Open Platform Communications (OPC) is an interoperability commonplace for safe knowledge alternate in industrial automation and different areas. It’s designed to be platform-independent so gadgets from totally different distributors can alternate info. The unique commonplace was restricted to Microsoft applied sciences, so its utility was restricted to Home windows methods, however the usual is now extra platform-independent, scalable and extensible.
The OPC commonplace has come to play a significant position in Trade 4.0, a motion towards sensible manufacturing that embraces digital transformation and cutting-edge applied sciences, together with synthetic intelligence (AI) and industrial web of issues (IIoT).
Trade 4.0 represents the fourth industrial revolution, which emphasizes communication and interoperability.
The OPC commonplace allows methods to speak extra effectively and successfully, making it attainable to gather and analyze info from each a part of the manufacturing course of. This helps to interrupt down knowledge silos, enhance effectivity and responsiveness, and facilitate higher enterprise choices.
Historical past of Open Platform Communications
In 1995, 4 industrial automation distributors launched a activity pressure to standardize the data-access protocols throughout their gadgets. On the time, these gadgets predominantly ran Microsoft working methods. The duty pressure devised a plan to summary the communication protocols utilized in programmable logical controllers (PLCs), that are small, special-purpose computer systems extensively deployed in industrial environments to regulate manufacturing methods and processes.
The preliminary specification abstracted the protocols right into a standardized interface that converts learn/write requests between human-machine interface (HMI) and supervisory management and knowledge acquisition (SCADA) methods. An HMI is a person interface that permits operators to work together with machines and methods by way of a PLC, and SCADA is a well-liked pc structure generally used for industrial course of management. The OPC interface converts device-specific requests into generic OPC requests and converts generic OPC requests into device-specific requests.
In 1996, the duty pressure launched model 1.0 of the OPC commonplace, later dubbed OPC Basic. Not lengthy after, different {hardware} and software program distributors adopted the brand new commonplace. This led to the formation of the OPC Basis in 1996 to formalize compliance, certification, interoperability and validation procedures. The muse continues to create and keep the OPC specification and guarantee compliance by means of certification testing.
OPC Basic specs
The primary model of the OPC commonplace was primarily based on the Distributed Part Object Mannequin (DCOM), a Microsoft expertise for exchanging knowledge between software program elements throughout a community. Because the title suggests, DCOM is a subset of the Part Object Mannequin (COM), an object-oriented strategy to creating binary software program elements.
Initially, the OPC acronym stood for OLE for Course of Management as a result of the Object Linking and Embedding (OLE) expertise performed such a key position in Home windows environments and subsequently the OPC commonplace. OLE is a Microsoft COM desktop expertise for embedding and linking paperwork and different software program objects.
The OPC Basis divides OPC Basic into three specs:
- OPC Knowledge Entry (OPC DA). First launched in 1996, the specification defines the OPC client-server structure for exchanging knowledge. It particulars how software program can learn and write knowledge, and the information varieties and buildings out there.
- OPC Alarms and Occasions (OPC AE). First launched in 1999, the specification describes the methods OPC server software program can monitor methods and ship alarms to shopper software program.
- OPC Historic Knowledge Entry (OPC HDA). First launched in 2001, the specification defines the queries and analytics that may be utilized to the historic time-stamped knowledge collected from gadgets.
In 1998, the OPC Basis started to transform the unique OPC DA specification to internet companies. Then, in 2006, the inspiration launched the OPC Unified Structure (OPC UA) specification, the following era of the OPC commonplace.
OPC Unified Structure specs
In 2006, the OPC Basis launched model 1.0 of OPC UA. The brand new commonplace was developed partly as a result of Microsoft was transferring away from DCOM towards a service-oriented structure (SOA). SOA is a software program design strategy that includes reusable companies able to speaking throughout totally different platforms and languages.
On the time, many industries had already integrated SOA into their manufacturing processes. Distributors additionally needed to develop their OPC software program to non-Home windows platforms, together with embedded gadgets. The OPC UA commonplace sought to accommodate these traits, whereas nonetheless offering backward compatibility with OPC Basic.
OPC UA affords an extensible SOA framework designed to assist a variety of platforms, from embedded microcontrollers to cloud infrastructure. It goes past OPC Basic by including a number of necessary capabilities:
- Platform independence throughout {hardware} architectures and working methods.
- Full mapping between the OPC Basic specs and the brand new OPC UA.
- Better safety by means of encryption, authentication and auditing.
- An extensible, multi-layered structure that helps the addition of recent options whereas sustaining backward compatibility with present merchandise.
- An info modeling framework that permits builders to mannequin and prolong complicated multi-level knowledge buildings.
The OPC UA commonplace, now at model 1.05, consists of 24 core elements, which have been revealed individually between 2021 and 2023. The OPC Basis additionally gives downloadable COM proxy wrappers for integrating OPC UA and OPC Basic merchandise.
As of mid-2024, the OPC Basis claimed over 920 member corporations and hundreds of OPC-compliant merchandise. Members embrace leaders within the software program, {hardware}, industrial automation, machine-to-machine (M2M), sensible vitality, and discrete- and process-manufacturing sectors. Among the many most well-known corporations are Honeywell, IBM, Microsoft, Rockwell, SAP and Siemens.
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