Rockwell Automation FactoryTalk Historian SE 3.0 UniInt Interface User Guide - Manual (Page 85)

UniInt Interface User Manual 79
Historian Tag Value Description
State 2 Tag
Exdesc:
[UFO_STATE:2]
Normally updated by the
Interface on IF-Node2.
May be updated by the
interface on IF-Node1 if
IF-Node2 is unable to
update the tag
Values range between 0
and 5, see description of
State 1 tag.
The failover state tags are optional and do not
require a point on the Data Source. The value
of the state tag can be written to the Data
Source by configuring a normal interface output
tag and setting the SourceTag attribute to the
failover state tag.
Business Network
Process Network
IF-Node1
PI-Interface.exe
/host=PrimaryPI
/UFO_ID=1
/UFO_OTHERID=2
IF-Node2
PI-Interface.exe
/host=SecondaryPI
/UFO_ID=2
/UFO_OTHERID=1
DataSource
DCS/PLC/Data Server
Client
Process Book
DataLink
PrimaryPI
PI Server
Role = 1
SecondaryPI
PI Server
Role = 2
Active ID
Heartbeat 1
Heartbeat 2
Data register 0
.
.
.
Data register n
The redundant solution requires two separate interface nodes communicating with the data
source. The failover scheme requires the creation of six tags on the Historian Server and
three control points on the data source that are specifically used for controlling failover
operation. The Historian tags are necessary to initialize the interface with configuration
information for reading and writing to the control points on the data source. Once the
interface is configured and running, the ability to read or write to the Historian tags is not
required for the proper operation of failover. This leads to a solution that does not require a
connection to the Historian Server after initial startup in order for failover to operate since