Specifications

15 – Configuring Distributed Server Architecture
346 R400
History, Trends, and Downtime Analysis
Extended Event Archiving
With two exceptions, events for a point are recorded only on the server where
the point is defined. The exceptions are Acknowledgement events and Point
Value Change events, which are recorded both on the server where they occurred
and on the data owner.
Trends
When a trend includes a remote point, historical data for that point is retrieved
from the remote server in real time (see “Configuring Servers to Share Data” on
page 352). If the history intervals on local and remote servers are configured
differently, trends may not display all the requested data. For example, a local
server is configured to collect fast history at 1 second intervals and a remote
server is configured to collect fast history at 5 second intervals. If you create a
trend on the local server requesting data from the remote server at 1 second
intervals, data from the remote server is not displayed in the trend on the local
server.
It is not possible to collect history locally for a remote point. Therefore a remote
point should never be assigned to history.
Downtime Analysis
The Downtime Summary does not show information for remote points.
plscpcg.book Page 346 Monday, May 28, 2001 10:11 AM