Allen-Bradley controllogix 1756-L61, Application Book

Page: 9 / 56

Publication LOGIX-AP007B-EN-P - January 2007
CompactFlash Card Enhancements Overview 9
Possible Applications of
the CompactFlash File
System
Using RSLogix 5000 software, version 16 or later, and using the application
provided in this publication, you can read and write data to the CompactFlash
card. This could include tag values, recipes, or data log information, just to
name a few.
A possible application would be to store a collection of recipes on the
CompactFlash card. Whenever a recipe needs data, it can be read from a file
on the CompactFlash card. Then if changes were made to the recipe the data
could then be written back to the CompactFlash card for later use.
CompactFlash cards can also be read and written to with a personal computer,
using a CompactFlash card reader. However, using the methods described in
this document, tag values will be written out as binary data to the
CompactFlash card.
Attempting to open the file in a text editor will work, but the contents
displayed will be the ASCII equivalent of the binary data. The application will
not allow for files to be created on a personal computer and then read into the
controller, because checksums are embedded into the data. If you create a file
on the personal computer, it will not have the checksums embedded. When
the data is read it will fail the checksum test.
There are numerous possibilities with this feature, but there are some clear
restrictions that are explained in Chapter 2, CompactFlash File System
Restrictions.