1、Software for Automation:Architecture, Integration, and Securityberge front of book.qxd 1/27/2005 10:56 AM Page 1berge front of book.qxd 1/27/2005 10:56 AM Page 2Software forAutomation:Architecture, Integration, and SecurityJonas Bergeberge front of book.qxd 2/20/2007 10:08 PM Page 3Notice The inform
2、ation presented in this publication is for the general education of the reader. Because neitherthe author nor the publisher have any control over the use of the information by the reader, both theauthor and the publisher disclaim any and all liability of any kind arising out of such use. The reader
3、isexpected to exercise sound professional judgment in using any of the information presented in a partic-ular application. Additionally, neither the author nor the publisher have investigated or considered the affect of anypatents on the ability of the reader to use any of the information in a parti
4、cular application. The reader is responsible for reviewing any possible patents that may affect any particular use of theinformation presented. Any references to commercial products in the work are cited as examples only. Neither the author northe publisher endorses any referenced commercial product
5、. Any trademarks or trade names referencedbelong to the respective owner of the mark or name. Neither the author nor the publisher makes anyrepresentation regarding the availability of any referenced commercial product at any time. The manu-facturers instructions on use of any commercial product mus
6、t be followed at all times, even if in con-flict with the information in this publication. Copyright 2005 ISA The Instrumentation, Systems, and Automation Society All rights reserved. Printed in the United States of America. 10 9 8 7 6 5 4 3 ISBN-13: 978-1-55617-898-6 ISBN-10: 1-55617-898-0 No part
7、of this work may be reproduced, stored in a retrieval system, or transmitted in any form or byany means, electronic, mechanical, photocopying, recording or otherwise, without the prior written per-mission of the publisher. ISA 67 Alexander Drive P.O. Box 12277 Research Triangle Park, NC 27709 Librar
8、y of Congress Cataloging-in-Publication DataBerge, Jonas.Software for automation : architecture, integration, and security /Jonas Berge.p. cm.Includes bibliographical references and index.ISBN 1-55617-898-0 (pbk.)1. Automation-Data processing. I. Title. T59.5.B465 2005670.42755-dc222004030329berge f
9、ront of book.qxd 2/20/2007 10:08 PM Page 4DedicationFor the other half of the skyberge front of book.qxd 1/27/2005 10:56 AM Page 5berge front of book.qxd 1/27/2005 10:56 AM Page 6ContentsviiPREFACE xiChapter 1 INTRODUCTION AND OVERVIEW 1Automation Software, 2Software Hierarchy, 32History of Automati
10、on Software, 35Evolution of Software Architecture, 37Exercises, 40References and Bibliography, 41Chapter 2 BENEFITS, SAVINGS BACnetis a registered trademarkof American Society of Heating, Refrigerating and Air-Condi-tioning Engineers (ASHRAE); ControlNetis a trademark ofControlNet International Ltd.
11、; Delphiis a trademark of BorlandSoftware Corp.; DeviceNetand EtherNet/IPare trademarks ofODVA; FOUNDATIONFieldbus is a trademark of the FieldbusFoundation; HARTis a registered trademark of the HARTCommunication Foundation; InfoPlus.21is a registered trade-mark of Aspen Technology, Inc.; IPX/SPXis a
12、 trademark ofNovell, Inc.; Javais a trademark of Sun Microsystems;NASDAQis a registered trademark of The NASDAQ StockMarket, Inc.; and Unixis a registered trademark of Unix SystemLaboratories, IncPreface xiiiberge front of book.qxd 1/27/2005 10:56 AM Page xiiiberge front of book.qxd 1/27/2005 10:56
13、AM Page xivIntroduction andOverview11In the past, a process plant was operated from gauges and valvesright on the processing equipment by operators with clipboards.Later, pneumatic and analog electronic signals enabled largecentralized control panel boards with all buttons, switches,annunciator ligh
14、ts, indicator stations, chart recorders, andcontroller faceplates in a central location. Process flow was shownon a board, possibly a mosaic display including some indicators,buttons, and other features (Figure 1-1).Figure 1-1. Control Panel Board Distributed Control System (DCS) entered the process
15、 controlmarket in the mid-1970s, using simple communications to aprimitive character-based operator display with only a few colors.At the same time, the Programmable Logic Controller (PLC)entered the manufacturing automation market. In the mid-1980s,PLC with communications opened the market for Huma
16、n-Machine Interface (HMI) automation software based on DOS (firstberge chap 1.qxd 1/27/2005 10:55 AM Page 12 Software for Automationknown as MMI for Man-Machine Interface), HMI or SupervisoryControl and Data Acquisition (SCADA) software. Systemsintegrators could write communication driver software f
17、or HMIapplications to interface with all kinds of hardware such ascontrollers, Remote Terminal Units (RTUs), weighing scales, andother equipment. PLCs with HMI consoles began to challengeDCS in the process control market. DCS went through an era ofexpensive Unix-based consoles, and in those days PLC
