Glossary

Callback: see update

COM: Component Object Model

DCOM: Distributed COM

DP: data point

iDP: internal data point

OLE: Object Linking and Embedding

OPC: OLE for Process Control

CALL-R: Control Application Link Layer - Runtime

PA: Peripheral address

DA: Data Access (OPC specifies two DA versions at the moment: DA1.0 and DA 2.0)

ProgID: The program identification. An OPC server is identified in the registry by this ID. The client needs this value, to be able to start the server. This value should be apparent from the OPC server documentation. But it can also be found with the ETM Server Test Tool.

Update: If the OPC server receives a new value from the periphery, it notifies the client of this with a callback

Updaterate: The server notifies the client of value changes at the periphery. For all items in a group, this happens not faster than at the update rate set for the group.