OPC, standards for the IIoT
Making data actionable by moving it away from machines and onto software is a fundamental challenge for the industrial “internet of things.” Looking to tackle that challenge is the object linking and embedding for process control standard, which is a series of software interface standards and specifications created to allow Windows programs to communicate with industrial hardware devices.
The standards, which were created by industry vendors, end-users and software developers, define the interface between clients and servers, and servers and servers, including access to real-time data, historical data, monitoring of alarms and events and other applications, according to the OPC Foundation.
OPC was first released in 1996, to abstract power line communication specific protocols (Modbus, Profibus, etc.) into a standardized interface, allowing human-machine interface/supervisory control and data acquisition systems to convert generic OPC requests into device-specific requests.The standard was originally restricted to the Windows operating system, and is very similar to component object model since OLE was based on the Windows COM standard.
Challenges before OPC
According to MatrikonOPC, some of the challenges companies face with sharing data from machines, include proprietary protocols; custom drivers; complex integration; device and controller loading; obsolescence of legacy infrastructure; and enterprise-wide data connectivity
Connectivity configurations
According to OPC DataHub, a typical OPC-connected situation involves a single server-client connection on a single computer. Other possibilities include OPC aggregation, which connects an OPC client to several OPC servers; OPC tunneling, which connects an OPC client to an OPC server over a network; and OPC bridging, which connects an OPC server to another OPC server to share data.
Benefits of the IIoT standard
Because OPC is an open standard, manufacturers can take advantage of potentially lower costs and users are given more options. Manufacturers only need to provide a single OPC server for their devices to communicate with any OPC client, according to OPC DataHub. Software vendors include OPC client capabilities in their products so they become compatible with thousands of hardware devices.
Following are some key benefits of using OPC as outlined by MatrikonOPC:
- An OPC enabled application can freely communicate with any OPC-enabled data source visible to it on the network without the need for any driver software.
- OPC-enabled applications can communicate with as many OPC-enabled data sources as they need.
- OPC is common and there exists an OPC connector available for nearly every modern and legacy device on the market.
- OPC-enabled data sources may be swapped out, exchanged or upgraded without the need to update the drivers used by each application (data sink) communicating with the data source via OPC.
- Users are free to choose the best suited devices, controllers and applications for their projects without worrying about which vendor each came from and whether they will communicate with each other.
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