Specialized Client Objects
A specialized client object builds provides functionality that is relevant for specific problem domain. It contains, in a sense, pre-packaged pieces of reusable code that the developer would typically need to write, whenever he needs to develop a solution for that problem domain.
In OPC Unified Architecture (OPC UA), the problem domain addressed by the specialized client object is often a selected part of the OPC UA specification.
QuickOPC exposes several useful specialized client objects to you, saving you from having to write unnecessary parts of code.
OPC UA Global Discovery Client
The OPC UA Global Discovery Client is a specialized OPC UA client object for global discovery. In the OPC UA specifications, the functionality covered by this type is described in Part 12: Discovery and Global Services, in the Global Discovery Server section.
The methods allow querying for applications and/or servers, and registering, unregistering or updating application registrations in the GDS.
OPC UA Certificate Management Client
The OPC UA Certificate Management Client is a specialized OPC UA client object providing access to certificate management (CM) information model of an OPC UA Global Discovery Server (GDS).
The methods allow getting certificate groups, requesting key pairs or certificate signing and obtaining the results, retrieving trust lists, and more.
OPC UA Client Application Service
The OPC UA Client Application Service is capable of maintaining client application registrations with one or more GDS servers simultaneously. It keeps track of the registrations (and unregistrations) performed. You can use this service to easily register your application with the GDS, and manage its certificates and trust lists.
This service works on even higher level than the specialized client objects - OPC UA Global Discovery Client and OPC UA Certificate Management Client. Instead of having to call the OPC UA methods as described in the specification, the client application service already puts together the necessary parameters, decides which method to call when, and then performs several operations at once. It also communicates directly with the application environment - it stores the certificate obtained from the GDS into the certificate store, refreshes trust lists, etc.
Footnote & required disclosure: QuickOPC (including its Options) is a software development kit (SDK) for development of OPC clients. Installing QuickOPC or its Options does not change system settings.