers of the low-rank instruments/devices as connected, a display unit DP1, an operating (mainipulating) unit OP1, a sounder unit SP1 and transmission/reception units TR11 to TRln for realizing interconnection with the low-rank instruments/devices, and others. An internal circuit arrangement of the main receiver 20 is shown in Fig.3. The main receiver 20 includes a central processing unit CPU2, a read-only memory ROM21 for storing programs, a random access memory RAM21 serving as the work area, a random access memory RAM22 for registering the terminal units, a switch circuit SW21 for setting presence/absence of interconnection with the higher-rank system, a switch circuit SW22 for setting the (ID) number of the low-rank units as connected, display units DP2, an operating (manipulating) unit OP2, a sounderunit SP2, a printer P2, a transmission/reception unit TR20 for performing communication with the host system 10, transmission/reception units TR21 to TR2n for performing communication with the protocol conversion units 30, and others. Fig. 4 shows an internal circuit arrangement of the protocol conversion unit 30 serving as the lowest-rank receiver. The protocol conversion unit 30 includes a central processing unit CPU3, a read-only memory ROM31 for storing programs, a read-only memory ROM32 for registering addresses and classification (types) of the terminal units, a random access memory RAM31 serving as the work memory, a random access memory RAM32 for registering the terminal units, a display unit DP3, an operating (manipulating) unit OP3, a sounder unit SP3, a printer P3, a transmission/reception unit TR30, a transmission/reception unit TR31 and others. Fig. 5 shows in detail an internal structure of one of the terminal units 40 connected to the lowest-rank receiver, i.e. the protocol conversion unit 30 and can be exemplified by a sensor repeater, smoke prevention/discharge repeater, analogue sensor and the like. Although the internal configuration of the sensor repeater is shown in Fig. 5, it should be understood that other repeaters can also be implemented in a similar structure. The illustrated sensor repeater includes a central processing unit CPU4, a read-only memory ROM41 for storing programs, a classification-setting read-only memory ROM42, a random-access memory RAM41 to serve as the work memory, an address setting switch circuit SW41, a classification setting switch circuit SW42, a transmission/reception unit TR40 for performing communication with the protocol conversion unit 30 and others. Now, description will be directed to the operation of thedisaster prevention system implemented in the structure described above. In precedence thereto, those portions with which this invention is concerned will be briefly described. The read-only memory ROM32 incorporated in the lowest-rank receiver, i.e. the protocol conversion unit 30 is placed with inherent information concerning the addresses and classification or types of the terminal devices connected to this protocol conversion unit 30. At the time of initialization, request for the classification information is issued to each terminal unit or device through first means (blocks 101 to 110 shown in Fig.6A). The classification information sent from each terminal device is compared with the corresponding classification information stored in the read-only memory ROM32. When the comparison results in coincidence, this fact is registered in the terminal registering random access memory RAM32. Subsequently, through second means (blocks 116 to 120 in Fig.6A), the contents registered in the random access memory RAM32 are transferred to the terminal registering random access memory RAM22 incorporated in the main receiver 20. In the main receiver 20, the classification information of the terminal instrument/device as transferred from the protocol conversion unit 30 is registered through second means of the abovementioned main receiver 20 (blocks 201 to 207 and blocks 208 to 211 in Fig. 7A) to the terminal registering random access memory RAM22 constituting a third means, while this registered terminal classification information is further transferred to an even higher receiver constituting the host system 10. In the host system, the terminal classification information as transferred from the main receiver 20 is registered in the terminal registering random access memory RAM12 which constitutes the third means through second means of the host system 10 (blocks 301 to 307 in Fig.8). By virtue of the operation performed at the time of initialization as described above, the classification information inherent to each terminal device which is necessary for the individual receiver to perform ordinary monitoring and control operations can be derived from the contents of registaration in the terminal registering random access memory of each receiver. Figs. 6A and 6B show flow charts for illustrating operation of the protocol convension unit 30 shown in Fig.4. At block 100, operation is started. At block 101, initial values are set. At block 102, address is initialized to zero. Thereafter, polling is started to the terminal units. At the end of the polling to the (n - 1)-th terminal, the value of address is incremented by one (block 103), being followed by the polling to the n-th terminal unit, where an address code added with the classification information request command is sent out onto a transmission trunk line L (block 104) and at the same time a timer is activated (block 105). When the terminal unit allocated with the abovementioned address receives the signal from the protocol conversion unit, that terminal unit sends back the terminal information added with the abovementioned address code, by way of example. In the protocol conversion unit, decision is made as to whether the return signal is received or not from the abovementioned terminal unit within a predetermined time and whether the classification information is issued or not (blocks 106, 