Rockwell Automation 2080-LC20-20QBBR Micro820 20-point Programmable Controllers User Manual - Manual (Page 87)

Rockwell Automation Publication 2080-UM005A-EN-E - December 2013 79
Using microSD Cards Chapter 9
Datalog Directory Structure
The following table summarizes datalogging performance onMicro820
controllers.
The DATALOG folder is created under the current project directory
in the microSD card. This folder is created by default unless another
directory has been specified in the ConfigMeFirst.txt. See
ConfigMeFirst.txt Configuration Settings on page 76 .
Subdirectories are also created following the controller RTC
timestamp. This means that if RTC date at the time of function block
execution is February 02, 2013, the subfolder 2013 is created under
DATALOG. Under the 2013 folder, the subfolder 02 (which stands for
the month of February) is created. Under 02, another subfolder 02 is
created, corresponding to the current date.
Under the current working folder, the subfolder Grp01 is created. A
maximum of 50 Grpxxx folders can be generated on the microSD
card per day.
Under the current Grpxxx working folder, the datalog file File01.txt
is created. Once this file reaches more than 4 KB, another file,
File02.txt, is automatically created to store data. The file size is
kept small in order to minimize data loss in case the card is
removed or when there is unexpected power off.
Each Grpxx folder can accommodate up to 50 files. This means that,
for example, when the Grp01 folder already stores 50 files, a new
folder Grp02 is automatically created to store the next datalog files
for that day. This automatic folder and file generation goes on until
the Grpxx folder reaches 50 for that day.
When a microSD card is inserted, the DLG function block looks for
the last Grpxx folder and filexx.txt file, and proceeds to do the
datalogging based on that information.
These datalog
files are for
February 2, 2014.
Datalog Specifications
Attribute Value
Maximum datasets 10 All datasets are stored in the same file.
Maximum variables per dataset 128 Configured in Connected Components
Workbench software.
Minimum size per file 4 KB
Maximum files per Grpxx folder (1)
(1) Once the datalog limits is reached (that is, 50 Grpxx folders per day, then an error (ErrorID 3:
DLG_ERR_DATAFILE_ACCESS) is returned.
50 When directory is full, a new directory is
automatically created in RUN mode.
Maximum files (Filexx.txt) per day 50 When file reaches maximum size, a new file is
automatically created in RUN mode.
Typical data per day 10 MB