Rockwell Automation FactoryTalk Historian SE 3.0 H2H Interface User Guide - Manual (Page 27)

FactoryTalk Historian To Historian Interface User Guide 21
Failover Status
When configured for server-level failover users can specify a status tag. The interface will
update this tag to indicate whether the primary or secondary source server is active. It will
also update this tag when it is in the process of failing over (no active source) or experiencing
network communication errors.
Deployment Scenarios
There are two typical FactoryTalk Historian to Historian interface applications. One is to
isolate users from the source Historian Server. This may be for security requirements, load
distribution, database centralization or to resolve remote access issues. In this scenario users
will want to configure the interface for exception data collection to provide real-time updates
to end users.
The other application is to maintain a copy of archive data on a secondary Historian Server.
For example, in this scenario the receiving Historian Server maybe a backup of the source
Historian Server. This is achieved by running the interface in archive data collection mode
with tag attribute overrides in the startup configuration file. The tag attribute overrides enable
users to configure interface data collection without configuring receiving tags specifically for
PItoPI. This strategy allows receiving tags to be configured for their native interfaces and
eliminates the need for mass tag editing prior to bringing the backup server online, reducing
down time.
Historian to Historian within a Historian Collective
PItoPI can be used to distribute data within a collective. The primary method for data
distribution within a collective is n-way data buffering from the data source. N-way data
buffering provides the best performance and is the most efficient method for data distribution.
However due to system architecture and security restrictions this may not always be possible.