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Internet and web technology for use in plant automation
Copyright COl IFAC Future Trends in Automation in Mineral and Metal Processing. Finland. 2000
INTERNET AND WEB TECHNOLOGY FOR USE IN PLANT AUTOMATION
Dr. Andreas Hambrecht
ALSTOAI Power Conversion, Berlin, Germany
Abstract: A trend can be seen that more and more intranet, internet and web philosophy and technology is used for applications in automation. This paper describes a solution in an automation environment which uses the advantages of internet and web technology. The structure of a web based system and some applications are described. Copyright @ 2000 IFAC Keywords: Internet, Web, Automation
Many applications can be found in the web. These applications can be adapted to a specific problem. Development costs decrease. The web and internet technology also saves costs for tools and licences.
1. INfRODUCTION Web and internet technology offers a couple of benefits. The solutions are independent of hardware (e. g. DEC, PC, HP) and independent of operation systems (e. g. HPUNIX, LINUX, YXWORKS, WinNT). The web forces world wide standardisation of tools, browsers, interfaces, handling, and communication protocols. These standards make the web working. The standards are independent of a particular company or a particular supplier. The use of these standards is the base of communication in the web. The web technology supports a decentralised and heterogeneous system architecture. It is able to connect and integrate a wide range of services (figure 1).
2. FIELDS OF USE OF INTERNET AND WEB TECHNOLOGY An overview is given in fig. 1. It shows a sample of services which can be accessed in a plant automation. Web technology can be used as HMI (Human Machine Interface) for operators of a plant. For this application a limit is given by the display update rate. Less critical applications are production data management and display (process computer, production planning system or general database interfaces).
Teleservice, telemaintenance and remote support are easy to realise with web and internet technology. Access is possible at all levels (control equipment, basic automation system, drives, process computer, intelligent sensor, operating system etc.). A comprehensive plant status can be 'obtained. The distance from where the access is done is only limited by the communication infrastructure. There is no difference in the handling if the operator sits in front of a cubicle on site or far away somewhere in the world.
Web technology can be used for diagnosis and diagnostic and maintenance data display : • display of signal traces and trends • event recorder display • display of statistics and long term trends • statistical process control and process quality analysis • operating system and hardware system status display,debugging and maintenance (Fig. 3)
107
upper part of the left hand side of the screen filter and report definition are selected. Below on the left hand side a list of data sets is displayed, for which a report is produced. The list of data sets is set up using the selected filter criteria. The right hand displays the detailed report. In the background the data of a cold rolled coil are displayed as HTML-document. A PDF-file contains graphical of the coil. This information is shown in the foreground in an Acrobat Reader window.
• reports: - quality reports - engineers reports (Fig. 5) - production tracking and monitoring re port For diagnosis and data mining a diagnostic search engine helps to surf, search and navigate in the diagnostic data and the plant documentation. Hyperlinks are one simple way to navigate in documents. The diagnostic search engine simplifies and reduces the time needed for fault fmding and correction.
5. RISKS AND LIMITS IN USING WEB TECHNOLOGY
3. GENERAL LAYOUT IN A WEB BASED SYSTEM
The web teclmology was designed for open and not for secure communication. But for this problem solutions are available. Safety is assured by network topology and software. The authorised access to the web services is realised using password protection callback features and SSL encrypted data transmission. To secure the web servers the network services like FTP, telnet, secure shell, remote services etc. which are not used in the application are disabled. With the use of internet teclmologies it is possible to use all security solutions available for internet servers and networks, i. e. frrewalls, packet filter etc.
Figure I shows a general layout of a web based system. Each web client is equipped with a standard internet browser. For special functions plug-ins are downloaded. Web servers are installed on the different hardware platforms and offer a standardised interface to the outside world. For communication a local area network or a wide area network is used. Figure I does not display all details of the network. In reality the network can be combined by different communication media: fieldbus, ethernet, ISDN, internet provider etc. Suitable design connects all the network components using gateway, bridges, routers frrewall and access permission.
The web teclmology was also not designed for high speed display. The limits here are given by the performance of the communication network. As mentioned above, network topology is used to find an optimum. But because of communication performance restrictions today web and internet technology is only used for offline display like in the examples given in the figures 2 to 5.
In theory it is possible for each web client to access all servers in the network. In practise it is necessary to limit and control access. Therefore some clients are dedicated to a special task. With password protection or a suitable network architecture access to servers can be limited. The number of clients is only limited by network performance and network configuration. Network topology together with the limited access to services helps to improve performance and response time. For connections with high communication load separate network segments are used.