107, and 108). When the classification information is not available regardless of whether the return signal is received or not (YES at block 108), it is decided that the terminal unit of concern makes no response, as the result of which the printer P3 prints out that the n-th terminal unit is not present (block 109). Subsequently, unless the final address to be polled is reached (NO at block 110), the address value is incremented by one (block 103), whereupon the similar polling operation takes place at the next address. When the return signal is received together with the classification information within the predetermined time (YES at block 107), the received classification information A of the n-th terminal unit is stored in the random access memory RAM31 serving as the work memory (block 111). Subsequently, the classification information B for the n-th terminal is read out from the terminal registering read-only memory ROM32 (block 112), whereupon the classification information A is compared with the classification information B (block 113). When coincidence is found between A and B (YES at block 113), the classifiction information B of the n-th terminal unit is stored in the terminal registering random access memory RAM32 (block 114). If otherwise (NO at block 113), the non-coincidence of the classification information for the n-th terminal is printed out by the printer P3 (block 115). Subsequently, the similar polling operation is repeated from the succeeding address unless the address value has not reached the final address. Upon completion of the polling for all the terminals units, the terminal registering random access memory RAM32 is in the state of storing the precise classification information, i.e. the inherent information of the terminals currently connected. In this case, according to the illustrative embodiment, the terminal registering random access memory RAM32 is provided with a maximum connectable terminal area in which the address code and the classification information of the terminal for which A = B are stored, while the area for the terminal unit which is not present or for which non-coincidence is found is left blank. It should however be understood that only the (ID) number, the address code and the classification information of the terminal unit for which A = B is valid may be stored in the terminal registering random access memory RAM32 to thereby save capacity in the random access memory. When the inherent information concerning the terminal units actually connected is collected in the terminal registering random access memory RAM32 upon completion of the polling operation for all the terminal units (YES at block 110), an operation takes place for transferring the collected contents to the main receiver 20 serving as the higher rank unit. At first, it is determined at block 116 whether or not a main receiver 20 is present. If not, ordinary monitoring operation is initiated, starting from the block 121 shown in Fig. 6B. The presence or absence of the main receiver may also be established by a switch or the like. In this case, the decision block 116 may also be omitted. When a main receiver 20 is connected (YES at block 116), a message is issued to the main receiver 20 that the classification data is ready to be transferred to the main receiver 20 (block 117), whereupon a relevant interrupt flag is set on the side of the main receiver 20. When the interrupt flag is set at the main receiver 20 in this manner, a transfer request is sent back. Accordingly, it is determined whether the transfer request was sent back or not (block 118). If the transfer request is detected, the stored content of the terminal registering random access memory RAM32 is read out to be subsequently sent to the main receiver 20 (block 119). Subsequently, the transfer request interrupt flag set at the main receiver 20 is cleared, whereby the transfer request message is also cleared (block 120). Now, the protocol conversion unit enters the ordinary monitoring state with the contents of the terminal registering random access memory RAM32, starting from a block 121 shown in Fig. 6B. In Fig. 6B, the operation for monitoring the outbreak of fire is explained, by way of example. Referring to Fig. 6B, the address n is initialized to zero at the block 121, being followed by a block 122 where the address value is incremented by one. Thereafter, the polling for the ordinary monitoring operation is started. Prior to the polling, it is determined by checking the contents of the terminal registering random access memory RAM32 whether the terminal unit of the address to which the polling operation is to be performed is connected or not (block 123). Unless the terminal unit of concern is connected (NO at block 123), the polling operation to that terminal unit is not performed. When the allocated address n is not the final address N for the polling (NO at block 124), the address value is further incremented by one at the block 122, whereupon the polling operation is changed over to the succeeding address. In this manner, unnecessary polling operations are avoided. In the polling operation for the terminal unit of the address n , it is first determined whether a control instruction has issued to the n-th terminal unit by checking the content of the work random access memory RAM31 (block 125). If a control instruction has issued, the address code is added with the control instruction before being sent out (block 126). Unless the control instruction is required (No at block 125), the address code added with status information request command is sent out (block 127). In this connection, the control instruction is, for example, an on/off command or the like to a control circuit or a test circuit of the terminal unit. Upon reception of the signal from the terminal unit (YES at block 128), the received information is stored in the work random access memory RAM31 (block 129), being followed by termining whether it is