火灾报警器中英文文献翻译

外文文献原稿和译文

原 稿

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 term : Hazards, Design, Plant condition monitoring

Abstract: A complete system for 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 for 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 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 Introduction

Regulatory 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

火灾报警器中英文文献翻译

the building. Most fire codes state the requirement for monitoring and control specifically related to a type of a plant or building such as 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 central 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 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 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 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 system 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 serial and parallel, A/D timer, flags and other functions on chip. At the system level, the new 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

火灾报警器中英文文献翻译

obtain a smaller system with 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 depending 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 specific 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 evacuation of personnel. Here, we propose a central control and distributed control/detection/monitoring with adequate communication, where use is made of single-chip microcontrollers in the local stations, thus improving controllability and observability of the monitoring process.

2 Detection and alarm devices

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 and 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 voltage 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

火灾报警器中英文文献翻译

alarms. In order to control the detector precisely, either of the following methods is used: a coincidence technique can be built into the detector, 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 flammable 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 voice communication or printers 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

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 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 and 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 unidirectional 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.

火灾报警器中英文文献翻译

The classification of the two layers 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 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 economically 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

火灾报警器中英文文献翻译

routes throughout the system may be connected in parallel. Fig. 3 gives the driver circuitry 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.

火灾报警器中英文文献翻译

3. 1 Central control task

A central unit provides a centralized point to monitor and control the

system

火灾报警器中英文文献翻译

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 system 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 independently 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 system.

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 devices 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 and 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 communication.

(e) It has an a/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.

火灾报警器中英文文献翻译

4 System implementation

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 reducing 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 with 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 rate generator. 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-circuit conditions in addition to its other normal functions. More information can be found in Reference 9.

5

Main loop

火灾报警器中英文文献翻译

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-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 local station could make an autonomous decision if the higher 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 MC 68000 microprocessor (MEX 68KECB, by Motorola), which has a

built-in

火灾报警器中英文文献翻译

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 protection 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 system controls, monitoring, and communication’, IEEE Trans., 1982

3 PUCILL, P.M.: ‘Fire hazard protection, detection and monitoring 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, Houston, Texas, May 1980, pp. 509-522

5 CELLENTANI, E.N., and HUMPHREY, 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 : ‘Interface between data 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. of Elec. & Comp. Eng., Concordia University, Montreal, Canada, 1985

10 LIE, P., and KOTAMARTI, U.: ‘The design of a fire alarm system using microprocessors’, C481 Project, Dept. of Elec. and Comp. Eng., Concordia University, Montreal, Canada, 1986

火灾报警器中英文文献翻译

译 文

基于单片机的火灾探测和监控系统

A.J. AI-Khalili, MSc, PhD

D. AI-Khalili, MSc, PhD

M.S. Khassem, MSc

关键词：危险，设计，设备状态监测

摘要：火灾探测及报警监控已成为一个复杂而完整的体系。该系统采用多个单芯片架构到一条主线上。该控制算法是基于两级决策层次，因此分配了复杂性。一个完整的电路原理图，给出了主、分控制器所需的软件的结构要求。设计延续一般形式，这样可以适应于多种系统的配置。尤其显示出新的技术发展，特别是CMOS单芯片器件，在系统设计中的使用，以减少整体硬件的复杂性，例如，通过分解系统，这样的层次较低水平的控制器能够有一些决策自主权，用简单的分布式的方法解决了复杂的决策。

1、引言

大多数高风险地区和建筑物的管理要求安装火灾探测报警系统。多数国家消防规范的要求监测和控制具体的是危险场合或建筑物，如化工厂，石油类，核电厂，住宅高楼等这些场合的一般性质可以指定为下列要求 ：

