Driver component model

Niagara provides a set of two OPC UA drivers: opcUaClient and opcUaServer. Both follow the Niagara Framework®model for drivers.

The OPC UA specification provides a platform-independent, service-oriented architecture. It integrates all functionality from the existing OPC Classic specification, providing a more secure and scalable solution. The specification is backwards compatible with OPC Classic.

OpcUaServer driver component model

The two main components are the OpcUaServer and OpcUaNamespace. The OpcUaServer component models an OPC UA server instance in the driver framework. There should be only one instance of this driver in a station.

The OpcUaServer component models an Opc UA namespace in the parent OPC UA server. It typically provides a logical grouping of OPC UA variables, histories, and events that can be accessed by an OPC UA client.

OpcUaClient driver component model

The primary OpcUaClient components are:

OpcUaNetwork serves as the parent container for all of OPC UA client devices.
OpcUaDevice represents an OPC UA client.
OpcUaClientPointDeviceExt contains proxy control points used to proxy values to and from the OPC UA server.
OpcUaClientAlarmDeviceExt subscribes the station to alarm events from the OPC UA server.
OpcUaClientHistoryDeviceExt imports histories from the OPC UA server.
OpcUaClientProxyExt is the control point proxy ext used to identify a specific OPC UA server data variable to proxy through this control point.
ImportHistoryExt is the history point extension that imports the history data associated with the specific OPC UA server data variable defined in the proxy ext.

Supported profiles

UA Generic Client Profile
UA Data Access Client Profile
UA History Data Access Client Profile
UA Alarm

Supported facets

The following table lists the OPC UA client facets supported by the Niagara OPC UA drivers. This is a subset of available OPC UA facets.

OPC UA Facet	Description
Base Client Behavior Facet	Defines client behavior for best use by operators and administrators. These behaviors include the ability to configure an endpoint for a server without using the discovery service set; support for manual security configuration and behavior with regard to security issues; support for automatic reconnection to a disconnected server.
Core Client Facet	Defines the core functionality required for any client. This Facet includes the core functions for security and session handling.
AddressSpace Lookup Client Facet	Defines the ability to navigate through the AddressSpace and includes the basic AddressSpace concepts: view and browse, and simple attribute read functionality.
Attribute Read Client Facet	This Facet defines the ability to read Attribute values of Nodes.
DataChange Subscriber Client Facet	This Facet defines the ability to monitor Attribute values for data change.
DataAccess Client Facet	This Facet defines the ability to utilize the DataAccess Information Model, i.e., industrial automation data like analog and discrete data items and their quality of service.
Alarm and Event Client Facet	Partially supported. This Facet defines the ability to subscribe for Event Notifications. This includes basic AddressSpace concept and the browsing of it, adding events and event filters as monitored items and adding subscriptions.
Method Client Facet	This Facet defines the ability to call arbitrary Methods.
Historical Access	This Facet defines the ability to read, process, and update historical data.