fire information or not (block 130). If not, the address value is incremented at block 122 by way of block 124, whereupon the next polling cycle is initiated. If the information is fire information, it is determined whether a fire has occured or not. If this shows an outbreak of fire (YES at block 131), the region where the fire is taking place is displayed at the display unit DP3. If there is no fire, the succeeding polling operation is performed. When information of all the terminals units has been collected through the polling operation performed up to the final terminal unit, operation for transferring this information to the main receiver 20 serving as the higher-rank unit is conducted. At first, at block 133, it is determined whether the main receiver 20 is present or not. Thereafter, a message is issued to the main receiver 20 that the transfer of information thereto is ready (block 134), whereupon a transfer-ready flag is set at the main receiver. Upon reception of a return signal indicating that the transfer admission flag is set at the main receiver 20 (YES at block 135), the received information in the work random access memory RAM31 is sent out to the main receiver 20 (block 136). On the basis of the information as received, the main receiver issues a request for transfer of the control instruction to the terminal unit, if necessary. Accordingly, if the transfer request is issued by the main receiver after the information has been sent out to the latter, a transfer request flag is set (YES at block 137). The control instruction to the terminal unit from the main receiver is received to be stored in the work random access memory RAM31 (block 138). This control instruction is sent out to the terminal unit upon next polling operation in the fire monitoring cycle (block 126). After the block 138, the ordinary fire monitoring mode is activated, starting from the block 121. Operation of the main receiver 20 shown in Fig. 3 will be described by reference to flow charts shown in Figs. 7A and 7B. Referring to Fig. 7A, in succession to a start block 200 and an initialization block 201, the (ID) numbers of the low-rank units, i.e. the protocol conversion units 30 connected to the main receiver 20 are read out from the switch circuit SW22 for setting the (ID) numbers of the low-rank units as connected (block 202). In this conjunction, it is to be noted that the presence or absence of connections of the protocol conversion units are previously set in the switch circuit SW22 by an operator or other. After the (ID) numbers of the protocol conversion units 30 as connected have been read out, decisions are sequentially made as to whether the transfer-ready messages has been issued or not by the protocol conversion units of the (ID) numbers as read out (block 203). This decision process can be accomplished by checking sequentially whether the classification information transfer-ready interrupt flags corresponding to the individual protocol conversion units are set or not. If the transfer-ready message has not issued (NO at block 203), it is then decided by way of block 207 whether the similar transfer-ready message to the protocol conversion unit of the succeeding number has issued or not. When the transfer-ready message is detected at the k-th protocol conversion unit (YES at block 203), the transfer request is sent to the k-th protocol conversion unit (block 204). This can be accomplished by first identifying discriminatively the protocol conversion unit which has set the interrupt flag and by setting the classification information transfer interrupt flag for that protocol conversion unit. The classification information of terminal units sent back from the k-th protocol conversion unit in response to the message of the transfer request at the block 204 is stored at a k-th area of the terminal registering random access memory RAM22 (block 205). Subsequently, by clearing the interrupt flag set by the protocol conversion unit for which the transfer or sending-back has been completed, the transfer-ready message from the k-th protocol conversion unit is erased (block 206). Next, the block 203 is regained by way of the block 207 to decide whether the transfer-ready message to the protocol conversion unit of the succeeding number has been performed. When all the classification information has been collected at the protocol conversion units (YES at block 207), procedure proceeds to the transfer to the higher-rank unit, starting from block 208. In this case, decision as to whether or not all the information has been collected is made by comparing the (ID) numbers of the lower-rank units read out at block 202 with the contents stored in the terminal registering random access memory RAM22. At the block 208, it is first decided whether a unit higher in rank than the main receiver 20, i.e. the host system 10 is connected or not. Although this information is previously set at the DIP switch circuit SW21 for discriminating whether or not there is a connection of a host system, the decision mentioned is carried out by checking the contents of the setting. Next, by setting an interrupt flag for the completion of classification information transfer preparations of the host system 10, the host system is informed of the transfer-ready message (block 209). Next, it is decided whether there is a transfer request from the host system by checking whether a classification information transfer request interrupt flag is set or not at the host system (block 210). In response to the transfer request from the host system, if present, the contents stored in the terminal registering random access memory RAM22 are read out to be sent to the host system (block 211). Referring to the flow chart shown in Fig. 7B and beginning with the block 212, description will be made of the ordinary operation of the main receiver performed on the basis of the information concerning connection of the terminal, which information has been transferred