The function of a trend log is to log the variable that it is connected to and store the records.
To be able to store larger amount of records, you connect an extended trend log. The records of the trend log and the extended trend log can be presented numerically in a trend log list or graphically in a trend chart. The records can also be processed by a calculation method before they are presented.
During the logging process, activity in the server may be temporarily increased. This is because a second polling rate is applied to each variable 30 seconds before the logging time. With multiple logs, the increase in activity can be significant. After 30 seconds, when a value is logged, the polling rate is set to the maximum integer.
You use a trend log to collect data and then store the records. A record contains a log value or an event as well as its time stamp and an optional comment. A trend log can log an analog variable, a digital variable, or an integer variable.
For more information, see Trend Log Types .
All trend logs store records by using the circular storing principle; you can also connect trends logs to external trend logs with larger storing capacity. For some trend logs you can set up conditions that have to be fulfilled before the trend log starts recording.
For more information, see Trend Log Functions .
You can define the unit of a trend log when the trend log is created or on a previously created trend log where no unit has been set.
For more information, see Trend Units .
A trend chart displays the records of a trend log or an extended trend log as a series.
For more information, see Trend Charts .
The trend log list numerically displays the records of a trend log or an extended trend log. The records of the trend log can be processed by a calculation method before they are presented in the trend log list.
For more information, see Trend Log Lists .
You configure a multi trend log list to display values from multiple trend logs in one list. You compare values in a multi trend log list when you commission or validate an EcoStruxure BMS.
For more information, see Multi Trend Log Lists .
When moving or copying a trend log or extended trend log to another EcoStruxure BMS server, only the configuration of the trend log is transferred. If you copy the trend log to another EcoStruxure BMS server, all recorded values are preserved in the original trend log while the copy on the other EcoStruxure BMS server does not contain any recorded values. If you move the trend log to another EcoStruxure BMS server, the configuration of the trend log is preserved but the record values are lost.
You use the mass create feature to create multiple identical alarms or trend logs for different objects, instead of creating the alarms or trend logs one by one. From trend logs, you can mass create extended trend logs.
For more information, see Mass Create .
Using WebStation you can display a list of unconfigured trendlogs to identify the trendlogs that needs to be started or configured. From the list you can start and configure trendlogs.
For more information, see Displaying a List of Unconfigured Trendlogs in WebStation .