Some of the applications you may create will consist of large numbers of tags. There may be circumstances under which you may wish to prevent certain groups of tags from loading at startup to reduce the amount of memory required to run the application, or you might require that only certain groups of tags are loaded on specific workstations. You can use this functionality to ensure that you do not exceed the maximum number of tags permitted for your VTS application due to licensing restrictions (please refer to Tag Licensing). In such situations, VTS makes it possible to disable some tags, preventing them from loading and consuming unnecessary amounts of memory. This process is referred to a tag area filtering.
Further, for some applications you may wish to filter alarm tags so that specific alarms load on specific workstations. The typical purpose for this functionality is when you have a remote application installation that has one common configuration for all workstations, but on some machines you wish to see a subset of the alarms (for example, if you wished to restrict alarms to specific geographical areas). This process of alarm area filtering restricts the alarm displays and sounds to only those areas that have been enabled for the relevant machine.
For both tag area filtering and alarm area filtering, the area that is being filtered is the normal Area property of the tag.
Information on tag area filtering can be found in the VTS Programmer's Guide: Config.ini [AREAS] Section Variables, while information on alarm area filtering is included in the VTS Programmer's Guide: Workstation.ini Alarm Area Filtering.