Concept
Change of Value Trend Logs
The change of value trend log records the variable each time the difference between the current value and the last log value exceeds the delta. Use the change of value trend log to, for example, record a variable that has an unequal oscillation.
The change of value trend log is limited to 10 records per second.
Do not set the delta too small since this can quickly fill up the trend log.
For example, in the figure below, the change of value trend log records a variable every time the variable exceeds or falls below the delta of 3. The records are printed in a trend chart. Notice that the change of value trend log records the values without any time perspective between the records.
The change of value trend log, which is not a variable triggered trend log, has the function to start log records according to a given start condition. For more information, see Trend Log Activation .
You can configure the maximum log interval in a change of value trend log. The maximum log interval is the maximum time that can elapse between two recordings regardless of whether the value has changed or not. The maximum log interval is calculated from the last actual recording. When the maximum log interval is configured, it bypasses the delta and the recording is triggered when the configured time period has elapsed.
A change of value trend log can be created with initial meter settings . The change of value trend log supports the meter change command and meter consumption calculation. You can view the last meter change information on the change of value trend log object. For more information, see Meter Function .
Trend Log Types
Creating a Change of Value Trend Log
Configuring a Change of Value Trend Log
Trend Units
Trend Log Activation
Log Record Storage
Meter Function
Change of Value Trend Log Properties – Basic Tab
Change of Value Trend Log Properties – Meter Info Tab
References Tab
Extended Trend Logs