Sometimes, a list of supported services is used to compare SDKs, libraries or toolkits. For this reason, we provide the list of OPC UA services OPC Data Client supports, here. It should be noted, however, that comparison of supported services should not be done blindly. Always take following concerns into consideration:
- The number of services is intentionally kept low in OPC UA. The distinguishing factors lie deeper - in the various arguments that these services accept. Many services provide very rich functionality depending on the arguments they are passed, and the fact that a particular service is supported does not tell much by itself, without further qualification. You need to compare the actual capabilities of the toolkits, as seen from the user's perspective, instead.
- Many toolkits provide very thin layer over the OPC UA service calls, and that's all they do. They then leave it onto you to assemble the arguments, then call the services in the proper way and sequence, and interpret the results. That's easy for the toolkit author, but does not give you any added value. And, it's easy, but kind of useless, to expose many OPC UA services in this way, if all the toolkit does is to make it possible to invoke them. OPC Data Client has a very different approach. The individual OPC UA service are not exposed to you directly. Instead, you are given high level, task-oriented methods, that in turn call the necessary OPC UA services internally - sometimes, many of them for one OPC Data Client API method.
The OPC UA services that OPC Data Client supports are listed below.
Discovery Service Set
- FindServers
- FindServersOnNetwork
- GetEndpoints
SecureChannel Service Set
- OpenSecureChannel
- CloseSecureChannel
Session Service Set
- CreateSession
- ActivateSession
- CloseSession
NodeManagement Service Set
- RegisterNodes
- UnregisterNodes
View Service Set
- Browse
- BrowseNext
- TranslateBrowsePathsToNodeIds
- RegisterNodes
- UnregisterNodes
Query Service Set
(none)
Attribute Service Set
Method Service Set
MonitoredItem Service Set
- CreateMonitoredItems
- ModifyMonitoredItems
- DeleteMonitoredItems
Subscription Service Set
- CreateSubscription
- Publish
- Republish
- DeleteSubscriptions
See Also
