IEC 62541 · Core

Part 7: Profiles

Document number	OPC 10000-7
IEC designation	IEC 62541-7
Colloquially	Part 7
Group	Core

Three levels of granularity

A conformance unit is the atom: one named, testable capability, such as supporting a particular filter or a particular service parameter. A facet is a bundle of conformance units describing a coherent capability - a data-access server, a method-supporting server, a historical raw-data server. A profile is a bundle of facets describing a whole product class, and Standard UA Server Profile (2017) is the one most products aim at. Part 7 defines this machinery; the concrete registry of profiles and facets is maintained separately and is browsable at profiles.opcfoundation.org.

Profile URIs are strings you will actually type

Profiles and facets are identified by URIs, and a server publishes the ones it claims as an array of these strings. Real examples are http://opcfoundation.org/UA-Profile/Server/StandardUA2017, http://opcfoundation.org/UA-Profile/Server/DataAccess, http://opcfoundation.org/UA-Profile/Server/Methods, http://opcfoundation.org/UA-Profile/Server/ReverseConnect and http://opcfoundation.org/UA-Profile/Server/HistoricalRawData2022. Transports have their own: http://opcfoundation.org/UA-Profile/Transport/uatcp-uasc-uabinary and its HTTPS, WebSocket and PubSub siblings. These are identifiers, not addresses to visit.

ServerProfileArray and how claims are tested

ServerProfileArray lives under the Server object's ServerCapabilities and is the server's own statement of what it implements. It is meant to be a client's feature-detection mechanism. It is also the input to conformance testing: the Compliance Test Tool runs the scripts for every conformance unit in every claimed facet, so a claim is a commitment to be tested on. Product certification is performed at an independent test lab against a named profile and facet set, for a specific product version.

Conformance units are the useful unit of argument

Because conformance-unit names are public and stable, they are the right currency for a specification or an acceptance test. Saying the server shall implement the Data Access server facet is testable in a way that shall support OPC UA is not. Each released nodeset also ships a documentation file mapping every standard NodeId to the conformance units it belongs to, which is the least-known and most direct way to find out which units a particular feature falls under.

What it defines

Concept	What it is
Conformance unit	The smallest named testable requirement. Everything above it is a bundle. This is what a test script targets and what an acceptance criterion should cite.
Facet	A coherent bundle of conformance units, such as a data-access or method-support facet. Facets are optional add-ons to a profile.
Profile	A bundle of facets defining a product class. Standard UA Server Profile (2017) is the common target for a general-purpose server.
ServerProfileArray	The array of profile and facet URIs a server claims, under ServerCapabilities. Read it for feature detection; distrust it when it is empty.
Transport profiles	Separate profile URIs per transport and encoding combination, so a server states which transports it supports as claims rather than by implication.
Client profiles	Clients have their own profiles and facets. A client can be certified too, and a client facet is the right way to specify what a data-collection client must handle.
Compliance Test Tool	The official script-driven conformance tester. It runs the units for every facet claimed, producing pass, fail and warning results per unit.
Certification test lab	An independent laboratory that runs conformance, interoperability and robustness testing on a specific product version against named profiles.
Conformance-unit mapping files	Each released nodeset ships a documentation file mapping standard NodeIds to spec sections and conformance units - a practical index from feature to unit.

Do you need to read it?

Anyone writing or evaluating a procurement specification, and anyone preparing a product for certification. Integrators use ServerProfileArray for feature detection. Product teams use facets to scope development, because implementing a facet is a bounded job and implementing OPC UA is not.

Traps that trace back to this part

• Over-claiming ServerProfileArray is a leading cause of failed conformance testing. The test tool exercises every unit in every claimed facet, so a facet advertised optimistically turns into a page of failures. The discipline is to advertise only what is genuinely implemented and tested - even well-maintained reference servers deliberately advertise fewer facets than they implement.
• Under-populated ServerProfileArray is just as common in the field. Plenty of servers ship it empty, stale or holding one generic profile, so a client that gates features on it concludes a capable server cannot do anything. Use it as a hint and fall back to attempting the operation and handling BadServiceUnsupported or BadNotSupported.
• Certification is product-and-version specific, not stack-specific. An example or reference server built with an SDK gets certified; the library itself does not. A vendor stating that they use a certified stack has told you nothing about their own product, and the right question is which product version was certified against which profile.
• A profile name with a year in it is a distinct identifier, not a decoration. StandardUA2017 and the 2022-dated historical facets are separate claims with separate unit sets, so matching a requirement written against one against a server claiming the other needs checking unit by unit.

Last verified 7 September 2026 against OPC UA 1.05.07. The specification parts themselves are published by the OPC Foundation. OPC UA Connect is an educational resource and is not affiliated with the OPC Foundation.