Rockwell Automation 57C423 Common Memory Module - Manual (Page 9)

2Ć1
2.0 MECHANICAL/ELECTRICAL
DESCRIPTION
The following is a description of the faceplate LEDs and the basic
circuit functions on the module.
2.1 Mechanical Description
The Common Memory module is a printed circuit board assembly
that plugs into the backplane of the DCS 5000/AutoMax rack. The
module consists of a printed circuit board, a faceplate, and a
protective enclosure. The faceplate contains tabs at the top and
bottom to simplify removing the module from the rack. On the back
of the module are two edge connectors that attach to the system
backplane. Module dimensions are listed in Appendix A. See figure
2.1 for module faceplates.
The faceplate contains two green status lights. The upper status light,
labeled BAT.OK", indicates whether the onĆboard battery is
providing sufficient voltage to retain the contents of RAM (ON)or
should be replaced (OFF). See section 3.3 for directions on replacing
the battery and Appendix A for battery specifications. The lower
status light, labeled SYSTEM WATCHDOG", is lit only when the
module is in slot 0, the module has passed its powerĆup
diagnostics, and the bus arbitration clock is present on the
backplane. If the status light is off, it indicates the module is not
operational, either because it is malfunctioning or because it is
located in a slot other than 0 and is providing data storage only.
2.1.1 Checking the Status of the OnĆBoard Battery
The status of the Common Memory module onĆboard battery can be
checked in the following ways:
If the Common Memory module is in slot 0:
D the BAT. OK" LED on the faceplate will be ON to indicate the
battery is providing sufficient voltage to maintain the contents of
RAM memory and OFF if the battery should be replaced.
D the Info/Log Processor Information Display from the ON LINE
menu of the AutoMax Programming Executive will show the
battery status.
If the Common Memory module is not in slot 0 (i.e., it is in any other
evenĆnumbered slot and is being used for data storage only), the
battery status is indicated only by the status of the BAT.OK" LED on
the module faceplate.