# Log File

When the device Log File is enabled, memory space is reserved to store RTU events and Channel State transitions. The amount of space reserved is determined by the Log File Size parameter. With the Log File device, you can select any combination of the following "items to be included" in the log file:

- Session History
- Channel State Changes
- Data Samples
- Alarms
- Alarm Acknowledgment
- Alarm Resets to Normal

Parameters directly relating to the Log File include:

- Data Sampling Base Time and Frequency: Determines when and how often channel data is written to the Log File
- Log File Size: Determines the amount of memory reserved for the Log File
- Log File High-Water Mark: When this percentage of reserved memory is used, RTU calls destinations with log report capability.
- Remote Data Terminal or Fax Machine: These are the only destination types currently supporting log file reports.

See Also

Log File Advanced Settings

Log File Advanced Concepts

Remote Data Logging

Log File Event Examples