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Developing OPC HMI for a Web Browser Colin Winchester VP Operations Nathan Pocock Chief Architect & Developer
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Developing OPC HMI for a Web Browser Agenda – 60 Minutes u Overview of Web based HMI’s u Overview of the OPC Data. Hub u Live Demonstration u Overview of OPCSystems. NET u Live Demonstration u Additional Information u Questions & Answers
OPC to Browsers Why? u Availability u u Portable Access u u u Cell-phone based web browsers Handheld devices Network Access u u u Everyone has a browser Everyone knows how to use one Avoid special software installs, sometimes Standard transport protocols = firewall friendly Usually can handle slower connections better than a “thick client” application Administration & Development u u Single application updates all clients Development is easier than ever!
Web-App Capabilities u u Display data from OPC Servers Get user-input for writing to OPC Items Trending/Charting live OPC Data Alarm displays and acknowledgements
Example Configurations GREEN ZONE Browsers inside the network Browsers outside the network Single Server Solution OPC Systems Tag Repository OPC Server? Web Server Web Application Firewall First-line of defense from outside world. Secure access?
Example Configurations OPC Cluster high availability for your OPC Server(s) GREEN ZONE and/or OPC Systems. NET Tag Repository Tolerance Achieved: u. OPC Layer u. Web Servers Web Server Cluster high availability for your Web HMI application(s)
Web Challenges u Security/Networking u u Controlling the number of connections to the server Controlling access u u Speed – data update rates u u Aren’t the fastest at executing client side code Aren’t good at remembering “state” or “where I’ve been” u u Firewall Password Encryption of data (SSL) Cookies, query strings attempt to work around this! Wide variety of versions and service pack levels
OPC Data. Hub Functionality Overview OPC to Web System Monitoring http: //www. softwaretoolbox. com/opcdatahub
What can you do? Multiple & Varied Data Sources System Data u. PC uptime u. Running processes u. Memory usage Web Server OPC Data. Hub HMI Client
OPC to Web Methods ASP – Active Server Pages u u u Webserver reads some “live” or active data one time, and puts it into the web page No client side plug-ins or Active. X required Easy to implement Easy on system resources – client and server Requires page reload to refresh data Good for reports or one-shot, one-off data needs OPC Servers (1 to N) Local or Remote/Tunneled OPC Data. Hub Standard Web Browsers on Desktop or Mobile Devices Processing of data in Data. Hub on Server Side and value inserted into HTML web page
OPC to Web Methods Java Applets u u u Java Applets are another alternative Very, very fast update rates Very thrifty on server and client side compared to AJAX Speed of AJAX with thriftiness of ASP But you will have to allow the Java Applets to install Used in process control systems for monitoring and HMI displays OPC Servers (1 to N) Local or Remote/Tunneled OPC Data. Hub Standard Web Browsers w/ Java on Desktop PCs only Method #2 #1 IIS or Apache Web. Server serves up web pages Data. Hub Web. Server serves up web pages
Developing OPC HMI for a Web Browser u Live Demo u u OPC Data. Hub with ASP OPC Data. Hub with AJAX u u u Polling Streaming OPC Data. Hub with Java Applets
Summary of Web Methods ASP AJAX – Polling AJAX - Streaming Java applets Browsers Desktop and Mobile Desktop Only Plugin/Active. X required No No No Yes, Java plug-in Slow-manual page refreshes required Fast updates Very low on client and server Relatively high Moderate to low Yes Yes Yes – simply open port 80 Dedicated Port # must be opened Web Server and Node License + TCP License for each Concurrent connection VB Script Uses Java. Script Requires Java to build custom applets Update Speeds System Resources Security Password/SSL Firewall Friendly Licensing Programming Language
Web Development Changed u Code-less, no more learning “languages” u AJAX delivers dynamic pages, no reload u Winform/Webform development = same! u Easy debugging with Visual Studio. NET u Live OPC data in the Browser is now Easy!
