Rockwell Automation 1756-HIST2G Historian ME 2.1 - Manual (Page 303)

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Glossary
This appendix contains a list of terms and definitions used with the FactoryTalk
Historian ME.
Term Definition
.ACD The file extension used for project files created by RSLogix
5000 software.
Add-on Profile (AOP) AOP is used by ControlLogix processors to identify and
determine characteristics of FactoryTalk Historian ME
modules.
Archive The historical record of time-series data maintained by the
FactoryTalk Historian ME server. It is the fundamental and
most important information store of the FactoryTalk Historian
ME server that contains the historical data record of all events
for all points.
Archive Event Any event that is stored in the archive.
Archive File A binary file that contains a section of the data archive
covering some finite time range. These files, defined by start
and end times, should be contiguous and nonoverlapping. Only
fixed archive files may be created.
Archive Gap A gap between the end time of one archive file and the start
time of the chronologically next archive file. Archive gaps are
not desirable because archive events with a timestamp during
the gap cannot be stored on disk in an archive file and will be
discarded. To avoid archive gaps, archive files should always
be created such that the end time of one archive equals the start
time of the chronologically next archive.
Archive Shift The process of clearing the oldest writable and shiftable
archive file and making it the new primary archive. An archive
shift typically happens automatically when the previous
primary archive becomes full, but it sometimes must be
performed manually for maintenance and troubleshooting
purposes.