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.
All trend logs use circular storing. How many records a trend log can store before overwriting old ones depends on the trend log configuration.
Para obtener más información, consulte Log Record Storage .
The interval trend log and change of value trend log start recording values when the configured activation conditions are met. If an activation variable is used, both the activation variable and the activation time have to be true for the trend log to start recording.
Para obtener más información, consulte Trend Log Activation .
You use an extended trend log to transfer records from a trend log. An extended trend log can be connected to a trend log or connected in a series to another extended trend log. Only one extended trend log can be connected to a trend log.
Para obtener más información, consulte Extended Trend Logs .