Open Platform Communications

-
Open Platform Communications (OPC) is a series of standards and specifications for industrial telecommunication. An industrial automation industry task force developed the original standard in 1996 under the name OLE for Process Control (Object Linking and Embedding for Process Control). OPC specifies the communication of real-time plant data between control devices from different manufacturers.
After the initial release in 1996, the OPC Foundation was created to maintain the standard. As OPC has been adopted beyond the field of process control, the OPC Foundationchanged the name to Open Platform Communications in 2011. The change in name reflects the applications of OPC technology for applications in process control, discrete manufacturing, building automation, and many others. OPC has also grown beyond its original OLE (Object Linking and Embedding) implementation to include other data transportation technologies including XML, Microsoft's .NET Framework, and even the OPC Foundation's binary-encoded TCP format.

Design

OPC was designed to provide a common bridge for Windows based software applications and process control hardware. Standards define consistent methods of accessing field data from plant floor devices. This method remains the same regardless of the type and source of data. An OPC Server for one hardware device provides the same methods for an OPC Client to access its data as any and every other OPC Server for that same and any other hardware device. The aim was to reduce the amount of duplicated effort required from hardware manufacturers and their software partners, and from the SCADA and other HMI producers in order to interface the two. Once a hardware manufacturer had developed their OPC Server for the new hardware device their work was done to allow any 'top end' to access their device, and once the SCADA producer had developed their OPC Client their work was done to allow access to any hardware, existing or yet to be created, with an OPC compliant server.
OPC servers provide a method for many different software packages (so long as it is an OPC Client) to access data from a process control device, such as a PLC or DCS. Traditionally, any time a package needed access to data from a device, a custom interface, or driver, had to be written. 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.
There is nothing in the OPC specifications to restrict the server to providing access to a process control device. OPC Servers can be written for anything from getting the internal temperature of a microprocessor to the current temperature in Monument Valley.
Once an OPC Server is written for a particular device, it can be reused by any application that is able to act as an OPC client. OPC servers use Microsoft’s OLE technology (also known as the Component Object Model, or COM) to communicate with clients. COM technology permits a standard for real-time information exchange between software applications and process hardware to be defined.
It is important to note that some OPC specifications are published, others are available only to member of the OPC Foundation. So whilst no company "owns" OPC and anyone can develop an OPC server, whether or not they are a member of the OPC Foundation, non-members will not necessarily be using the latest specifications. Anyone can integrate OPC products, and there is no pre-requisite for the system integrator to belong to any organization. It is therefore up to each company that requires OPC products to ensure that their products are certified and that their system integrators have the necessary training.

Comments

Post a Comment

Popular posts from this blog

PROFIBUS

-
Image
 PROFIBUS PROFIBUS or Process Field Bus was introduced in 1989 and it is sometimes confused with PROFINET. It links plant automation modules with the process control. PROFIBUS uses a multi drop single cable to connect the devices. This method is cost effective especially for larger sites when compared to old methods. Its installation cost is low and it is easy to find faults as well because it is a single cable. Types of PROFIBUS There are two types or versions of PROFIBUS commonly known as 1.    PROFIBUS DP 2.    PROFIBUS PA Here is a brief introduction to both of these types. PROFIBUS DP It runs over two core screened cable that is violet sheathed and its speed varies from 9.6Kbps to 12Mbps. A particular speed can be chosen for a network to give enough time for communication with all the devices present in the network. If systems change slowly then lower communication speed is suitable and if the systems change quickly then effective communication will happen through
Read more

Industrial Safety Systems

-
Image
The Industrial Safety Systems and Their Types Industrial automation has minimized the human interaction with the machines but has not completely eliminated it. Industrial safety systems are introduced to protect the human who work in hazardous plants. Some examples of these are oil and gas, chemical and nuclear plants. The industrial safety systems not only protect the humans but also protect the environment and the plant itself from the chemical reactions. These systems do not control any process but in fact come into play when it is not possible to control a process through normal means. They are rather installed as a protective measure and are quickly becoming the need of every working environment. There are various types of safety systems in place and their use depends on the type of industry they are used in. Here is a look at some of them. Process Control Systems (PCS) They are installed for the monitoring of the manufacturing environment and they control the manufact
Read more

Wireless Field Instrumentation

-
Image
Large-scale, reliable, next-generation plant-wide field wireless system A new architecture for our “Grow” concept Yokogawa launched the world’s first wireless field products conforming to the ISA100.11a standard in 2010 and has led the business ever since. Now, Yokogawa has released a new, large-scale, reliable, next-generation plant-wide field wireless system. In developing this system, which forms the core of field digital solutions, Yokogawa has focused on the following three key features. 1. Reliability: reliable high-performance field wireless and redundant technologies 2. Flexibility: flexible architecture that supports the full range, from small to large-scale plants 3. Openness: open ISA100.11a standard that allows third-party field wireless devices to be connected This new system has been developed in line with Yokogawa’s “Grow” concept of helping customers to grow and enabling ourselves to evolve and continue to offer timely solutions.  →The individual spec
Read more