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7.10 DataChangeTrigger

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.

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