QuickOPC for OPC Data Access (OPC-DA)
OPC Data Access (OPC-DA) is the original OPC specification. Its common use it to move real-time data from PLCs, DCSs, and other control devices to HMIs and other display clients, but it gained broader usage scope over the time. The current version of the OPC Data Access specification is 3.0. It leverages earlier versions while improving the browsing capabilities and incorporating XML-DA Schema.
CERN: A brief introduction to OPC Data Access
OPC-DA is fully supported by QuickOPC. You can develop OPC clients with data access capabilities easily with help of QuickOPC components.
In addition to the COM/DCOM based OPC-DA, QuickOPC also supports the SOAP-based OPC XML-DA specification.
Supported OPC-DA Operations
With QuickOPC, you can perform following OPC Data Access operations:
- Discover (browse) OPC servers (applications) on the computer and on the network.
- Browse the address space of the OPC server.
- Read one or more values/items/node attributes.
- Write one or more values/items/node attributes.
- Subscribe to changes of a value/item/node attribute, and possibly later change the parameters of the subscription, or unsubscribe.
- Browse access path for an item.
- Browse OPC properties of an item.
- Get value of one or more OPC properties of an item.
Most developers use the procedural coding model to create their applications. You can also: