• Redundant DI Objects

• Application Engines can host Redundant Device Integration Objects (DI Objects). The RedundantDIObject monitors and controls the redundant DIObject data sources. Unlike redundant AppEngines, individual DIObject data sources do not have redundancy-related states. For all intents and purposes, they function as standalone objects.
• Only one DIObject data source provides field device data through the RedundantDIObject at a time. Both data sources must have commonly configured DAGroups which are reflected in and channeled through the RedundantDIObject, which monitors the two DIObject data sources and determines which one is Active at any given time. Both data sources must also have the same item address space.
• The Redundant DI Object is a DINetwork Object used to enable continuity of I/O information from field devices. The Redundant DI Object provides the ability to configure a single object with connections to two different data sources. If the primary data source fails, the Redundant DI Object automatically switches to the backup data source for its information. There is a one-to-two relationship between an instance of the Redundant DI Object and the running instances of the source DI objects; that is, for each Redundant DI Object, a pair of source DI Objects is deployed.

• Configuration RedundantDIObjects

• Configure redundancy in data acquisition objects in the ArchestrA IDE through their editors. Data acquisition redundancy objects (two DIObjects and the RedundantDIObject) do not have redundancy-related deployment statuses.
• In data acquisition redundancy, you must configure all three components: a Primary DIObject data source, a Backup one, and a Redundant DIObject.
• Because data acquisition redundant components are essentially standalone objects, all valid operations that apply to any other ApplicationObjects apply to the three objects. All ArchestrA IDE commands, Galaxy Dump and Load functions, and import and export operations are valid on the two DIObject data sources and the RedundantDIObject.

• The main focus of RedundantDIObject configuration is:

• Setting the Primary DI Source and Backup DI Source on the General tab of the object’s editor.

• Setting up the common scan groups, and block read and block write groups on the respective tabs of the object’s editor.

• Deployment

• Deployment for data acquisition redundancy is the same as individually deploying unrelated objects. No special conditions apply to each DIObject data source and the RedundantDIObject.

• What Happens in Run-time

• During run-time, the RedundantDIObject monitors the status of the DIObject data sources, and handles the switching from Active to Standby object when failure conditions arise.