6. SUMMARY In general the web and internet technology offers new functionality to existing and new automation solutions and applications. Standardisation across platforms and automation solution suppliers offers new opportunities. A well-known standardised handling and operating philosophy across platforms and suppliers can be achieved. Easy integrating of distributed, heterogeneous and multi-platform solutions is possible. Telemaintenance and teleservice become standard features. World wide support can be offered and is available. In future web and internet teclmology will become more and more important in the field of automation. The web teclmology helps to integrate future automation applications, as described here, and commercial applications.
4. APPLICATION EXAMPLES In figures 2 to 4 some application examples are shown. Figure 2 shows a login screen. It gives access to a system monitor. After login for example the system resources are displayed. Figure 3 shows a process directory of the operating system. Figure 4 shows a display of status and error flags. In the lower section of the screen a list box is included. A message is selected with the list box and additional parameters on the right. This message is sent to the process. With these messages a debugging of the process is done. A more complex display is shown in figure 5. The process computer report browser is displayed. In
108
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ProcessDiagnostic and Analysis system
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FBD Engineering Parameters Runtime system
Production planning system
SPC server
Maintenance planning system
Statistical Process control (SPC) server
Fig. 1 General layout of web technology automation
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INTERNET AND WEB TECHNOLOGY FOR USE IN PLANT AUTOMATION
Dr. Andreas Hambrecht
ALSTOAI Power Conversion, Berlin, Germany
Abstract: A trend can be seen that more and more intranet, internet and web philosophy and technology is used for applications in automation. This paper describes a solution in an automation environment which uses the advantages of internet and web technology. The structure of a web based system and some applications are described. Copyright @ 2000 IFAC Keywords: Internet, Web, Automation
Many applications can be found in the web. These applications can be adapted to a specific problem. Development costs decrease. The web and internet technology also saves costs for tools and licences.
1. INfRODUCTION Web and internet technology offers a couple of benefits. The solutions are independent of hardware (e. g. DEC, PC, HP) and independent of operation systems (e. g. HPUNIX, LINUX, YXWORKS, WinNT). The web forces world wide standardisation of tools, browsers, interfaces, handling, and communication protocols. These standards make the web working. The standards are independent of a particular company or a particular supplier. The use of these standards is the base of communication in the web. The web technology supports a decentralised and heterogeneous system architecture. It is able to connect and integrate a wide range of services (figure 1).
2. FIELDS OF USE OF INTERNET AND WEB TECHNOLOGY An overview is given in fig. 1. It shows a sample of services which can be accessed in a plant automation. Web technology can be used as HMI (Human Machine Interface) for operators of a plant. For this application a limit is given by the display update rate. Less critical applications are production data management and display (process computer, production planning system or general database interfaces).
Teleservice, telemaintenance and remote support are easy to realise with web and internet technology. Access is possible at all levels (control equipment, basic automation system, drives, process computer, intelligent sensor, operating system etc.). A comprehensive plant status can be 'obtained. The distance from where the access is done is only limited by the communication infrastructure. There is no difference in the handling if the operator sits in front of a cubicle on site or far away somewhere in the world.
Web technology can be used for diagnosis and diagnostic and maintenance data display : • display of signal traces and trends • event recorder display • display of statistics and long term trends • statistical process control and process quality analysis • operating system and hardware system status display,debugging and maintenance (Fig. 3)
107
upper part of the left hand side of the screen filter and report definition are selected. Below on the left hand side a list of data sets is displayed, for which a report is produced. The list of data sets is set up using the selected filter criteria. The right hand displays the detailed report. In the background the data of a cold rolled coil are displayed as HTML-document. A PDF-file contains graphical of the coil. This information is shown in the foreground in an Acrobat Reader window.
• reports: - quality reports - engineers reports (Fig. 5) - production tracking and monitoring re port For diagnosis and data mining a diagnostic search engine helps to surf, search and navigate in the diagnostic data and the plant documentation. Hyperlinks are one simple way to navigate in documents. The diagnostic search engine simplifies and reduces the time needed for fault fmding and correction.
5. RISKS AND LIMITS IN USING WEB TECHNOLOGY
3. GENERAL LAYOUT IN A WEB BASED SYSTEM
The web teclmology was designed for open and not for secure communication. But for this problem solutions are available. Safety is assured by network topology and software. The authorised access to the web services is realised using password protection callback features and SSL encrypted data transmission. To secure the web servers the network services like FTP, telnet, secure shell, remote services etc. which are not used in the application are disabled. With the use of internet teclmologies it is possible to use all security solutions available for internet servers and networks, i. e. frrewalls, packet filter etc.
