GE Mark VIe System Manual page 103

4.1.4 WorkstationST OPC UA Server
The OPC UA specification combines OPC Data Access (DA), OPC Alarms and Events (AE), and OPC Historical Data
Access (HDA), into one interface. The WorkstationST OPC UA server supports:
• OPC Data Access (DA)
• Historical Alarm and Event access (HDA)
In large systems, there are multiple historians that are logging the same variable at different frequencies. And depending on
the situation, an OPC HDA client will prefer one historian versus another. The HDA server-client is designed to support this
scenario
The following figure illustrates the data flow for an example system around the WorkstationST OPC UA supported functions.
Communication Protocols
WorkstationST OPC UA Server Example
Public Information
GEH-6721_Vol_I_BP System Guide 103