Table of Contents
Advertisement
OMRON
Note:
Note:
Number of files in a Data Set
When a Data Set starts logging a file will be created to hold the logged items, this file is known as a
'Live' or 'Active' log file (There is only one Live file in a Data Set file set). When the time period
for a Data Set log file expires a new file is created with a more recent Timestamp, this file then
becomes the 'Live' file and the previous file is now known as a 'Dead' log file. Over a period of
time there can be many 'Dead' files in a Data Set but only one live one. If a limit has been set on the
number of dead files to be kept when this number is reached the oldest file will be purged
automatically as each new file is created.
The number of dead files to be kept for a particular Data Set is managed automatically by specifying
the 'Number of Files to Keep' from the Data Set Properties Parameters when a Data Set is created.
This field is only enabled when the 'Keep all files' check box is 'unchecked'.
Note:
For example, if the number of files to keep is set to 24 then there the system will keep 24 Dead files
and one Live file, i.e. 25 files in total.
WARNING: No backups are taken when a file is purged. If you wish to keep any data you
If the 'Keep all files' check box is checked no automatic purging will take place and the System will
store all the Dead files created until the disk is full.
Dead files can be copied, moved, deleted etc. as they will not be written to again by the System.
Live files may be copied (i.e. backed up to another directory) while the Log file is open but they
cannot be moved or deleted as they are locked by the System. In order to delete or move a live file it
must first be closed. See Opening and Closing Log Files.
Invalid Data Log Files
Data log files generated during one project sessions will continue to be used in subsequent sessions, if
they are still live. For example, if a system runs during the day and is shut down at night, then a Data
Set with a duration of 7 days will use the same file for the whole 7 days.
Release 2.0
Do not rename any log files while they are in the Data Logging directory or the File
Management System will not work correctly. The File Management System relies
on the strict format of the Data Log files to determine which file to open as Live
and which file(s) to delete during purging and also for performing 'previous/next'
file searches in the Data Log Viewer.
Additional files should never be copied into the Data Logging directory as the
automatic purging mechanism may delete all the log files.
There will always be one Live file for each Data Set.
must ensure that backups are taken before purging occurs.
CHAPTER 11 – Data Logging
Page 181
Advertisement
Table of Contents
