Rockwell Automation 2755 Enhanced Decoder Series B - Manual (Page 37)

3–7 Overview of Decoder Operations
Publication 2755-833
Storage memory can be thought of as programmable read only
memory (PROM). The default parameters are stored as read only
(EPROM), while the user changeable portion as retentive EEPROM.
for the sake of simplicity and consistency with earlier versions of the
DS/DD decoders, we will maintain the conventions that the Save and
Recall commands will ask for confirmation to “SAVE
CONFIGURATION CHANGES TO EEPROM . . . Y/N?” and
“RESTORE CONFIGURATION FROM EEPROM . . . Y/N?”
Memory Contents at Startup
Until you have modified and saved your own configuration
parameters, the decoder storage memory will contain only the
permanent factory default configuration. The first time you start the
decoder it will create a copy of those factory defaults in operating
memory.
Even on decoders without the optional battery, once you have saved
them to storage memory you will retain most of your configuration
parameters even with an extended loss of power. When you restart
the decoder it will read the saved configuration parameters rather
than the factory defaults. Parameters and values not retained after
extended power loss without a battery include:
•
Extended Match Code Table Configuration, which will be lost
and reset to factory defaults
•
Primary Match Code Table counts, which will be lost and reset to
zero
•
Host Replacement Rule Examples (which are the test examples
you have entered on the bottom half of the Host Message
Replacement Rules screen). These examples will be lost and the
example section of the screen will be cleared. Note that the rules
themselves will be retained.
The long life of the optional battery makes it unlikely that any loss of
configuration or data will occur during any conceivable power
outage in battery-backed decoders.