UniInt End User
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PI BASemAPI
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- Backup Interface
- Data Source
- Failover ID
GlossaryThe following is a list of the terms used by this manual when discussing UniInt Failover. Active ID PointThe active ID point is located on the data source and identifies which copy of the interface is primary. The primary interface active ID value is set by the /UFO_ID=n startup command-line parameter for the primary interface copy. The value of n must be a positive, non-zero integer. The value of the active ID point is referred to as the ActiveID. Backup InterfaceThe backup interface is used to describe the interface copy which is not the primary interface. Cold FailoverIn a cold failover configuration, the backup interface is not able to load the list of PI tags, but is able to monitor the status of the primary interface. When the primary interface stops collecting data for any reason, the backup interface will load the list of PI tags, start collecting data, and send its data to PI. This configuration will result in a loss of data for the time it takes for the backup interface to load the tag list. Data SourceThe term data source is used as the generic term. The data source refers to the software/hardware where data originates that is to be written to PI. The data source is also the destination of data output from PI. Some examples of data sources are DCSs, PLCs, software systems using APIs, OPC servers, etc. Failover IDIn a failover interface installation, each copy of the interface has its own unique positive integer identifier. This identifier is referred to as the failover ID and is specified with the interface startup parameter, /UFO_ID=n. Failover Update IntervalThe failover update interval determines the rate at which UniInt updates the heartbeat points, how long it takes for the interface to failover, and how much overlapping data may be sent to PI. The optional /UFO_Interval startup parameter specifies the failover update interval for unsolicited failover control tags. Each copy of the interface may define the failover update interval as specified by the /UFO_Interval=i. However, both interface copies participating in failover must use the same value, i, specified by the /UFO_Interval=i parameter. The failover update interval, i, is specified in milli-seconds with the default being 1000 milli-seconds or 1 second. The valid range for the failover update interval is 50 – 20000 milli-seconds. The /UFO_Interval startup parameter can only be used with unsolicited input interface failover control tags. If the interface supports scan based input data and the interface failover tags are defined as scan based input tags, the update interval is then defined by the scan class to which the control tags belong. Download 1.93 Mb. Share with your friends:
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