Battery Replacement/Memory Protection Factors; The Importance Of Backing Up Your Program - GE 90-30 PLC Series Installation And Hardware Manual

Battery Replacement/Memory Protection Factors

Since there are differences in each PLC application, each user will have to determine on an
individual basis what strategy to use. There are several factors to consider when planning a battery
replacement/memory protection strategy:

The Importance of Backing up Your Program

Regardless of what strategy you use to maintain PLC memory, you should always keep an up-to-
date backup copy of your application program. Other suggestions to help minimize down time:
GFK-0356Q Chapter 6 Memory Backup/Battery Backup
How critical is the application? Will considerable loss be sustained if the PLC goes down? If
so, frequent replacement of the battery would be a wise choice. For critical applications, the
cost of a battery would be quite low in comparison to the cost of a PLC shut-down.
How readily can a backup program be loaded? Are there technicians on-site who know how to
load a backup program? Is the backup program accessible at all times to those responsible for
maintaining the equipment? Is a personal computer or equivalent equipped with GE
programming software available at all times for use in loading the backup program?
Do you have a preventive maintenance program? A formal program would help ensure that
the battery is replaced on time. Some users replace the backup battery each year during their
annual shut-down period.
How accessible is the PLC? In some applications, the PLC may be mounted in a remote
location that is not easily accessed.
Safety codes. Some users may have safety rules that would not allow replacing the battery
with power applied.
How is the PLC used? Is power left on all the time, or is it shut down every day? See the
heading "Factors Affecting Battery Life."
Some users run without a backup battery by using one of the PROM options. See the section
below called "Operating Without a Memory Backup Battery" to determine if this strategy is
suitable for your application.
Make sure the backup copy is readily accessible to those who may need to use it.
Train more than one person to load the backup program in case that one person is not available
when needed. Information on creating a backup can be found in GE's software user's
manuals. This procedure is also covered in applicable GE programming software
training courses.
Ensure that a suitable computer is equipped with GE PLC programming software and
will be readily available to load the backup program to the PLC.
Create a written backup procedure. Fortunately, restoring your program from the backup copy
is probably not something you will do very often. As a result, however, some of the steps
could easily be forgotten.
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