火灾报警器毕业论文中英文资料外文翻译文献

1、火灾报警器火灾报警器 中英文资料外文翻译文献中英文资料外文翻译文献 Multiple single-chip microcomputer approach to fire detection and monitoring system A.J. AI-Khalili, MSc, PhD D. AI-Khalili, MSc, PhD M.S. Khassem, MSc Indexing termIndexing term : Hazards, Design, Plant condition monitoring Abstract:Abstract: A complete system for

2、fire detection and alarm monitoring has been proposed for complex plants. The system uses multiple single chip architecture attached to a party line. The control algorithm is based on a two-level hierarchy of decision making, thus the complexity is distributed. A complete circuit diagram is given fo

3、r the local and the central station with requirements for the software structure. The design is kept in general form such that it can be adapted to a multitude of plant configurations. It is particularly shown how new developments in technology, especially CMOS single chip devices, are incorporated

4、in the system design to reduce the complexity of the overall hardware, e.g. by decomposing the system such that lower levels of hierarchy are able to have some autonomy in decision making, and thus a more complex decision is solved in a simple distributed method. 1 Introduction1 Introduction Regulat

5、ory requirements for most high risk plants and buildings mandate the installation of fire detection and warning systems for all sensitive areas of the plant or the building. Most fire codes state the requirement for monitoring and control specifically related to a type of a plant or building such as

6、 chemical plants, petroleum, nuclear plants, residential high-rises etc. A general conclusion of these codes can be specified as the following requirements : (a) The source of all detector signals should be exactly identifiable by the central station (b) An extra path of communication between the ce

7、ntral station and all local controllers (c) Direct means of control of alarm and central equipment by the central station (d) Means of communication between the central station and the fire department (e) Availability of emergency power supply. The codes usually also specify the types and frequency

8、of tests for all equipment. A fire detection and alarm system is a combination of devices designed to signal an alarm in case of a fire. The system may also accomplish fan control, fire door hold or release, elevator recall, emergency lighting control and other emergency functions. These additional

9、functions supplement the basic system which consists of detection and alarm devices and central control unit. Technology has an influence on system architecture. When technology changes, the architecture has to be revised to take advantage of these changes. In recent years, VLSI technology has been

10、advancing at an exponential rate. First NMOS and, in the last year or two, CMOS chips have been produced with the same packing density with more gates per chip yet at a lower power consumption than NMOS. Surely this change in technology must affect our design of hardware at both the chip and the sys

11、tem level. At the chip level, single chips are now being produced which are equivalent to board levels of only the previous year or two. These chips have microprocessor, memory in RAM and ROM, IO Ports both serialand parallel, A/D timer, flags and other functions on chip. At the system level, the ne

12、w chips make new architectures possible. The objective of this paper is to show how technology can influence system architecture in the field of fire control. The new high density single chip microcontrollers are incorporated in the design of a large scale system and yet we obtain a smaller system w

13、ith a better performance. In terms of fire detection and alarm monitoring, this is reflected directly in the local station hardware, because of their remoteness and power supply requirements. A complete local station can be designed around a single CMOS chip with power consumption of a few m W depen

14、ding on system operation. This approach reduces the cost and complexity of design, implementation and maintenance and provides easily expandable and portable design. This implementation was not possible with old technology. Most of fire detection/monitoring systems available are tailored towards a s

15、pecific application and lack the use of recent advances in CMOS VLSI technology. In this study, we develop a fire detection/monitoring system which is general in concept, readily implementable in a multitude of applications for early detection of a fire before it becomes critical, for equipment and

16、evacuation of personnel. Here, we propose a central control and distributed control/detection/monitoring with adequate communication, where use is madeofsingle-chipmicrocontrollersinthelocalstations,thusimproving controllability and observability of the monitoring process. 2 Detection and alarm devi

17、ces A basic fire detection system consists of two parts, detection and annunciation. An automatic detection device, such as a heat, smoke or flame detector, ultraviolet or infrared detectors or flame flicker, is based on detecting the byproduct of a combustion. Smoke detectors, of both ionization an

18、d optical types, are the most commonly used detector devices. When a typical detector of this type enters the alarm state its current consumption increases from the pA to the mA range (say, from a mere 15pA in the dormant mode to 60 mA) in the active mode. Inmany detectors the detector output voltag

19、e is well defined under various operating conditions, such as those given in Table 1. The more sensitive the detector, the more susceptible it is to false alarms. In order to control the detector precisely, either of the following methods isused: a coincidence technique can be built into the detecto