from the protocol conversion units and stored in the terminal registering random access memory RAM22. In the first place, decision is made at the block 212 as to whether the terminal information transfer-ready interrupt flag set by the protocol conversion unit is present or not. If present (YES at block 212), the protocol conversion unit which has set that transfer-ready interrupt flag is identified and an interrupt flag indicating the admission of the transfer from the identified protocol conversion unit is set, to thereby allow a transfer admission signal to be sent out to the k-th protocol conversion unit (block 213). Thereafter, the information of the terminals received from the k-th protocol conversion unit is stored in the work random access memory RAM21 (block 214). At block 215, decision is made as to whether or not there is control instruction to the terminal units connected to the k-th protocol conversion unit. If there is, the control instruction is sent out to the k-th protocol conversion unit (block 216), being followed by block 217, which however jumps over from the block 215 when the control instruction is not detected. At the block 217, the transfer-ready signal from the k-th protocol conversion unit is erased, whereupon the sequence for deciding the presence or absence of the transfer-ready signal, starting from the block 212, is regained. When the result of decision at the block 212 is negative (NO), the terminal information stored in the random access memory RAM21 serving as the work memory is subjected to analysis/decision procedure (block 218) by making reference to the classification information stored in the terminal registering random access memory RAM22 through operations indicated at the blocks 203 to 206, whereupon decision is made as to the necessity of display on the basis of the result of the decision/analysis procedure (block 219). In case display is necessary, the result of decision is presented on the display unit (block 220). If otherwise or in succession to the display, decision is then made as to the necessity of control at block 221. If so, the control instruction is stored in the random access memory RAM21 serving as the work memory (block 222), and the transfer request is issued to the relevant protocol conversion unit (block 223). If otherwise or in succession thereto, transfer of information to the higher-rank system, i.e. the host system 10 is activated, starting from a block 224. In the transfer sequence for the host system 10, it is first decided whether there is a higher-rank system (i.e. host system 10) or not (block 224), being followed by the decision as to whether there is a need to the transfer the information to the higher-rank system (block 225). If there is a necessity for the transfer, a flag indicating an information transfer ready-state is set to thereby inform the transfer-ready state to the higher-rank system (block 226). If not or after the transfer, decision is made at a succeeding block 227 as to whether the transfer request has been issued or not. This decision can be realized by detecting if the information transfer request interrupt flag is set at the higher-rank system. When the transfer request is detected (YES at block 227), the terminal information or the result of analysis stored in the random access memory RAM21 is sent out to the higher-rank system (block 228), whereupon the transfer request therefrom is cleared (block 229). If otherwise (NO at block 227) or subsequently, the initial block 212 is regained, whereupon a similar sequence is repeated. Fig. 8 is a flow chart for illustrating operation of the host system 10. In this conjunction, it should be mentioned that operation of the part of the host system with which this invention is concerned is similar to that of the main receiver 20. More specifically, through blocks 300 to 307 shown in Fig. 8, the classification information is collected from the lower-rank unit, i.e. the main receiver 20 in the case of the illustrated embodiment. The operation to this end corresponds to the sequence of operation performed through blocks 200 to 207 shown in Fig. 7A for collecting the classification information from the protocol conversion units by the main receiver 20. Similarly, the processing executed through blocks 308 to 319 shown in Fig. 8 corresponds to the processing executed through the blocks 212 to 223 in the flow chart shown in Fig. 7B for the main receiver. Accordingly, no further description will be necessary. Further, since the host system 10 is the highest-rank unit having no higher-rank unit in the case of the illustrated embodiment, the sequence corresponding to the series of blocks 224 to 229 shown in Fig.7B is omitted from illustration in Fig.8. Fig.9 is a flow chart for illustrating, by way of example, operation of terminal unit shown in Fig.5. After the start at a block 400 and setting of initial values at a block 401, decision is made as to the signal reception (block 402). If the received signal is present, it is then decided whether the received signal coincides with the address of the terminal unit of concern set at the DIP (Dip) switch circuit SW41 (block 403). Upon coincidence, the incoming instruction signal is stored in the random access memory RAM41 serving as the work memory (block 404). Additionally, the status information issued by the receiver circuit or control circuit, i.e. the status information indicating whether the receiver circuit is receiving a fire signal from a fire sensor or whether control circuit is controlling the device under control is fetched to be subsequently stored in the random access memory RAM41 serving as the work memory (block 405). Subsequently, the instruction signal stored in the memory RAM41 is decoded (block 406), to thereby make decision as to whether it is the requests for the classification information (block 407), whether it is the requests for the information obtained from the monitoring (block 408), whether it