Network Monitoring using OPC - (OLE) for Process Control Project Advisor : Dr. Chung-E-Wang Prepared By: Bhumi Patel

Topics  OPC Introduction  OPC Advantages  OPC Standards  OPC DA and OPC XML DA  OPC XML DA Service Types  Polled Subscription Interaction  OPC XML DA Disadvantages  Technology  Network Monitoring  Future Enhancement

What is OPC?  OPC is a software interface standard that allows Windows programs to communicate with industrial hardware devices.  It was originally created in 1996 to specify standards for the communication of real-time plant data between control devices from different manufacturers.  OPC is heavily used within the process industries and discrete manufacturing.

OPC Origin  Traditionally, any time a package needed access to data from a device, a custom interface, or driver, had to be written.

OPC Origin (Continued)  There were many problems associated with custom driver based communications; some of these most common ones were:  High cost  Proprietary technology that tied users to a particular vendor  Hard to configure  Maintain - because each custom driver had its own way of doing things  Hard to keep up-to-date because of the constant release of new devices and applications

OPC Origin (Continued)  The purpose of OPC is to define a common interface that is written once and then reused by any business, SCADA, HMI, or custom software packages.

OPC Advantages  OPC is an open standard, which means lower costs for manufacturers and more options for users.  Hardware manufacturers need only provide a single OPC server for their devices to communicate with any OPC client.  Software vendors simply include OPC client capabilities in their products and they become compatible with thousands of hardware devices.  Users can choose any OPC client software they need, resting assured that it will communicate seamlessly with their OPC-enabled hardware, and vice-versa.

OPC Standards  OPC Data Access (OPC DA)  OPC Alarms & Events  OPC Batch  OPC Data eXchange  OPC Historical Data Access  OPC Security  OPC XML-DA  OPC Complex Data  OPC Commands

OPC Data Access (DA)  OPC Data Access was the first OPC specification.  It is a group of standards that provides specifications for communicating real-time data from data acquisition devices like PLCs.  It was based on COM/DCOM protocol. Problem:  It is based on Microsoft Platform, and is not portable to other operating systems  DCOM timeouts

OPC XML DA  It is the first web service or SOAP (Simple Object Access Protocol) based protocol known as XML-DA specification.  It allows access to process data from operating systems other than Microsoft in a standardized way.

OPC XML DA – Service Types  Status – Mechanism for checking server status  Read – Provides ability to read item values and quality  Write – Writes values for one or more items  Subscription – Used to initiate a subscription contract with a server  Subscription Polled Refresh – Periodically acquire the latest item values  Subscription Cancel – Terminate subscription  Browse – Browse available items on server  Get Properties – Get server properties

Polled Subscription Interaction

OPC XML DA Disadvantages  Not suitable for transferring large data  XML is slower than COM  OPC XML DA is a stateless service

Network Monitoring  The application will monitor following network variables using OPC XML DA: o Upload Speed o Download Speed o Sent Packets o Received Packets  Server o Windows Communication Foundation (WCF) using C#.NET 4.0  Client o ASP.NET 4.0 with C#.NET 4.0

References    access-versions.aspx  Integrated IEDs With OPC Technology by Pankaj Bhatt and Roger P. Baldevia 

Questions? Thank you… !!