tagdictionary-DataPolicy

Starting in Niagara 4.1, tag dictionaries may include data policies. A data policy provides additional metadata associated with a tag or tag group.  The tagdictionary palette contains the following DataPolicy components:
  • DataPolicy
  • BooleanDataPolicy
  • EnumDataPolicy
  • NumericDataPolicy
  • StringDataPolicy
 NOTE: Typical tagging operations do not require data policies. The data policy functionality is provided primarily for use by the Niagara 4.1 Analytics engine. For that reason, tag dictionaries may include added data policies. 

An Add Data Policy action has been added to TagInfo and TagGroupInfo components.  Invoking this action prompts you to select a DataPolicy type to add to the selected TagInfo or TagGroupInfo component in a tag dictionary.  

You can also add a data policy to TagInfo or TagGroupInfo components by dragging a DataPolicy component from the tagdictionary palette and dropping it on the desired TagInfo or TagGroupInfo component.

 NOTE: Only a single data policy can be added to TagInfo or TagGroupInfo components. You may not add a data policy if the TagInfo component is a Marker tag, or if the TagInfo or TagGroupInfo component already has a DataPolicy child.  

Properties for Data Policy

Name Value Description
Min Interval drop-down with time intervals The minimum allowed interval when requesting a trend.
Max Interval drop-down with time intervals The maximum allowed interval when requesting a trend.
Preferred Time Range three fields: drop-down list for time period, drop-down list for day of the month, drop-down list for time selector The default time range of the data when a request does not include a time range.
Preferred Rollup drop-down list of arithmetic functions The default rollup of the data when a request does not specify the rollup function.
Preferred Aggregation drop-down list of arithmetic functions The default aggregation when a request does not specify the aggregation function.
Units drop-down list of units of measure Defines the unit of measure for the data gathered from each point.
Precision 32 bit (default), 64 bit Allows you to select 32 bit or 64 bit options for the history data logging. The 64 bit option allows for higher level of precision but consumes more memory.
Totalized    
Trend Required true (default) or false When true, all points must have a trend.
Units drop-down list of units of measure Defines the unit of measure for the data gathered from each point.