The DataChangeTrigger is an enumeration that specifies the conditions under which a data change notification should be reported. The possible values are described in Table 134.
Table 134– DataChangeTrigger values
|
Name |
Value |
Description |
|
STATUS |
0 |
Report a notification ONLY if the StatusCodeassociated with the value changes. See Table 183for StatusCodesdefined in this document. OPC 10000-8specifies additional StatusCodesthat are valid in particular for device data. |
|
STATUS_VALUE |
1 |
Report a notification if either the StatusCodeor the value change. The Deadbandfilter can be used in addition for filtering value changes. For floating point values a Servershall check for NaN and only report a single notification with NaN when the value enters the NaN state. This is the default setting if no filter is set. |
|
STATUS_VALUE_TIMESTAMP |
2 |
Report a notification if either StatusCode, value or the SourceTimestampchange. If a Deadbandfilter is specified, this trigger has the same behaviour as STATUS_VALUE. |