Abstract: This paper describes the building automation system components, functions, and principles of software and hardware technology, history, and related products are briefly introduced the reader of this system has a comprehensive understanding of relevant professional designers for the program designed to provide a theoretical frame of reference.
Keywords: building automation system, the core principle of the basic functions of hardware and software technologies
1 Introduction to Building Automation System, also known as building automation system (BuildingAutomationSystem referred to as BAS), is an integral part of intelligent building, its task is the building's energy use, environmental, traffic and safety monitoring, control, etc., to provide a safe and reliable, but also save energy, and comfortable work or living environment
2.building automation system components and basic functions of building automation systems often include air conditioning, water supply and drainage, power supply, lighting, elevators, fire safety and prevention and other subsystems. According to our industry standards, BAS can be divided into equipment operation management and monitoring subsystem and fire prevention and safety subsystems, as shown. In general, these two subsystems together into BAS consider should, if the fire and safety precautions Ziji Tong independent setting, control center should be established communication with the BAS contact Yipian disaster Fasheng, can achieve the agreed operating Quan Zhuan Yi An Zhao, Jin Xing Yi Tihua coordination and contro.
Building automation system's basic functions can be summarized as follows: (1) automatic monitoring and control of various electrical and mechanical equipment, the stop, display or print the current operating state. (2) automatic detection, display, print a variety of electrical and mechanical equipment operating parameters and changes in trends or historical data. (3) According to external conditions, environmental factors, the change automatically adjust the load of equipment, so that is always running in top condition. (4) monitoring and timely processing of all accident emergencies
(5) to achieve a variety of electrical and mechanical equipment on building a unified management, coordination and control. (6) Energy management: water, electricity, gas metering and charging, etc., to achieve energy management automation. (7) Equipment Management: including device files, equipment operation and
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equipment maintenance management reports. 3, the principle of building automation control system
Building control system used is based on modern control theory, distributed computer control system, also known as distributed control system (Distributedcontrol systems referred to as DCS). It is characterized by a \"centralized management decentralized control,\" that is charged with distribution of equipment in the field office of the micro-computer control (DDC) to complete device charged with the task of real-time detection and control, centralized control of computer to overcome the risks of high lack of centralized control and conventional single instrument limitations.Installed in the central control room of the central management computer with CRT display, print output, extensive software management and a strong digital communications capabilities to complete the centralized operation, display, alarm, tasks such as printing and optimal control, avoiding Changgui instrument control is distributed difficulties after the man-machine contact, no unified management shortcomings, ensure that equipment running in top form.
Here are distributed control systems with several concepts. 3.l direct digital control system (DDC) direct digital control system (Direct Digital Control referred to as DDC) shown in Figure 2. Computer through the analog input channels (AI) and digital input channels (DI) real-time data collection, and then calculated according to certain rules, and finally the control signals, and through the analog output channels (AO) and the switch output channel (DO ) direct control of the production process. So DDC system is a closed loop control system, a computer in the industrial production of the most popular way of an application
DDC system control computer to undertake tasks, which required real-time, high reliability and adaptability.
