Gets/Sets the active state of the Tag class instance
When true
ReadTag, WriteTag, GroupRead and GroupWrite will perform an operation on the tag.
When false
ReadTag, WriteTag, GroupRead and roupWrite will ignore the tag during operation.
When false, the QualityCode and QualityString will equal QUAL_UNCERTAIN and QUAL_STRING_UNCERTAIN respectively. The Now property will operate regardless of the Active state.
Active is useful to suspend specific tag read/write operations within TagGroup classes.