Quod erat demonstrandum: The OPC UA interface standard
Standard of the future: The “Open Platform Communications Unified Architecture”, or OPC UA, is increasingly gaining acceptance in mechanical and plant engineering. This open interface enables digital networking, runs on numerous operating systems, and ensures manufacturer-independent compatibility. Learn more with the OPC UA Demonstrator by VDMA R+A.
The OPC UA Demonstrator is a new future-oriented approach by VDMA Robotics + Automation for standardized and manufacturer-independent data exchange. This communication standard extends across multiple levels of the automation pyramid and puts an end to strictly hierarchical data flow. In other words: It is an enabler of digital networking in production.
Open communication standards are vital for the production of the future. OPC UA enables standardized collaboration between different machines and systems regardless of platform or manufacturer. A video which explains what the VDMA OPC UA Companion Specifications are all about will be released soon.
Preparing production facilities for the future.
What has been common in offices for a long time—thanks to network interfaces and USB connectors—will now become a reality in production as well. “Plug & work” enables conversion of production facilities according to changing requirements—regardless of which machine or component was supplied by which manufacturer. Apart from condition monitoring and predictive maintenance, OPC UA also enables general production optimization through standardized on-hand information.
However, the devil is in the details: Even if all machines and systems use OPC UA, they still cannot completely “understand” each other. The precondition for flawless communication is a standardized communication medium (e.g. wired or cell phone) as well as a definition of the format and the meaning of information (semantics). To be more specific: There must be a definition on how information—be it measured values, alarms or conditions—is interpreted, i.e. which data format and what unit is used. Here, it is up to the manufacturers organized in the VDMA to agree on so-called companion specifications.
Greater efficiency, greater flexibility, greater competitive edge.
VDMA Robotics + Automation with its more than 280 members is one of the first industry associations worldwide to work on such a OPC UA companion specification that will cover large parts of the automation industry. The goal: Paving the way for more efficient and transparent production processes to enable even more flexible, fast, and customized implementations of customer specifications.
One Demonstrator—two use cases
The OPC UA Demonstrator at automatica 2018 integrates use case control and condition monitoring, making OPC UA’s potential tangible. Rather than presenting an abstract concept, the displayed system is a physical, fully automated unit that assembles fidget spinners. Here, interested visitors can order products with a custom design, which will then be produced live and on the spot.
More than 20 component manufacturers, system integrators and software specialists joined hands for this project to integrate a rotary indexing table, axes and grippers, machine vision systems and robots. Condition monitoring is cloud-based and independent from the manufacturer or type of robot. All relevant condition data can be monitored in real time on a dashboard.
OPC UA approaches by VDMA R+A departments
The first step is to define a motion device system, e.g. through measured values, condition information, and properties of robot axes. The goal: Standardized and manufacturer-independent provision of condition data and device information to superimposed IT systems such as MES, Line PLC and the cloud. The second step comprises configuration and parameter setting via OPC UA.
The first part of the companion specification controls the machine vision system. This requires synchronization of a machine vision system’s activities with the mechanics of the machine or installation. For this purpose, a capability-based modeling approach was selected to derive the system’s behavior using a state machine, hence controlling the machine vision system using method calls.
Integrated assembly solutions:
These solutions are based on a generic approach using skills. All components such as grippers, linear axes and swiveling units can be defined independently from manufacturers and resources using standardized skills. Here, many assembly and handling tasks use a combination of skills. These combinations enable users to orchestrate the entire process of any given machine. Skills are defined and called using OPC UA methods.
Benefits of the project
Significant cost and time savings: A standardized interface instead of various proprietary interfaces provides superior quality and reduces efforts in development, personnel and commissioning—in terms of both time and costs.
Optimized interoperability: OPC UA is a standardized language that facilitates direct communication and data transmission between installations, machines and components, eliminating the need for a gateway that translates the information.
Increased flexibility: Control sequences can be modified and component exchange becomes easier, regardless of the manufacturer.
Guaranteed reusability: Thanks to the standardized description, products can be modeled through software, enabling their use with other standardized interfaces.
More innovative energy: The definition of a standard used across manufacturers causes the industry to grow even closer, which is a prerequisite for synergies and product improvements.