3.1.1 Composition of direct digital control system
Direct digital control system consists of the process input channel, process control computer, the process of output channels of three parts. Process input channels from the analog input and digital input of two parts. Analog input channels from the transmitter, the sampling switch, amplifier, A / D converter and interface circuit. One is the role of the transmitter signal will be converted into the standard non-power electrical signal，Can be temperature, pressure, flow transformed into 0-10mA or 4-20mA DC signal, it is through the A / D converter to achieve. - Digital input channels from the switch contacts, photoelectric coupler and interface circuit,
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reflecting the production process on / off state of the contact signal, through the optocoupler and the interface circuit transformation into a digital signal sent to the computer
Direct commitment to the process control computer operations and control tasks, first of all input channels through the process of collecting the parameters of the object and signals, then the scheduled control law (such as PID) for operation, and then send control signals to the controlled object, then the output channel direct control of the control valve actuator
Process output channel from the analog output and digital output of two parts. The former control of the computer output of digital signals into analog voltage or current signals, through the amplifier to drive the actuator control valve to achieve control of the production process. This part of the interface circuit, D / A converter, amplifier and actuator component. Which the computer output of the switch signal by amplifier to drive solenoid valve and relay actuator, which consists of electrical interfaces, optical coupler, amplifier and actuator component。
3.1.2 Direct Digital Control System in accordance with the deviation of the ratio of the basic algorithm (P), integral (I) and differential (D) control, a continuous system technology is mature, the most widely used as a basic law, the PID control Guilv discrete implementation of and make computer, can easily be accumulated to use this proven technology, but also the alleged target of the mathematical model or parameter is not very clear under the circumstances, Jing Guo-line tuning of Xiaoguo satisfactory. Therefore, the law regulating discrete analog digital PID algorithm, computer control of industrial processes have been widely adopted system, a DDC system, the basic algorithm
Digital PID control algorithm, analog PID controller ideal formula for the type of e (t) - deviation (set value and the actual output value of the error) u (t) - control the amount of Kp - Ti a scaling factor Integral time constant Td - differential time constant transfer function written in the form of a computer in order to achieve, must be a continuous form of differential equations into discrete form of differential equations. Set for the sampling period (compared with the system time constant, T is small enough), k is sampling number (k = 0,1,2, ... ...), can be calculated and rectangular plot to replace the differential difference Type in e (k) - k-th sample from the deviation e (k-1) - s (k-1) sub-sample from the deviation of u (k) - k-time control of traffic on the type of The smaller the sampling period T (comparison with the
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system time constant), was charged with the process and the continuous control process approached, also known as \"quasi-continuous control\"
