Deviation
- Last UpdatedMar 10, 2025
- 2 minute read
Contains one row for each defined deviation for an analog tag. The deviation is the percentage of change in a tag's value from a fixed value, called the target. Each analog tag can have two defined deviations: major and minor. This table is populated when an InTouch application is imported and is not used by the AVEVA Historian.
|
Column |
Data Type |
Description |
|---|---|---|
|
(PK) (FK) TagName |
TagNameType |
The unique name of the tag within the AVEVA Historian system. TagName is a foreign key from the Tag table. |
|
(PK) (FK) ContextKey |
int NOT NULL |
The unique numerical identifier for the context. ContextKey is a foreign key from the Context table. |
|
MinorDeviation |
real NULL |
The percentage that the tag can deviate from the target value before a minor deviation alarm condition is produced. |
|
MinorChecked |
bit NOT NULL |
Used to determine the alarm state of the tag based on the minor deviation. 0 = Not in an alarm condition; 1 = In an alarm condition. |
|
MinorPriority |
int NULL |
The priority level for the minor deviation. Valid values are numbers between 1 and 999, with 1 being the highest priority and 999 being the lowest priority. |
|
MajorDeviation |
real NULL |
The percentage that the tag can deviate from the target value before a major deviation alarm condition is produced. |
|
MajorChecked |
bit NOT NULL |
Used to determine the alarm state of the tag based on the major deviation. 0 = Not in an alarm condition; 1 = In an alarm condition. |
|
MajorPriority |
int NULL |
The priority level for the major deviation. Valid values are numbers between 1 and 999, with 1 being the highest priority and 999 being the lowest priority. |
|
Target |
float NULL |
The reference value of the tag from which minor and/or major deviation percentages are based. |
|
Deadband |
real NULL |
The deviation percentage the tag value must drop below the target before the tag is taken out of alarm. |