Bacnet Numeric Trend Log Ext (bacnet-BacnetNumericTrendLogExt)
This extension resides on the a BACnet device. You can export the history created by this extension as a fully-compliant BACnet trend log object.
Only the following read-only properties qualify for initial value setting during object creation. Requests that include non-qualified properties from the client cause a request to fail.
- Device Status Facets
- Discovery History Type
Figure 81. Bacnet Numeric Trend Log Ext properties
To access these properties, expand and double-click the BacnetNumericTrendLogExt.
In addition to the common properties (Status, Enabled and Fault Cause), this component has these properties.
| Property | Value | Description |
|---|---|---|
| Active Period, Start Time | Date and Time selectors |
Configures when to start the log.
|
| Active Period, Stop Time | Date and Time selectors |
Configures when to stop the log.
|
| Active | read-only |
Indicates the current state of the trend log based on the
Active Period.
|
| History Name | BFormat string (defaults to %parent.name%) |
Defines a pattern for deriving the name of the history created by this extension. It can be static text or a simple pattern
that allows the actual history name to be derived from the context. The default value (%parent.name%) sets the history name in the Id to the name of the parent of this extension. Changes to this property cause the format to
be reapplied and the history Id in the history config is to be updated.
|
| History Config | additional properties |
Serves as a container for sub-properties used to configure the attributes of the history record stored in the History space.
A separate topic documents these properties. |
| Last record | read-only |
Stores a copy of the most recent record successfully appended to the history for this extension.
|
| Interval | hours, minutes, seconds |
Controls data collection behavior for this Trend Log component.
If the If the |
| Precision | 32 bit (default), 64 bit |
Selects 32 bit or 64 bit options for the history data logging. The 64 bit option allows for higher level of precision but consumes more memory.
|
| Min Rollover Value | number (defaults to null) |
Defines the starting point for calculations for cumulative logging after a rollover. Rollover occurs after a running total
maximum value is reached. Select the null option if a
Min Rollover Value is unknown.
|
| Max Rollover Value | number (defaults to null) |
Defines a maximum value for calculations when a rollover is detected by the history logging process. Using this parameter
and the
Min Rollover Value parameter helps you avoid getting negative numbers when you are logging total data, such as energy usage.
|
| Total Record Count | read-only |
Indicates the total number of records collected by the Trend Log object since creation. When the value of Total Record Count
reaches its maximum possible value, the next value it takes is zero.
|
| Change Tolerance | text |
Specifies the minimum change in value that must occur before the system writes a record to the database.
|