Interface startup

On startup, the interface reads site-specific operating parameters such as source and target Data Archive, data update rates, and history recovery settings, from its configuration file. Next, the interface connects to the source and target Data Archives. Each connection to a PI Data Archive is associated with a specific PI user. On the source server, this user must have permission to read PI point attributes and data. On the target server, the user must have read access for point attributes and read and write data access for its points.

Next, the interface builds a list of target PI points, grouping points internally by scan class. Each target point must have a source point. If an invalid point configuration is detected, the point is either rejected or added to the point list and marked as erroneous, and the interface logs the error.

After the interface builds its point lists, it calculates the time offset between Data Archives. Each participating node must be configured with the correct system time for its time zone. During operation, the offset is checked every two minutes. The offset is used for data time stamp adjustments (if enabled) and to time stamp interface status events.

Finally, the server performs history recovery and begins real-time data collection.