The OPC XML DA, OPC Xi and OPC UA specifications overlap but each one has different advantages and disadvantages and they will probably coexist. The strength of XML DA is its simplicity. It supports only the OPC Data Access (DA) functionality and as a.NET2 web service it’s restricted to HTTP communication.
MatrikonOPC Explorer is a free OPC Client packed with functionality for testing and troubleshooting OPC servers and OPC connections. Unlike other OPC clients, MatrikonOPC Explorer installs easily and provides results quickly thanks to its intuitive user interface and streamlined workflow. OPC UA C++ Client Toolkit for Linux, single seat developer license, source format, available only in combination with LMA-DD-035231 LMA-DD-035232 Service and Support Contract for OPC UA C++ Server Toolkit for Linux, 3 years minimum period, based on yearly fee.
This is comparably slow but still fast enough for many applications. Is a bit more complicated because it supports also Alarm&Events and Historical Data, has built-in security features and, based on WCF (Windows Communication Foundation), can be configured for wide range of communication protocols. For data exchange with non-Windows platforms the protocol selection is limited to HTTP. Xi is designed as an OPC.NET interface but code for other platforms can be created from the WSDL file, as with XML DA. For Windows platforms greatly simplify the server and client development. OPC UA is designed for multi-platform use and has its own communication stack.
UA is also designed for a wide range of application, from embedded devices to the enterprise level. The UA server has a highly flexible data model. This allows server developers to structure the server to best fit the application but it requires clients to be able to handle much differently structures servers. Kurt Advosol Inc. The OPC Foundation has adopted the Express Interface as an OPC specification (OPC Xi) and most major OPC vendors will soon support OPC Xi. The main design goal for OPC Xi was to provide a.NET interface with the functionality of OPC DA,AE,HDA.
Xi has a much simpler data model than UA but Xi and UA can be wrapped just as well as UA and DA. An important difference is that Xi is designed for.NET WCF communication while UA is designed for multi-platform use.
Xi is not intended to replace UA. It offers a simple solution to migrate from the troublesome DCOM to.NET. Where does your optimism for UA come from and who are the really committed vendors of UA products for the.NET platform? UA is in the works for over 6 years and the UA Accelerated Adoption group has yet to come up with a solution that hides the UA complexity. UA is designed to support complex data models and multi-platform communication.
There are applications that need these features and these will use UA. For the bulk of applications the classic OPC DA/HDA/AE functionality is sufficient and for these applications Xi provides a simple.NET interface that eliminates DCOM and.NET wrappers. Xi and UA address different needs and are likely going to coexist. Sudhir Chawla 28-Nov-07 18:32 28-Nov-07 18:32 Hi, I am new to OPC technology. I am putting down some points which I know, request you experts to please validate these.
Thanks a lot in advance. Scenario: We need to develop OPC Interface for our client. The OPC Interface don't have to interface with any device, it need to interface with Database to extract data.
The client should be able to view these fields and configure these according to his requirement. My understanding: 1. OPC is written in C to interface with various devices. OPC is meant for PLC / devices only. Can we use the.Net 2.0 API for Server and modify it?
If yes, then can we add interfacing with Database in it? How does OPC client comes to know of the new fields / properties exposed/added at OPC Server?
Which all Server(s) I need to use: AE, DA, DX etc? If we can't modify anything in Server then do we need to write wrappers on top of.Net SERVER API, available from OPCFOUNDATION.ORG to include interfacing with database. Do we need to take membership of OPCFOUNDATION.org to use the API?
Thanks a lot for your help & support. Also request you to please pass any link, which would mention about step by step guide to write OPC Server & OPC Client for testing connection with server. Regards, Sudhir. OPC defines interface specifications that are not restricted to use with PLCs and don’t necessarily have to be implemented in C. Offers.NET client components and server toolkits for the OPC DA (Data Access), OPC AE (Alarms&Event) and OPC HDA (Historical data). Free evaluation versions can be download from. On the web site you find overview descriptions that should answer your questions and details you find in the extensive documentation and many sample applications that are part of the evaluation downloads.
As a member of the OPC Foundation you can download sample implementations of clients and servers. However, you are probably better served when you purchase one of the commercial client component or server toolkit products. K K Manna 23-Mar-04 21:13 23-Mar-04 21:13 We develop solution for process control/SCADA,choosing OPC as an open standard.We developed OPC DA Client using VC(ATL).Now we want to develop OPC DA Server of our own using VC.Lately, most of the debveloper uses a third party toolkits ( eg Softing,Factorysoft,Kepware etc).Does anyone has idea or sample code how to develop a OPC DA Server of our own, without using third party toolkit?A OPC server which will be eqipped with Interfaces to export all the necessary method. K K Manna, (System Engineer), MPG Sdn Bhd, Cyberjaya,Malaysia. OPC specification documents are a good reference point to start with.
Otherwise you can acquire free downloadable kits from Northern Dynamics, Iconics, or similar vendors. Their sample code will help you get started. In case you have any specific queries, feel free to drop a line. Last Visit: 21-Jan-19 7:53 Last Update: 21-Jan-19 7:53 1 General News Suggestion Question Bug Answer Joke Praise Rant Admin Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.