<DataChangeFilter>

The <DataChangeFilter> and </DataChangeFilter> elements define the conditions where the change in the monitored item's value causes the server to generate a data change notification.

The <DataChangeFilter> and </DataChangeFilter> elements contain the following child elements:

`<Trigger>` `</Trigger>`	Identify the conditions under which the server creates a data change notification. The following list describes the valid values: Status_0: Generate a notification only when the status code associated with the value changes. StatusValue_1: Generate a notification when either the value or its associated status code changes. You can use a deadband filter, defined in the `<DeadbandType>` and `</DeadbandValue>` elements, to provide additional filtering of value changes. StatusValueTimestamp_2: Generate a notification when the value, its associated status code, or its source timestamp change. If you specify a deadband filter, this trigger operates in the same way as StatusValue_1. If there is no filter associated with a monitored item, the default trigger is StatusValue_1.
`<DeadbandType>` `</DeadbandType>`	Define the type of the deadband and is one of the following values: 0: There is no deadband filter associated with this value. 1: The filter is an absolute value. 2: The filter is a percentage.
`<DeadBandValue>` `</DeadBandValue>`	Determine when a notification resulting from a change in an item's value is generated. When `<DeadbandType>` and `</DeadbandType>` contain 1, this element contains the absolute change in the item's data value that causes the generation of a notification. For example, if this element contains the value 100, the server generates a notification if the item's value changes by 10 or more units. When `<DeadbandType>` contains 2, this element contains the percentage change in the item's range of data values that causes the generation of the notification. For example, if the item has a total value range of 250 and the value of this element is 10, the server generates a notification if the item's value changes by 25 or more units.

<Trigger> </Trigger>

Identify the conditions under which the server creates a data change notification. The following list describes the valid values:

Status_0: Generate a notification only when the status code associated with the value changes.
StatusValue_1: Generate a notification when either the value or its associated status code changes. You can use a deadband filter, defined in the <DeadbandType> and </DeadbandValue> elements, to provide additional filtering of value changes.
StatusValueTimestamp_2: Generate a notification when the value, its associated status code, or its source timestamp change. If you specify a deadband filter, this trigger operates in the same way as StatusValue_1.

If there is no filter associated with a monitored item, the default trigger is StatusValue_1.

<DeadbandType> </DeadbandType>

Define the type of the deadband and is one of the following values:

0: There is no deadband filter associated with this value.
1: The filter is an absolute value.
2: The filter is a percentage.

<DeadBandValue> </DeadBandValue>

Determine when a notification resulting from a change in an item's value is generated.

When <DeadbandType> and </DeadbandType> contain 1, this element contains the absolute change in the item's data value that causes the generation of a notification. For example, if this element contains the value 100, the server generates a notification if the item's value changes by 10 or more units.

When <DeadbandType> contains 2, this element contains the percentage change in the item's range of data values that causes the generation of the notification. For example, if the item has a total value range of 250 and the value of this element is 10, the server generates a notification if the item's value changes by 25 or more units.