Connectivity Framework Annex B : Assessment Template : OPC-UA
B . 6.3 Usage Viewpoint
B . 6.3.1 Architecture ( Section 6.3.1 )
B . 6.3.2 Technology
Options ( Section 6.3.2 )
B . 6.3.3 Applications ( Section 6.3.3 )
B . 6.3.4 Typical
Usage ( Section 2.2 )
B . 6.3.5 Operations ( Section 2.3.8 )
B . 6.3.6 Security ( Section 2.3.5 )
B . 6.3.7 Safety ( Section 2.3.9 )
B . 6.3.8 Gateways ( Section 3.3 )
Summarize the main concepts , and high-level architecture , and terminology . Describe the end-to-end information exchange path .
OPC-UA consists of multiple OPC-UA-Clients connected to a OPC-UA-Server . A OPC-UA- Server holds an address space , which is a collection of data objects organized in a linked graph .
Requests originate at a OPC-UA-Client and are sent to an OPC-Server ; the OPC-Server processes the request , and sends a reply back to the OPC-UA-Client . Requests are addressed to a specific data object in the server ’ s address space . Structured data is used for the request and reply .
A OPC-UA specification for publish and subscribe architectures is currently under development . List the choices to be made for using the connectivity technology in a system .
• Selection of SDK used to implement OPC-UA clients and servers supporting the desired variants ( OPC-UA profiles ).
• Selection of the underlying transport : OPC-UA Binary / TCP or XML / HTTP .
A general statement of the typical applications that rely on this connectivity technology and the reason for using the connectivity technology .
Industrial automation and process control applications . Client-server interactions between components such as devices or applications . Expose the address space of systems and devices to facilitate configuration , browsing and data access . What function or where in the system this technology is typically used ? OPC-UA is deployed on devices to allow device configuration and data-access .
For existing brown field installations , OPC-UA is typically deployed at system boundaries to expose the system address space , support browsing , configuration , monitoring and service invocation . Newer devices and systems are building in OPC-UA . Can one monitor , manage , and dynamically replace elements of the connectivity function ? OPC-UA discovery services are defined to allow dynamic discovery of components . What are the system security implications of this connectivity technology ?
Security is provided at the transport level between each client and server . Clients are authenticated via name and password , PKI certificate , of WS-Security Tokens .
Each server enforces access control . Servers may support fine-grained access control to individual variable and operations . For systems that need it , are certifiable implementations available ?
There are currently no safety-certified OPC-UA implementations .
List of gateways to core connectivity standards and other relevant connectivity technologies .
• An OPCUA-DDS gateway standard is under development by the OMG .
• An OPC-UA DDS profile is under development by the OPC Foundation .
• An OPC-UA gateway standard is under development by oneM2M
• OPC-UA clients can connect to OPC-UA servers via HTTP .
There are commercially-available gateways between OPC-UA and many industrial protocols such as Modbus , Profibus , Foundation fieldbus , etc .
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