18、 with HMIon cheaper computers was called a “PC-based” solution.Today most automation systems, including most remaining DCSs,use MicrosoftWindows operator consoles based on NTtechnology, including Windows 2000 and XP. Fieldbus networkingand software continue to go hand in hand since together theymake
19、 up the information infrastructure of the plant. Fieldbusradically changed the way plants operate by adding an “alwayson” link to every device in the plant. As fieldbus networks getfaster and more advanced, software too gets more sophisticated toshow the increasing amounts of data. System engineers
20、now morethan ever need to understand the available software technologiesin order to make the correct choice.Automation SoftwareApart from the configuration tool, the primary automationapplication is the operator visualization software. Other softwareincludes specialized ancillary applications for au
21、to tuning, advancedcontrol, Enterprise Resource Planning (ERP), simulation andoptimization, inferential measurements, plant information, batch, andStatistical Process Control (SPC). All these applications rely on datafrom the plant floor and therefore have to interface to the devices forbasic contro
22、ls, shutdown system, turbines and compressor controls,legacy DCS or PLC, as well as other buses and equipment.Information ArchitectureCorrect operator actions, technician activities, and businessdecisions depend on information from the plant floor. It istherefore important to build an information ar
23、chitecture thatcaptures data from the field and disseminates it throughout theenterprise. The data is distilled as it percolates through theautomation, execution, and business levels. Data like “PV,”“status” and “mode” must be distilled into information useful fordifferent people. For example, press
24、ure, temperature, level,density, and interface level readings of a dozen tanks areberge chap 1.qxd 1/27/2005 10:55 AM Page 2Chapter 1 Introduction 3computed into a picture of the inventory. Thus information froma hundred sensors may become a single value more meaningfulfor a manager. At higher level
25、s, decisions are made based on“live” Key Performance Indicators (KPIs) such as quality, assetutilization, efficiency, and yield. Networking and software has tobe chosen to enable calculation of the required KPIs. Other datasuch as production rate and inventory are also important.A modern plant must
26、have an open network infrastructure thatreaches from the sensors and actuators all the way up to theexecution and business levels, permitting hardware from differentmanufacturers to communicate. Similarly, a plant must have anopen software infrastructure starting from the automation systemall the wa
27、y up to the ERP and supply chain applications.Therefore a modern plant requires the use of standards-basednetworking, with a standard application layer, and then softwareinterfaces on top of that.A major advantage of software is that lots of information can beprocessed and displayed in a comprehensi
28、ble way. Large screensand well-organized displays are required to show large amountsof information brought in by modern fieldbus networks withoutcausing clutter. Online data can be shown as dynamic displaysmimicking the process, manufacturing line, or building. Displayscan mimic traditional lamps, s
29、witches, and controller faceplates,etc. Data and events are automatically logged and displayed astrend plots, summarized in reports, or analyzed. Higher-levelcontrol functions such as batch management and multivariableoptimization can be done in software. Without powerful software,it is impossible t
30、o benefit fully from intelligence in fieldbusdevices, for example. For any system larger than a handful ofloops, software is a better operator interface than panelinstruments.Electronic record-keeping (i.e., database storage instead ofrecorder charts and log sheets) is another important aspect ofsof
31、tware. Electronic record-keeping requires database engineswith open interfaces that can accept information from differentsources and make it available to other applications for analysis. Aregulation like FDA 21 CFR Part 11 (Food and DrugAdministration, Code of Federal Regulation, Title 21) requires
32、allrelevant production data to be stored securely for audit. berge chap 1.qxd 1/27/2005 10:55 AM Page 34 Software for AutomationFundamentalsUnlike old panel instruments, good software does not trap datainternally, but makes information easily accessible so that it caneffortlessly be shared among tho
33、se who need to know. Forexample, manufacturing line status and process alarms go to theoperators, device diagnostics and fault events to the technicians,and reports to the management. Used correctly, this informationcan lead to many savings. Modern IT includes several applicationinterface technologi
