Open Platform Communications (OPC) is an interoperability customary for safe information 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 customary was restricted to Microsoft applied sciences, so its software was restricted to Home windows techniques, however the usual is now extra platform-independent, scalable and extensible.
The OPC customary has come to play an important function 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 customary allows techniques to speak extra effectively and successfully, making it doable to gather and analyze info from each a part of the manufacturing course of. This helps to interrupt down information silos, enhance effectivity and responsiveness, and facilitate higher enterprise choices.
Historical past of Open Platform Communications
In 1995, 4 industrial automation distributors launched a process pressure to standardize the data-access protocols throughout their gadgets. On the time, these gadgets predominantly ran Microsoft working techniques. 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 manage manufacturing techniques 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 information acquisition (SCADA) techniques. An HMI is a consumer interface that permits operators to work together with machines and techniques through 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 customary, later dubbed OPC Traditional. Not lengthy after, different {hardware} and software program distributors adopted the brand new customary. This led to the formation of the OPC Basis in 1996 to formalize compliance, certification, interoperability and validation procedures. The inspiration continues to create and keep the OPC specification and guarantee compliance via certification testing.
OPC Traditional specs
The primary model of the OPC customary was primarily based on the Distributed Part Object Mannequin (DCOM), a Microsoft know-how for exchanging information between software program parts throughout a community. Because the title suggests, DCOM is a subset of the Part Object Mannequin (COM), an object-oriented method to creating binary software program parts.
Initially, the OPC acronym stood for OLE for Course of Management as a result of the Object Linking and Embedding (OLE) know-how performed such a key function in Home windows environments and subsequently the OPC customary. OLE is a Microsoft COM desktop know-how for embedding and linking paperwork and different software program objects.
The OPC Basis divides OPC Traditional into three specs:
- OPC Knowledge Entry (OPC DA). First launched in 1996, the specification defines the OPC client-server structure for exchanging information. It particulars how software program can learn and write information, and the information sorts and buildings accessible.
- OPC Alarms and Occasions (OPC AE). First launched in 1999, the specification describes the methods OPC server software program can monitor techniques 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 information collected from gadgets.
In 1998, the OPC Basis started to transform the unique OPC DA specification to net companies. Then, in 2006, the inspiration launched the OPC Unified Structure (OPC UA) specification, the following era of the OPC customary.
OPC Unified Structure specs
In 2006, the OPC Basis launched model 1.0 of OPC UA. The brand new customary was developed partially as a result of Microsoft was transferring away from DCOM towards a service-oriented structure (SOA). SOA is a software program design method that includes reusable companies able to speaking throughout totally different platforms and languages.
On the time, many industries had already included SOA into their manufacturing processes. Distributors additionally needed to broaden their OPC software program to non-Home windows platforms, together with embedded gadgets. The OPC UA customary sought to accommodate these tendencies, whereas nonetheless offering backward compatibility with OPC Traditional.
OPC UA presents an extensible SOA framework designed to help a variety of platforms, from embedded microcontrollers to cloud infrastructure. It goes past OPC Traditional by including a number of essential capabilities:
- Platform independence throughout {hardware} architectures and working techniques.
- Full mapping between the OPC Traditional specs and the brand new OPC UA.
- Larger safety via encryption, authentication and auditing.
- An extensible, multi-layered structure that helps the addition of latest options whereas sustaining backward compatibility with current merchandise.
- An info modeling framework that permits builders to mannequin and prolong advanced multi-level information buildings.
The OPC UA customary, now at model 1.05, consists of 24 core components, which have been printed individually between 2021 and 2023. The OPC Basis additionally offers downloadable COM proxy wrappers for integrating OPC UA and OPC Traditional merchandise.
As of mid-2024, the OPC Basis claimed over 920 member firms 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 firms are Honeywell, IBM, Microsoft, Rockwell, SAP and Siemens.
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