20、r, or a filtering technique such that a logic circuit becomes active only if x alarms are detected within a time period T. The detection technique depends greatly on the location and plant being protected; smoke detectors are used for sleeping areas, infrared or ultraviolet radiation are used when f

21、lammable liquids are being handled, heat detectors are used for fire suppression or extinguishing systems. In general, life and property protection have different approaches. Alarm devices, apart from the usual audible or visible alarms, may incorporate solid state sound reproduction and emergency v

22、oice communication orprinters that record time, date, location and other information required by the standard code of practice for fire protection for complex plants. Heaviside 4 has an excellent review of all types of detectors and extinguisher systems. 2.1 Control philosophy and division of labour

23、 Our control philosophy is implemented hierarchically. Three levels of system hierarchy are implemented, with two levels of decision making. There is no communication between equipment on the same level. Interaction between levels occurs by upwards transfer of information regarding the status of the

24、 subsystems and downwards transfer of commands. This is shown in Fig. 1 where at level 1 is the central station microcomputer and is the ultimate decision maker (when not in manual mode). At level 2 are the local controllers, which reside in the local stations. At level 3 are the actual detectors an

25、d actuators. A manual mode of operation is provided at all levels. Information regarding the status of all detectors is transmitted on a per area basis to the local controllers. Their information is condensed and transmitted upward to the central microcomputer. Transfer of status is always unidirect

26、ional and upwards. Transfer of commands is always unidirectional and downwards, with expansion at the local control level. This approach preserves the strict rules of the hierarchy for exact monitoring detection and alarm systems associated with high risk plants. The classification of the two layers

27、 of controls is based upon layers of decision making, with respect to the facts that (a) When the decision time comes, the making and implementation of a decision cannot be postponed (b) The decisions have uncertainty (c) It will isolate local decisions (e.g. locally we might have an alarm although

28、there may be a fault with the system) 3 General hardware I :Fig. 2 depicts our design in the simplest of forms. The system uses an open party line approach with four conductor cables going in a loop shared by all the remote devices and the control panel. This approach is simple in concept and is eco

29、nomically feasible. However, one major disadvantage is the dependency on a single cable for power and signaling. In cases where reliability is of extreme importance, two or even three cables taking different routes throughout the system may be connected in parallel. Fig. 3 gives the driver circuitry

30、 required to derive an expandable bus. This design takes advantage of recent advances in the single chip microcomputer technology to reduce the interface between the central station and the local stations. 3. 1 Central control task A central unit provides a centralized point to monitor and control t

31、he system activities. In the system to be described the central control unit serves a fivefold purpose. (i) It receives information from the local stations and operates the alarms and other output devices. (ii) It notifies the operator in case of system malfunction. (iii) It provides an overall syst

32、em control manual and automatic. (iu) It provides a system test point of local stations and itself. (u) It provides a central point for observation, learning and adaptation. 3.2 Local stations The local stations can take local decisions regarding recognition of a risk situation, and act independentl

33、y on local affairs. In this technique we depend on load-type coordination, e.g. the lower level units recognize the existence of other decision units on the same level; the central or the top level provides the lower units with a model of the relationship between its action and the response of the s

34、ystem. It is evident that a powerful machine is required at this stage so that all the required functions can be implemented. The availability of the new generation of microchips makes this architecture a feasible solution. A single chip microcomputer was chosen over discrete digital and analogue de

35、vices to interface to the field devices and to the central microcomputer. This is the main reason that previously this approach was not feasible. In selecting the microcomputer for the local stations, the criterion was the requirement for a chip which contains the most integration of the analogue an

36、d digital ports required for the interface and the utilization of CMOS technology owing to remoteness of the local stations. The choice was the Motorola 68HC11A4, for the following reasons: (a) It is CMOS technology; this reduces power consumption. (b) It has a UART on board; this facilitates serial

37、 communication. (e) It has ana/d converter on board; this eliminates an external A/D. (d) It has 4K of ROM, 256 bytes of RAM, 512 bytes of EERROM with 40 1/0 lines and a 16 bit timer; this satisfied all our memory and 1/0 requirements at the local station side. 4 System implementation4 System implem

38、entation The local station: Fig. 3 is the block diagram of the circuit used to utilize the MC68HCllA4 as a remote fire detecting circuit while Fig. 4 illustrates the same circuit in an expanded form. It can be seen that the single microcontroller can be used to monitor more than one detector, thus r

39、educing system cost. The loop power supply, which is usually between 28 and 26 V, is further regulated by a 5 V 100 mA monolithic low power voltage regulator to supply power to the microcontroller. The onboard oscillator, coupled with an external crystal of 2.4576 MHz, supplies the microcontroller w

