7 Common parameter type definitions ToC Previous Next

7.10 DataChangeTrigger ToC Previous Next

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 StatusCode associated with the value changes. See Table 183 for StatusCodes defined in this document. OPC 10000-8 specifies additional StatusCodes that are valid in particular for device data.
STATUS_VALUE 1    Report a notification if either the StatusCode or the value change. The Deadband filter can be used in addition for filtering value changes.   For floating point values a Server shall 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 SourceTimestamp change. If a Deadband filter is specified, this trigger has the same behaviour as STATUS_VALUE.

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