34、es to make this possible. Standard softwareinterfaces permit applications to share and exchange data. Thesetechnologies are like a “software DIN rail” that permits softwareto be installed and to share data just like signal conditioners pluginto the back of a control panel.Operating SystemAutomation
35、software runs on the computer operating system(OS). In the past, this was DOS, Unix, or others. Now thedominant OS in automation is the NT family of MS-Windows,which includes 2000 and XP. Some perceive Linux as a futurecontender. Windows provides application interface technologiesthat have paved the
36、 way for many software applications.Automation software today is easy to use, providing richfunctionality by taking full advantage of NT. The platformincludes Distributed Component Object Model (DCOM) client-server architecture, security, LAN, Internet, and dial-up modemnetworking, remote access ser
37、ver (RAS), terminal server, monitorand graphics, sounds and multimedia, pointing devices such asthe mouse, database, fonts, and printing. It is easy to connect anopen system to telecommunication systems for remote access.It may be a good idea to stick to a single operating system for allcomputers at
38、 the automation level, although computers at the executionand business levels can be a mix of other operating systems.Client-Server Architecture (COM, DCOM)Most software today is based on client-server architecture. Theserver software typically connects to the hardware or databasedata source. The se
39、rver usually does not have a user interface (i.e.,typically cannot be seen on the computer screen). However, theserver may have a separate configuration application. The clientapplication is typically a user interface that permits display anddata entry. The client and server communicate across a sof
40、twareberge chap 1.qxd 1/27/2005 10:55 AM Page 4Chapter 1 Introduction 5interface. The COM (Component Object Model) client-servertechnology is the basis for interface technologies such as ObjectLinking and Embedding for Process Control (OPC) and OLE_DB.Microsoft COM is the worlds leading component te
41、chnology.Clients and servers can exist in the same computer or on differentcomputers on the same control network linked through DCOM.This technology permits a client to start and stop a serverremotely and to exchange data, etc. DCOM uses any lower-levelnetwork protocol supported by Windows. This is
42、usually TCP/IPon Ethernet, but can be IPX/SPX or NetBIOS, etc. Clearly, TCP/IPon Ethernet is advantageous since it can then share infrastructurewith industrial protocols such as FOUNDATION Fieldbus HSE(Figure 1-2). Moreover, TCP/IP is also the standard in informationand business IT networks and of c
43、ourse on the Internet. Note thatCOM+ is not a souped-up version of COM; it is really a laterversion of Microsoft Transaction Server (MTS).Figure 1-2. Automation System HardwareIn an automation system, one or more of the computers operate ina server role. Work is carried out from client applications
44、in thesame computers or one or more workstation clients typicallylocated in the control room.In the past, most applications such as HMI communicated withhardware such as a PLC using custom-programmed drivers.Today the OPC specification is the leading client-servertechnology tailored specifically for
45、 automation. OPC is anapplication interface between software built on Windows DCOMreplacing traditional drivers. The client and server software maybe running in the same computer or on different machines on acontrol network. The client reads and writes to database andhardware through the server. The
46、re are different forms of OPCberge chap 1.qxd 1/27/2005 10:55 AM Page 56 Software for Automationtailored for specific tasks (Figure 1-3). The most notable are DataAccess (DA), Historical Data Access (HDA), and Alarms andEvents (A really the devicehas a server application that is OPC-compliant (Figur
47、e 1- 4).Figure 1-4. OPC Is a Software InterfaceOne of the most useful features of OPC is the tag browserfunction. It permits OPC client applications to see what OPCservers are available in the system, and what data is availablefrom each server. The user can pick data of interest simply bypointing an
48、d clicking (Figure 1-5).Figure 1-5. Universal Tag Browser (SMAR SYSTEM302)berge chap 1.qxd 1/27/2005 10:55 AM Page 78 Software for AutomationAn OPC server is made for each communication protocol andhardware combination. All the devices on the network using thespecific protocol are accessed through t
49、he same shared OPCserver; it is not necessary to have one OPC server for everydevice. For example, there may be one server for FOUNDATIONFieldbus (Figure 1-6) and another for Modbus. Note that the OPCserver may also be hardware specific. For example, a PROFIBUS-DPinterface card from one manufacturer needs a different OPCserver from a PROFIBUS-DP card from another manufacturer.Some network technologies use standard interface hardware suchas a regular Ethernet NIC or serial port, in which case an OPCserver works with any such interface hardware (e.g., FOUNDATIONField