3.2 The architecture of distributed control system distributed control system (Distributed Control Systems referred to as DCS) 20 century in the mid 70s and quickly developed, it will computer technology, control technology, graphics and communication technologies together in one , can spread over the scene of the equipment control, but also convenient to centralized management, operation, and the past, the control system, both to avoid Le single centralized computer control of the inadequacy of Overcome conventional human-computer interaction difficulties the shortcomings instrument .
Distributed control system of multiple micro-computer system to replace the centralized control of a single computer, from the architecture of the risk of dispersion, improved reliability,. The basic structure and function shown in Figure 3, the figure scene controllers, data acquisition station, engineer station, operator station, monitor and manage computer data communication through computer networks are organically combined to form the hierarchical distributed control system
3.2.1 A distributed control system data communications network Data communication network is a pillar of the distributed control system. The structure of the distributed control system, which is a network structure, the control station, data acquisition station, engineers, operator stations, monitoring station is the computer on the network \"node\special network address (nodes), can send and receive data through the network, the network of each node in equal status, can share resources and interdependent, form a unified command, and has the function of the dispersed risk, network architecture area is of great flexibility, scalability, can satisfy the distributed control system with the need to upgrade, the expansion is flexible and convenient(1) control network characteristics of distributed control system is different from the general computer network communication network, and general communication network, it is as follows: (1) have special requirements, high reliability and safety requirements of information transmission, therefore absolutely accurate, reliable and often USES redundant technology, backup and diagnosis function. Such as: control station adopt double CPU boards, double I / 0 plate, etc. 2 good performance. 3 strong adaptability to environment. (2) network topology construction equipment automation systems commonly used have bus network and ring network, in two kinds of structure of two
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nodes can be directly through the network communication, each node in equal status
(3) network communication protocol component architecture equipment automation system, there must be a kind of everybody can accept and abide by the working language to realize mutual dialogue, this is the data communication protocol standards. Used for building automation control network BACnet agreement by the physical layer, data link layer and network layer and network components, or the equivalent of open systems interconnection reference model (OSI) first, second, third, seven layer protocol Among them: ARCnet for token bus network, data transfer rate of 2.5-20bit/s, have a good time. MS/TP is a main/transmission from the data link layer technique, allows the use of EIA - 485 hardware. BACnet achieve different manufacturer of automatic control system of communication between technology, i.e., from a \"island\" to another \"island\" relationship between the technology
5 Conclusions building automation control technology in China is still an emerging technology, with the emergence of more intelligent building, there will be more advanced technology to add to this area, so the technology is more mature and improve
