History attributes

<Attribute>.ForceStoragePeriod

The time interval, in milliseconds, at which the value must be stored, even if the value has not changed. A value of 0 disables this feature. As an example, a setting of 3600000 indicates the value must be stored once per hour (measured from the time the object was last put onscan). If this value is less than the scan period of the host object, forced storage occurs every scan period (effectively equivalent to setting a value deadband of 0).

<Attribute>.TrendHi

The default top of the trend scale for clients. This value must be greater than or equal to the low value for the trend. If this value is changed at run time, the maximum engineering unit change is not reflected in the historian until you redeploy the object. This attribute only applies to numeric data types.

<Attribute>.TrendLo

The default bottom of the trend scale for clients. This value must be less than or equal to the high value for the trend. If this value is changed at run time, the minimum engineering unit change is not reflected in the historian until you redeploy the object. This attribute only applies to numeric data types.

<Attribute>.ValueDeadBand

The amount in engineering units by which a value referenced by the attribute must change to force a storage. A value of 0 means it is unused, and thus any value change forces a storage. Also, a quality change in the attribute always forces a storage regardless of this setting. This attribute only applies to numeric data types.