The OPC 1.0a specification allows
real-time data access. The specification does not support
alarms, event handling, or historical data access. Citect's OPC
Server and OPC Client are compliant to this 1.0a specification, and
can be used respectively with 1.0a compliant OPC Clients and
Servers.
The OPC 2.0 specification is formally referred to as the V2.0
Data Access specification. The additional and optional
specification features of "Alarms & events" and "Historical
data access" can be added. The V2.0 basic specification does
not include these options by default. Citect now has support for
this specification.
See also KB articles Q2536 and Q3392
|