0 - AlwaysInAdvise

The Tag is updated if the AllowRead property is set to True

1 - AdviseWhenLinked

The Tag is updated only if the AllowRead property is set to True, and the Tag is associated to an active object, that is, one Display on an open Screen or an enabled Alarm, among others. A Tag link for this purpose can be assigned to the Value, RawValue, Quality, and from Bit00 to Bit31 for Block Element properties, and Quality and TimeStamp for I/O Block properties (default)