Summary:
An OPC Client can browse and add tag items from a single cluster project successfully running on a SCADA machine, however it's not possible with a multi-cluster project.

Solution:
This occurs in SCADA v7.20 (and previous versions). A workaround involves adding a cluster name manually as a prefix to tags in the OPC client (e.g. ClusterName.TagName) to resolve tag communication with SCADA OPC Server.

This problem has been addressed in SCADA v7.30 with new OPC DA server platform. Be aware that this means each tag name needs to be unique to a cluster.

If a v7.30 multi-cluster project has duplicate tag names (attached to different clusters), it would be necessary to define tag names with the cluster name in the format ClusterName.TagName in the OPC client to resolve a tag conflict.

Applies To:
CitectSCADA v7.x
Vijeo Citect v7.x
PowerLogic SCADA v7.x

Keywords: PLS, PLSCADA, PL SCADA, Power SCADA, StruxureWare PowerSCADA Expert, SPE, PSE, 7.1, 7.2, 7.10, 7.20, multiple clusters, Q6401