Allen-Bradley controllogix 1756-L55M12, User Manual

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119 Publication 1756-UM001G-EN-P - January 2007
Chapter
11
Maintain Nonvolatile Memory
Introduction This chapter explains how to maintain nonvolatile memory.
The 1756-L6 x controllers support the 1784-CF64 CompactFlash card
for nonvolatile memory. The 1756-L55M22, 1756-M23, and 1756-M24
controllers have built-in nonvolatile memory.
Nonvolatile memory lets you keep a copy of your project on the
controller. The controller does not need power to keep this copy.
You can load the copy from nonvolatile memory to the controller’s
user memory:
•
each time you apply power.
•
whenever there is no project in the controller and you apply
power.
•
at any time via RSLogix 5000 programming software.
Topic Page
Choose a Controller That Has Nonvolatile Memory 120
Use a CompactFlash Reader 121
IMPORTANT
Nonvolatile memory stores the contents of the user memory when you store the
project.
•
Changes made after storing a project are not reflected in nonvolatile memory.
•
If you change to the project but do not store those changes, you overwrite them when
you load the project from nonvolatile memory. If this occurs, you have to upload or
download the project to go online.
•
If you want to store changes such as online edits, tag values, or a ControlNet network
schedule, store the project again after you make the changes.