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智能楼宇自动化系统
摘要：本文详细介绍了楼宇自动化系统的组成、基本功能、原理、核心的软硬件技术、发展历史，并对相关产品做了简要介绍，使读者对该系统有一个全面的认识，也为相关专业设计人员的方案设计提供了理论上的参考依据。
关键词：楼宇自动化系统 基本功能 原理核心 软硬件技术 1 引言
楼宇自动化系统也叫建筑设备自动化系统(BuildingAutomationSystem简称BAS)，是智能建筑不可缺少的一部分，其任务是对建筑物内的能源使用、环境、交通及安全设施进行监测、控制等，以提供一个既安全可靠，又节约能源，而且舒适宜人的工作或居住环境。
2 楼宇自动化系统的组成与基本功能
建筑设备自动化系统通常包括暖通空调、给排水、供配电、照明、电梯、消防、安全防范等子系统。根据我国行业标准，BAS又可分为设备运行管理与监控子系统和消防与安全防范子系统，如图所示。一般情况下，这两个子系统宜一同纳入BAS考虑，如将消防与安全防范子系统独立设置，也应与BAS监控中心建立通信联系以便灾情发生时，能够按照约定实现操作权转移，进行一体化的协调控制。
建筑设备自动化系统的基本功能可以归纳如下：
(1)自动监视并控制各种机电设备的起、停，显示或打印当前运转状态。 (2)自动检测、显示、打印各种机电设备的运行参数及其变化趋势或历史数据。(3)根据外界条件、环境因素、负载变化情况自动调节各种设备，使之始终运行于最佳状态。
(4)监测并及时处理各种意外、突发事件。
(5)实现对大楼内各种机电设备的统一管理、协调控制。
(6)能源管理：水、电、气等的计量收费、实现能源管理自动化。 (7)设备管理：包括设备档案、设备运行报表和设备维修管理等。 3 楼宇自动化控制系统的原理
楼控系统采用的是基于现代控制理论的集散型计算机控制系统，也称分布式控制系统(Distributedcontrol systems简称DCS)。它的特征是“集中管理分散控制”，即用分布在现场被控设备处的微型计算机控制装置(DDC)完成被控设备的实时检测和控制任务，克服了计算机集中控制带来的危险性高度集中的不足和常规仪表控制功能单一的局限性。安装于中央控制室的中央管理计算机具有CRT显示、打印输出、丰富的软件管理和很强的数字通信功能，能完成集中操作、显
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示、报警、打印与优化控制等任务，避免了常规仪表控制分散后人机联系困难、无法统一管理的缺点，保证设备在最佳状态下运行。
以下介绍与分布控制系统相关的几个概念。 3.l 直接数字控制系统(DDC)
直接数字控制系统(Direct Digital Control简称DDC)如图2所示。计算机通过模拟量输入通道(AI)和开关量输入通道(DI)采集实时数据，然后按照一定的规律进行计算，最后发出控制信号，并通过模拟量输出通道(AO)和开关量输出通道(DO)直接控制生产过程。因此DDC系统是一个闭环控制系统，是计算机在工业生产过程中最普遍的一种应用方式。
DDC系统中的计算机直接承担控制任务，因而要求实时性好、可靠性高和适应性强。
3．1．1 直接数字控制系统的组成
直接数字控制系统主要由过程输入通道、过程控制计算机、过程输出通道三部分组成。
过程输入通道由模拟量输入和数字量输入两部分组成。模拟量输入通道由变送器、采样开关、放大器、A／D转换器和接口电路组成。其中变送器的作用是将非电量信号变换成标准电信号，可将温度、压力、流量变换成0-10mA或4-20mA的直流电信号，它是通过A／D转换器来实现的。—数字量输入通道由开关触点、光电耦合器和接口电路组成，反映生产过程的通／断状态的触点信号，经过光电耦合器和接口电路变换成数字信号送给计算机。
过程控制计算机直接承担运算和控制任务，首先通过过程输入通道采集被控对象的各种参数信号，再根据预定的控制规律(如PID)进行运算，然后向被控对象发出控制信号，再通过输出通道直接控制调节阀等执行机构。
过程输出通道由模拟量输出和数字量输出两部分组成。前者把计算机输出的数字控制信号转换成模拟电压或电流信号，再经过放大器去驱动调节阀等执行器实现对生产过程的控制。这一部分由接口电路、D／A转换器，放大器和执行器组成。后者把计算机输出的开关信号，经放大器去驱动电磁阀和继电器执行器，它由接口电器、光电耦合器、放大器和执行器组成。 3．1．2 直接数字控制系统的基本算法
按照偏差的比例(P)、积分(I)和微分(D)进行控制，是连续系统中技术成熟、应用最为广泛的一种基本规律，将PID控制规律离散化并在计算机上实现，可以方便地利用已积累的成熟技术，而且可以在被控对象的数学模型或参数不很清楚的情况下，经过在线整定达到满意的效果。因此，将模拟调节规律离散化的数字PID算法，已被工业过程计算机控制系统普遍采用，成为DDC系统的基本算法。
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数字PID控制算法，模拟量调节器的理想PID算式为 式中e(t)——偏差(设定值与实际输出值之差)u(t)——控制量Kp——比例放大系数Ti一积分时间常数Td——微分时间常数写成传递函数形式
为了能在计算机上实现，必须将连续形式的微分方程化为离散形式的差分方程。设了为采样周期(与系统时间常数相比，T足够小)，k为采样序号(k=0，1，2，……)，可用矩形法计算而积以差分代替微分式中e(k)——第k次采样所得偏差值e(k-1)——第(k-1)次采样所得偏差值u(k)——第k时刻的控制量
上式中的采样周期T越小(与系统时间常数比较而言)，则被控过程与连续控制过程越接近，又称为“准连续控制”。 3．2 分布式控制系统的体系结构
分布式控制系统(Distributed Control Systems简称DCS)20世纪于70年代中期出现并迅速发展起来，它将计算机技术、控制技术、图形显示技术和通信技术汇集于一体，可对分散在现场的设备进行控制，又可方便地集中管理、操作，与以往的控制系统相比，既避免了单台计算机集中控制的不足，又克服了常规仪表人机交互困难的缺点。
分布式控制系统的多台微型计算机取代了集中控制系统的单台计算机，从体系结构上分散了危险性，提高了可靠性。其基本结构功能如图3所示，图中现场控制站、数据采集站、工程师站、操作员站、监控计算机和管理计算机通过数据通信网络被有机地结合起来，组成分级分布控制系统。 3．2．1 分布式控制系统的数据通信网络
数据通信网络是分布式控制系统的支柱。整个分布式控制系统的结构，实质上是一个网络结构，现场控制站、数据采集站、工程师站、操作员站、监控计算机等都是这个网络上的“节点”，都含有CPU和网络接口，它们都有自己特定的网络地址(节点号)，可以通过网络发送和接收数据，网络中的各节点处于平等地位，既能共享资源，又不相互依赖，形成既有统一指挥，又使危险分散的功能结构，网络的架构区具有极大的伸缩性，可扩性很强，可以满足分布式控制系统扩充与升级的需要，十分灵活、方便。
(1)控制网络特点 分布式控制系统的通信网络不同于通用计算机网络，与一般的通信网络比较，它有如下特殊要求：①有高可靠性和安全性，要求传递的信息绝对准确、可靠，为此常采用冗余技术、后备措施和自诊断功能。如：控制站采用双CPU板，双I／0板等。②具有良好的实时性。③对环境适应性强。
(2)网络拓扑结构 建筑设备自动化系统常用的有总线网和环网，在两种结构中任意两节点通信可直接通过网络进行，各节点处于平等地位。
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(3)网络通信协议 组成建筑设备自动化系统，必须有一种大家都能接受并且共同遵守的工作语言来实现相互之间的对话，这就是数据通信协议标准。用于建筑自动化控制网络的BACnet协议由物理层、数据链路层、网络层和应用层组成，或相当于开放系统互联参考模型(OSI)的第一、二、三、七层协议其中：ARCnet为令牌总线网，数据传输速率为2．5-20bit／s，有良好的实时性。MS／TP是一种主／从令牌传递数据链路层技术，允许使用EIA-485硬件。BACnet实现了不同生产厂家自控系统之间进行通信的技术，即从一个“岛”到另一个“岛”之间进行相互联系的技术。
5 结束语
楼宇自动化控制技术在我国还是一个新兴的技术领域，随着更多智能建筑的出现，将有更加先进的技术补充到这一领域中，使这一技术更加成熟、完善。
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