OPCIS points are stored in the Point Service (PNT) and are linked to points in the OPC server using the External ID property on the Point Reference page of the PNT editor. There are two types of OPCIS points:
An OPCIS data point is a point that represents an OPC server data group element. See OPCIS Data Points for more information.
An OPCIS group status point is a point that defines or monitors a property of an OPCIS facility. OPCIS group status points serve several purposes:
An OPCIS group status tag is just like any other tag in the PNT insomuch as it can be configured for alarms, notifications, and history. The properties that make an OPCIS group status tag unique are its facility (the name of the OPCIS group or the OPCIS) and its OPCIS-specific UDC.
An OPCIS has at least one group — the default group. The facility of this group is OPCDEFAULTGROUP. OPCIS group status points can be added for the default group or any custom group.
More:
Assigning an OPCIS Point to an OPCIS Group