Figure I shows a general layout of a web based system. Each web client is equipped with a standard internet browser. For special functions plug-ins are downloaded. Web servers are installed on the different hardware platforms and offer a standardised interface to the outside world. For communication a local area network or a wide area network is used. Figure I does not display all details of the network. In reality the network can be combined by different communication media: fieldbus, ethernet, ISDN, internet provider etc. Suitable design connects all the network components using gateway, bridges, routers frrewall and access permission.
The web teclmology was also not designed for high speed display. The limits here are given by the performance of the communication network. As mentioned above, network topology is used to find an optimum. But because of communication performance restrictions today web and internet technology is only used for offline display like in the examples given in the figures 2 to 5.
In theory it is possible for each web client to access all servers in the network. In practise it is necessary to limit and control access. Therefore some clients are dedicated to a special task. With password protection or a suitable network architecture access to servers can be limited. The number of clients is only limited by network performance and network configuration. Network topology together with the limited access to services helps to improve performance and response time. For connections with high communication load separate network segments are used.
6. SUMMARY In general the web and internet technology offers new functionality to existing and new automation solutions and applications. Standardisation across platforms and automation solution suppliers offers new opportunities. A well-known standardised handling and operating philosophy across platforms and suppliers can be achieved. Easy integrating of distributed, heterogeneous and multi-platform solutions is possible. Telemaintenance and teleservice become standard features. World wide support can be offered and is available. In future web and internet teclmology will become more and more important in the field of automation. The web teclmology helps to integrate future automation applications, as described here, and commercial applications.
4. APPLICATION EXAMPLES In figures 2 to 4 some application examples are shown. Figure 2 shows a login screen. It gives access to a system monitor. After login for example the system resources are displayed. Figure 3 shows a process directory of the operating system. Figure 4 shows a display of status and error flags. In the lower section of the screen a list box is included. A message is selected with the list box and additional parameters on the right. This message is sent to the process. With these messages a debugging of the process is done. A more complex display is shown in figure 5. The process computer report browser is displayed. In
108
Web clients, general access
I
I Web browser
Web clients , dedicated to a task
I
I
Web browser
Web browser
General access to : Maintenance and diagnostic servers, Data Logger, event recorder etc.
I
I
I
Web browser
Web browser
Web browser
Web browser
Operators interface
Process Computer interface
HMI Human Machine interface
Engineering interface
Process engineering interface Reports (engineers reports, trend display, quality reports) and data base interface
Internet gateway
other services Firewall, Pakket filter. ..
-Ill
7
Internet
.
Modem, ISDN ,xDSL ...
l
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ProcessDiagnostic and Analysis system
PLC and HPC High performance controller
Data Logger
Event recorder and Trend server
Human Machine Interface (HMI)
Process engineering server
Operators Interface
Process computer operating system
Web camera, Intelligent sensors, Web telephone
FBD Engineering Parameters Runtime system
Production planning system
SPC server
Maintenance planning system
Statistical Process control (SPC) server
Fig. 1 General layout of web technology automation
109
Bitu l.dentlhneren Sle
~neh
und gebeJ'l sie Ihr Pa5svort eiJ'l
, Tuesday, 10-Aug-99 20.11:30 MET DST ~ 1999 AlSTOMl AS E44
Fig. 2 Login screen
Process Directory SI pid
o 2
4 6
8 10 12 14 16 18 20
22 24 20 28 30
32 34 30 38
la.st life sign SI pld 26AprOO 11 44: 43, 817 1 112 44:47,046 3 111 ",~!:;~~
89 105 117
125 128 131 133
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s2s [none] [ none] [ none ] [ none] [none] [none] [ none ] [ none ] [none] [none] [ none ] [ none ] [ none ]
Fig.3 Process directory display
1 I ()
26AprOO 11: 44: 45,926 26AprOO 11 :44:25,876 26AprOO 10:52:46.416
(x>ntents slot
Process
of
f
version CKETII099
into
cmxethd PlD
Instances Timeout priorlty
kpe5
09Nov99
command reg param
quit reg param error
00111 01 of 01 10,000 -00005
serial. 10035001
date
................................•
0 0 26AprOO 11: 45: 14,197
issued
...............................,.
.......................
110987654321098765432109876543210 _____ 1-_3 _________ 2 _________ i __________ T1 state 11 ••••••.••.•••••• ••••• •. ••••. 1 •• 1 f lags I .. ·· ·· .. · · .·· ... · .... · .. 1 debugl . . .. . ... . .•... .. .. .• . · . ..•. . ... ·1 - - -- -+ - -- ----- - -- - -- - - - -- - -- - - - - --- - --+
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active since 26AprOO 10:52 :1 2,687 las t ll fesign lssued 26AprOO 11: 45: 14,178
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optional Pat31T1 : lIJxO
.
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Fig. 4 Process status display
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