（一） 所有探测器信号源信号能被主处理器准确识别。

（二）主从控制器有另外的沟通路径。

（三）检测报警和主控制设备由控制中心控制。

（四）火灾现场和控制中心的通讯。

（五）提供的应急电源。

它也被用来应对特殊情况和进行深被检测。

火灾探测及报警系统是一个旨在信号 ， 在一旦发生火警报警装置的组合。 该系统也可实现风扇控制，防火门关闭或释放，电梯锁定，应急照明控制和其他

火灾报警器中英文文献翻译

紧急任务。这些额外的功能补充由检测和报警装置和中央控制单元组成。

技术对系统结构有很深的影响。 当技术的变革，该架构必须修订，以利用这些新的功能变化。近年来，超大规模集成电路技术已经大大进步。第一，NMOS在过去的一年或两年，CMOS芯片以相同的堆积密度拥有更多的门和更低的功耗。 当然这种技术的变化必然影响在芯片和系统级我们的硬件设计。在芯片级，单芯片现在正在制作的是只相当于上一年或两年的水平。这些芯片有微处理器，RAM和ROM，IO端口存储器串行和并行，A / D转换定时器，和其他功能的芯片。在系统级，新的芯片做出新的结构成为可能。本文的目的是体现技术如何影响消防控制领域的系统结构。新的高密度的单芯片微控制器纳入一个大系统的设计，但我们可以得到了更好的性能，更小的系统。在火灾探测和报警监控系统中，这是直接反映在分控制站的硬件，因为地处偏远和电源的要求。一个完整的分控制站可以围绕着一个带电源的CMOS芯片设计。这种方法降低了成本和设计复杂性，方便实施和维护，并提供易于扩展和便携式设计。这是旧技术不可能实现的。大部分火灾检测/监测系统提供特定的应用程序，缺乏对CMOS超大规模集成电路技术的应用。在这项研究中，我们开发了火灾检测/监测系统，常规设计，易于执行的早期发现火警。在这里，我们提出一个中央控制和分发控制/检测/充分的沟通，如果使用的单芯片微控制器在分控制站，从而提高可控性和可观性的监测过程。

2、检测和报警装置

一个基本的火灾探测系

统由两部分组成，检测和报

警。自动检测设备有比如热，

烟雾或火焰检测器，紫外线或

红外线探测器或火焰闪烁，是

基于检测 一个燃烧的副产品。烟雾探测器都电离和光类型，是最常用的检测设备。 当这种类型的典型探测器进入报警状态产生的电流信号会从PA变成MA （比如，从单纯的15pA在休眠模式下为60毫安）在主动模式。在许多探测器的检测器输出电压明确在各种运行条件，例如见表1。 越是敏感的检测器， 它更容易受到虚假警报。为了控制探测器的精确，可使用下列方法：过滤技术，这样的逻辑电路成为活跃仅当x警报的时间内检测周期T。检测技术在很大程度上取决于地点和植物受到保护，烟雾探测器是睡觉的地方，

红外线和紫外线辐射探

火灾报警器中英文文献翻译

测器，检测易燃液体燃烧，热探测器用于灭火和灭火系统。一般来说，生命和财产保护有不同的做法。报警装置，从通常的声响或视觉报警外，还可以采用固态的声音再现和紧急话音通信或打印机，记录时间，日期，地点和其他资料 。Heavisid [4] 拥有一支优秀的审查探测器和灭火器的各种制度。

2.1控制理念和分工

我们的理念是实施控制等级。 三个层次的系统级的实施， 两个级别的决策。之间没有设备 ， 在同一层次的沟通。 交互各级之间发生了向上的信息传输有关的子系统和向下状态转移的命令。这是图所示。1，其中第1级是中央控制站，是微机最终（在不手动模式）决策者。第2级是当地控制器，建立在当地的站。 第3级是实际检测器和驱动器。在各级提供手操作模式。所有探测器的数据和分处理器是当地控制的基础。他们将信息浓缩，并转交中央处理器。信息传递的地位始终是单向及以上。命令传输是单向的总是向下，并在扩大局部控制的水平。这种方法保留了层次的准确监测检测和严格的规则高风险的核电站警报系统。两个控制层的分类是基于决策层。

（一） 在届时的决定，提出和决定的执行情况不能再拖延

（二）决定的不确定性

（三）将隔离当地的决定（例如，我们可能会在当地报警，但有可能有故障系统）

火灾报警器中英文文献翻译

3、硬件

图.2描绘了我们的设计最简单的形式。这个系统采用四个导体开放的路线，在所有远程共享一个循环电缆设备和控制面板。这种方法简单，经济上可行。但是，一个主要缺点是对一个单一的电力和信号电缆的依赖。在重要环境下，可靠性是极其重要的。固可采用两个甚至三个电缆采取不同的线路连接，可并行连接。 图.3是驱动电路必须得一个扩展总线。采用这种设计在单片机技术的最新发展优势减少与中央控制站和地方控制站的接口。

3.1中央控制任务

中央站点提供了一个集中点，以监测和控制系统的活动。在该系统介绍了中央控制单元的目的

（一） 它得到了分控制站的信息和控制警钟及其他输出设备。

（二） 它提示在系统出现故障时的操作。

（三） 它提供了一个全面系统的手动和自动控制。

（四）， 它提供了中央和分站的系统测试点。

（五） 它提供了一个中心点观察，学习和适应。

火灾报警器中英文文献翻译