40、ith its timing signal which is divided internally by four to yield a processor frequency of 614.4 kHz, which is an even multiple of the RS 232 7 baud rategenerator. In this Section the term supervised input or output will be used to mean that the function in question is monitored for open- and short

41、-circuit conditions in addition to its other normal functions. More information can be found in Reference 9. 5 5Main loopMain loop 6 Conclusion This paper describes the development of a large scale fire detection and alarm system using multi-single chip microcomputers. The architecture used is a two

42、-level hierarchy of decision making. This architecture is made possible by the new CMOS microcontrollers which represent a high packing density at a low power consumption yet are powerful in data processing and thus in decision making. Each localstation could make an autonomous decision if the highe

43、r level of hierarchy allows it to do so. It has been tried to keep the system design in general format so it can be adapted to varying situations. A prototype of the described system has been built and tested 10. The control part of the central station is implemented with a development card based on

44、 MC 68000 microprocessor (MEX 68KECB, by Motorola), which has a built-in monitor called Tutor. The application programs were developed using the features provided by this monitor. The local stations controllers were designed using the MC 68705R3, single-chip microcontroller. 7 References 1 Fire prot

45、ection guidelines for nuclear power plants, US NRC Regulatory Guide 1.120 2 BAGCHI, C.N.: A multi-level distributed microprocessor system for a nuclear power plant fire protection systemcontrols, monitoring, and communication, IEEE Trans., 1982 3 PUCILL, P.M.: Fire hazard protection, detection and m

46、onitoring systems, Sea. Con, 2, Proceedings of Symposium on ADV in offshore and terminal measurement and control systems, Brighton, England, March 1979, pp. 353-363 4 HEAVISID, L.: Offshore fire and explosion detection and fixed fire. Offshore Technological Conference, 12th Annual Proceedings, Houst

47、on, Texas, May 1980, pp. 509-522 5CELLENTANI,E.N.,andHUMPHREY,W.Y.:Coordinated detection/communication approach to fire protection, Specify: Eng., 6 Motorola Microprocessors Data Manual (Motorola Semiconductor Products, Austin, Texas, USA) 7 Electronic Industries Association : Interf ace between dat

48、a terminal equipment and data communication equipment employing serial binary data interchange (EIA Standard RS-232, Washington, DC, 1969) 8 MESAROVIC, M.D., MACKO, D., TAKAHARA, Y.: Theory of hierarchical multilevel systems (Academic Press, 1970) 9 KASSEM, M.: Fire alarm systems, MSc. thesis, Dept.

49、 of Elec. 中央或高层提供了一个较 低的单位模型之间的行动和系统响应的关系。很明显，一个强大的机器，需要在 这个阶段，使所有需要的功能得到有效执行。 该芯片的新一代供应使得该体系 结构的解决变得可行。 单片机被选中了离散的数字和模拟设备接口， 到外地设备和中央微机。这是 最主要的原因，以前这种做法是不可行的。该芯片的选择的，包含要求的模拟和 数字接口所需的端口和 CMOS 技术的运用 ， 由于地处偏僻的分控制站最一体 化。 这个选择是摩托罗拉 68HC11A4，理由如下： （1）它是 CMOS 技术，这可减少电力消耗。 （2）它有一个 UART，这有利于串行通信。 （3）它有一个 A

50、/ D转换器上，这消除了外部 A / D转换 （4）它有一个 4K 的 ROM，256 K 内存，512K EERROM 字节 40 个 I/O 端 口的线路和一个 16 位定时器;符合分控制站所有的内存和 1 / 0 的要求。 4 4、系统实施、系统实施 分控制站：图.3 是用于一个远程火灾报警 MC68HCllA4 电路框图 检测电路： 图.4 这是前一个电路的扩展形式。可以看出单片机可用于监控多 个探测器，从而降低了系统成本。 回路电源，通常在26 到 28V 之间，通常五伏一百毫安单片低功耗电压调节 器供电的微控制器。板载振荡器，是一个 2.4576 MHz 的外部晶体结合，提供时 间信号，它被分为 4 个内部收益率为 614.4 千赫，这是一个更多的 RS 232 7 波 特率发生器的处理器频率微控制器。 5 5、主循环、主循环 6 6、结论、结论 本文描述了一个大规模的火灾探测及报警系统， 使用多的发展，单芯片微型 计算机。 该架构是采用两个层次的决策层次。 这种架构是可以用到的新的 CMOS 微控制器，低功耗