RSView Supervisory Edition Installation Guide

5 • WORKING WITH DISTRIBUTED APPLICATIONS• • • • •Absolute and relative referencesIn a distributed application, use absolute or relative references to refer to applicationcomponents, such as graphic displays, when building RSView commands or connectinggraphic objects to tags.Absolute references point directly at a specific component, by referring to thecomponent’s name and the area (or areas, in the case of nested areas) in which it islocated.For example, an absolute reference to a display called Detail in an area calledAssemblyLineNorth is /AssemblyLineNorth::Detail.5 • PlaceholderAn absolute reference to an application’s root area does not include the application’s name, eventhough the name appears in the root area in RSView Studio.Relative references point at a component relative to the current server or area.For example, a relative reference to a display called Detail is simply the display’s name:Detail. When a relative reference is used, RSView assumes that the component is locatedin the current area.Using absolute and relative referencesAssume the display called Detail, mentioned above, contains an absolute reference to atag called /AssemblyLineNorth::Speed, and a relative reference to a tag called Temp. Therelative reference is simply the tag’s name: Temp.If you copy the Detail display to an area called AssemblyLineSouth, the display will stillrefer to the tag /AssemblyLineNorth::Speed, because it contains an absolute reference tothat tag.However, the display will refer to the tag called Temp in the current area,AssemblyLineSouth, because it contains a relative reference to that tag. If the Temp tagdoes not exist in the AssemblyLineSouth area, an error will appear in the FactoryTalkDiagnostics List when the display is run.Use absolute references when you want to ensure that a specific component is used,regardless of where it is referenced from.Use relative references, for example, when you want to re-use component names in anapplication for a plant that has identical production lines. The application could havemultiple areas, each representing one of the production lines, with the same componentnames in each area. For details about areas, see page 5-3.5-5