Web-HMI, does it make sense? When it makes sense u u Simple screens with few graphics Data response can be slow Restrict access to users/groups Must be accessible u u Inside/outside LAN Desktop, Laptop, Phone etc. Not a good fit! u u High-speed data (sub 1 -second) Large quantities of data on-screen. High concurrent user # with above. Continuous process control / monitoring
OPC Systems. NET Benefits OPC Systems. NET provides these benefits: u Central “always-on” tag repository = faster performance u Tag data can come from OPC DA, UA* and/or Databases u Multi-Threaded for faster, and more Reliable operations u Buffers data, eliminating data-loss for short outages as well as maximizing the performance of your web-link u Modular, components available separately or as a suite u Affordable, not as expensive as you might think u OPC Self-Certified, for assurance in quality * While OPC UA is not yet released, OPC Systems. NET was one of the first to implement OPC UA back in 2006 and will support OPC UA once the OPC Foundation releases the necessary Tools.
How it works… u Tag repository stores Data, and some history u Data can come from OPC Servers (DA, UA etc. ) u OPC Connection is always ON eliminating connectivity overhead u u Browsers see OPC Data when page opens Async polling retrieves data to be shown in page, no refresh! AJAX Polling OPC Systems. NET Service (Tag Repository) Data Source OPC Server PLC DCS Other
How it works… u u Browser requests an “update” of the items/tags it needs. OPC Systems. NET Server responds with values that have changed: u u u If value remains same, empty data-set returned If 1 -value changed, that value is returned If the value changed multiple times, all updates sent AJAX Polling OPC Systems. NET Service (Tag Repository) Data Source OPC Server PLC DCS Other
Live Demo u Create a multi-page Web Site u Use Visual Studio. NET 2005 Master Pages u Display some (almost) real-time data u Simple Form Controls u Charting page u Alarm display and acknowledgement page
Tolerance OPC Systems. NET Service (Tag Repository) Queue u Network Internet Client Application u Queue Local u Queue Client Application Tag Repository individually “caches” data to each client If a client goes temporarily offline, it will “catch-up” on the next update. Applies to ALL OPC Systems. NET Clients (data logging, alarms, Win. Forms, Web. Forms etc. )
Other Features Available u u u Data Logging (text files and databases) Report generation Alarm logging and notification Windows Forms development tools Recipe management Lightweight HMI developer studio
Summary u Convenience: Quickly and easily build & deploy HMIs u Scalable Framework: allowing your system to grow u Reliable: OPC Self-Certified, plus Buffering u Alerting: Data Logging, Reporting, Alarming & Notifications u Open: API provides interface for your apps to control u Affordable: modular, buy what you need.
More Information … get through to an expert! Visit www. softwaretoolbox. com/webinars for future events Questions: Nathan Pocock: Email: [email protected] com Tel: +1 (704) 708 -6482 www. softwaretoolbox. com/opcsystems Colin Winchester Email: [email protected] com Tel: 704 -849 -2773 x 1327 www. softwaretoolbox. com/opcdatahub Technical Support: Tel: +1 (704) 849 -2773 Web: http: //support. softwaretoolbox. com
Affordable u License the entire system for just $1, 995. 00 u No OPC Server Connection or Tag Counts u No Client counts at the OPCSystems Service u No Text File or Database Connection Counts u Code-less development tools are Runtime-free u Fully documented, lots of examples u Smart. Client Technology ready
What Tools are Needed? ASP or AJAX Polling Scenario $995 $3750 u u Unlimited # of client connections OPC bridging, scripting, aggregation & Excel connections are included! No license limits on # of OPC items you access! No Server Operating system required
What Tools are Needed? AJAX Streaming and Java Applets w/Data. Hub Web. Server $995 $595/ea $3750 u u No Server class Operating System Needed! i. e. Run on Windows XP TCP/Link Licenses are concurrent connection licenses Data. Hub other features included! No license limits on # of OPC items you access!
What Tools are Needed? Java Applets w/IIS or Apache Web. Server serves up web pages $995 $595/ea $3750 u u u IIS or Webserver may be free, but will require IT involvement IIS is not really “free” – requires a Server Grade Operating System And, IIS & Apache present much bigger attack surface TCP/Link Licenses are concurrent connection licenses OPC bridging, scripting, aggregation & Excel connections included! No license limits on # of OPC items you access!