Recording Data

The Log Manager uses two types of files to record historical data:

•      Data Files (.DAT)

•      Log Files (.LOG)

These files are described as follows:

Data Files (.DAT Files)

Logger tags log their values to a specialized data file (or series of data files) whose naming convention uses the name of the tag whose data is being logged by the logger, followed by the extension ".DAT" (for example, "AI20_1.DAT"). These ".DAT" files are in an encrypted binary file format. For the standard Logger tag type, only one data value, the tag's value, is stored per file. A timestamp, as well as the validity status of the data, is stored with each record.

Information on setting a specific location for the data files for your application can be found in Specify a Location for Data Files and Log Files.

Log Files (.LOG Files)

In addition to the data file, a log file (with the extension "LOG"), is used to record the names of the data files for a tag with an associated logger tag. The name of this log file is always tagname.LOG (i.e. the name of the tag for which the historical data file is being created (e.g. "AI20_1.LOG").