is a control instruction (block 409) or whether it is a test command (block 410). In case the classification information is required (YES at block 407), the classification information set at the classification setting switch SW42 or the classification information stored in the classification storing read-only memory ROM42 is read out to be sent out (block 411). When the command requests for the information obtained from monitoring (YES at block 408), the status information stored in the random access memory RAM41 serving as the work memory is read out to be sent out (block 412). In the case of the control command (YES at block 409), the control circuit is turned on or off (block 413). Subsequently, the status information is read out from the random access memory RAM41 serving as the work memory to be sent out (block 412). Finally, in the case of the test command (YES at block 410), a test circuit is turned on or off (block 414), being followed by the read-out of the status information from the random access memory RAM41 serving as the work memory to be sent out subsequently (block 412). After the classification information or the status information has been sent out, the block 402 is regained to wait for reception of the next signal. The lowest-rank receiver (protocol conversion unit) may be so arranged as to store therein the inherent information collected from the terminal units connected thereto and at the same time transfer the inherent information to the higher-rank receiver. Further, it may also be so arranged that the inherent information concerning terminal units previously registered in the terminal registering read only memory, such as during manufacture, is transfered to the higher-rank receiver. The inherent information transferred from the lowest-rank receiver to the highest-rank receiver may include in addition to the classification information such information as the (ID) number, the address, the presence or absence of the test circuit and other information specific to the terminal unit. In the case of the embodiment described above, verification as to whether the terminal units are connected correctly or not is performed at the stage of the protocol conversion unit constituting the lowest-rank receiver. It should however be appreciated that the verification may be performed by the higher-rank receiver or system such as the main receiver serving for discriminative decision of occurrence of fire and preparation of associated control instructions, rather than the lowest-rank receivers.

Claims: A disaster prevention system including at least one receiver (10, 20, 30) having a plurality of terminal units (40) of certain types connected thereto by at least one transmission trunk (L), said receiver (30) being adapted to collect information from said terminal units (40) by polling, and said terminal units (40) being adapted to send an information to a receiver (30) to which they are connected in response to predetermined request calls from the receiver (30), said information comprising as well an inherent classification information identifying the classification or type of the terminal unit (40), as a status information indicating the status of the terminal unit (40) at the time of polling the same, wherein said receiver (30) comprises means (RAM32) to collect and to store the requested classification information from terminal units (40) only at the time of an initialization operation of the system, and further means (RAM31) to collect and to determine a status information from those terminal units (40) the previously stored classification information (A) of which coincided with a predetermined information (B), during the ordinary monitoring operation after initialization of the system, when no more any transfer of inherent classification information is performed. A system according to claim 1, wherein the classification information sent from the terminal unit (40) to the receiver (30) on request includes, in addition to the type of the terminal unit, an information as to the number, the address, the presence of testing means, or other specific information on the terminal unit. A system according to claim 1 or 2, in which the terminal units (40) comprise sensors, specificaly those delivering a fire, a gas-leakage, or a theft information, sensor repeaters, smoke prevention or discharge devices, or the like. A system according to one of claims 1 to 3, in which a plurality of receivers (10, 20, 30) are disposed hierarchically, wherein each of the lowest rank receivers (30) has terminal units (40) connected thereto and is arranged as to collect and to store an information from said terminal units by polling and to transfer the collected information to the next higher rank receiver (20), sequentially up to the highest rank receiver (10). A system according to claim 4, in which the lowest rank receivers (30) are disposed to collect, at the time of an initialization of the system, a classification information from the terminal units (40) connected thereto, and to collect a status information from the terminal units during ordinary monitoring operation, and to transfer this status information to the higher rank receivers (20) only for such terminal units the collected classification information of which coincided with a predetermined classification information. A system according to claim 5, in which the receivers are disposed to sequentially transfer the status information of the terminal units (40) to the highest rank receiver (10) where inherent classification information maps of the terminal units (40) connected to the receivers at the time of initialization of the system are collected.

Inventors: IGARASHI AKIRA, KOBAYASHI TAKASHI, IGARASHI, AKIRA, KOBAYASHI, TAKASHI, IGARASHI, AKIRA C/O NOHMI BOSAI KOGYO K.K., KOBAYASHI, TAKASHI C/O NOHMI BOSAI KOGYO K.K.
Applicants: NOHMI BOSAI LTD, NOHMI BOSAI LTD.
Application year: 1988
Main classification: G08B25
IPC codes: H04Q9, G08B25, G08B26