Rockwell Automation Publication 2080-UM002N-EN-E - November 2022 241
Chapter 12          Using microSD Cards
Data Log Directory Structure
 
The following table summarizes data logging performance on Micro800 controllers. 
The DATALOG folder is created under the current project directory in the microSD card. In 
this example, the current project directory is MYPROJECT. By default, the current project 
directory name is taken from the downloaded project’s controller name or from the 
ConfigMeFirst.txt. See ConfigMeFirst.txt Configuration Settings
 on page 236.
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, 2019, the subfolder 2019 
is created under DATALOG. Under the 2019 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 data log 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 data log 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 data logging based on that information. 
These data log files 
are for February 2, 
Data Log 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 data log 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