1. Ing. Zbynek Zahradnik OPC Labs
QuickOPC 5.02
Ing. Zbynek Zahradnik
OPC Labs

2. Overview OPC (Data Access) – what is it
EasyOPC-DA: developer tool that provides access to OPC data
Basic design principles
Stateless model
Service-oriented
Support for widest selection of languages and programming tools:
COM: especially scripting tools (OLE automation),
.NET – any language
Easiness of use (short code)
Universally applicable (as much platforms as possible)

3. Features
Set of .NET classes, or “automation” COM objects with several methods and properties
Simplifies the OPC interface to the maximum
Automatically connects to OPC servers, and disconnects from them
Detects servers and connections that are not functional, and performs restarts and restorations to the original state
Automatically adds and removes OPC groups and items
Merges and optimizes requests from calling applications
Works as data cache
Automatically determines and changes the update rate of OPC items
Converts data types to a subset that is known to be supported in all tools (for .NET, those prescribed by CLS; for COM, VBScript being usually the most limiting)

4. Compatible tools and languages
.NET: C#
Visual Basic.NET (VB.NET)
J#, F# etc.
different hosts (Console, WinForms, WPF, ASP.NET, etc.)
COM:
VBScript (WSH, ASP, IE)
JScript (WSH, ASP, IE)
PHP (!)
Visual Basic 6.0
VBA (Word, Excel, PowerPoint etc., and applications from other vendors)
Visual FoxPro
C++ (in VS 6.0 or VS.NET 2003/2005/2008/2010)
Python
Delphi
LabVIEW
Many others (Xeneo Web Server etc.)

5. Integration with custom application
Example of very simple coding (C#):
// Create EasyOPC-DA component var EasyDAClient = new OpcLabs.EasyOpc.DataAccess.EasyDAClient(); // Read item value and display it in a message box MessageBox.Show(EasyDAClient.ReadItemValue("", "OPCLabs.KitServer.2", "Demo.Single").ToString());

6. Demo of usage in the app
„Demo“ from the installation

7. Background processing done by EasyOPC
Keeps track of (remote) comp[uters in use and connects to OPCEnum component on them. Automatically restores these connections in case of problems.
Keeps track of OPC servers in use, and maintains only one optimized connection to every server. Periodically checks status of OPC server and its connection, and automatically restores the connection in case of problems. Recreates the original state in the restored connection, so that ot contaisn the same groups and items as before the problem.
Satisfies the client app requests with data from cache, or creates new OPC groups and adds items as needed..
Optimizes adding new and removing old OPC items so that if possible, multiple items are being added (or removed) in one call.
Queues incoming values (callbacks) from connected OPC servers and processes them asynchronously.
Monitors usage of individual OPC items and modified its „update rate“ as needed. This requires creating new OPC groups or removing OPC groups that are no longer in use. Tato činnost vyžaduje též vytváření nových grup a rušení nepoužitých grup. „Update rate“ values that are close are put into common “buckets” in order to reduce the number of groups necessary.
Removes OPC items athat are not used for extended periods of time.
Disconnects from OPC servers that are not used for extended periods of time.
If the number of OPC servers or OPC items exceeds the pre-set capacity limits, removes or disconnects those that were not used for longest time period (LRU algorithm).

8. Applications Operator interfaces (HMI) to systems based on OPC
Specialized applications using OPC data (computational, monitoring, database, logging etc.)
Making OPC data accessible to tools that would otherwise be difficult or impossible
OPCDAAuto replacement
Recipes and batch processes
Testing of OPC Servers and devices
OEM products
other

9. Specifications
Will connect to all OPC Data Access (Custom Interface) 1.0x, 2.0x and 3.0x servers
Connects to OPC UA (Universal Architecture) servers through UA Proxy (included)

10. Licensing Trial License
Provides valid data for 30 minutes
OPC Labs can generate special trial license upon request
Commercial Licenses (.bin file for License Manager)
meant for System Integrators (SI)
per machine, or royalty free
see price list
Special Licenses:
ISV, OEM, VAR licenses

11. Installation Single file, can be placed on Web
needs certain Prerequisites
Installing will put on your computer:
EasyOPC-DA components
Simulation OPC Server
OPC Core Components
Documentation
and more
Bonus Pack:
Free tools
Examples in various tools and languages

12. OPC Item Generator
This tool generates code parts for the developer

13. Availability Trial version: On the Web for download
The licensed version is the same software, in addition the license must be installed on the computer running the component
Licenses generated individually by OPC Labs or by vendor
Delivered in form of .BIN file

14. PROGRAMMING

15. Object model The main object is EasyDAClient Helper objects:
Methods such as:
ReadItem (MachineName, ServerClass, ItemID [, AccessPath [, DataType]])
ReadItemValue (MachineName, ServerClass, ItemID [, AccessPath [, DataType]])
WriteItemValue (MachineName, ServerClass, ItemID [, AccessPath], Value)
GetPropertyValue (…)
SubscribeItem (…)
methods with “Invoke”: work asynchronously, be notified upon completion
methods with “Multiple”: work effectively with large amount of items
Browsing methods (for servers, branches or leaves)
Properties:
ClientMode (preferred access methods etc.)
HoldPeriods
UpdateRates
Timeouts
Helper objects:
VTQ (Value, Timestamp, Quality)
Descriptors, elements etc. – see documentation

16. OPC User Objects Set o = CreateObject("OPCLabs.UserBrowseServer")
o.MachineName = ""
o.RunMe
WScript.Echo o.ServerClass

17. Configurable Parameters
Some are in instance properties
Some are in static properties (.NET) or configurable through the tool (COM):

18. Troubleshooting
Error messages: find out as much as possible – not only error number, but also its text and additional information (e.g. Err.Source, Err.Description in VBScript)
Many errors may come directly from the OPC Server
Invoking problems, „Access denied“ and similar –DCOM
configuration, IIS configuration, user and file permissions
Slowness: improper settings or use of timeouts

19. DCOM and IIS issues
Be careful about user accounts under which the client application, EasyOPC and OPC Server run, sometimes even other components (e.g. OPCEnum)
Depending on IIS settings, EasyOPC may be called under specific authenticated user, or under the account configured for anonymous access

20. FUTURE

21. Version 5.10 and later OPC Alarms and Events (A&E) support
Native OPC Universal Architecture Client
usability improvements
advanced functions
return of the Web (?)

22. Additional information
Documentation in the product and on the Web
Online Forums

23. Conclusion
Questions
Discussion
Thank you!