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7-9GFK-0787B Chapter 7 Programming Information
Register (%R) Memory Assignment for GMR
The GMR software uses several areas of %R memory for specific functions, as
diagrammed below. Only the area labelled “Application Registers” should be used by the
application program. Within that area, a portion is reserved for initialization data, as
explained below.
%R and %M
Initialization Data
Defaults
64 words
64 words
64 words
64 words
64 words
%R Memory Allocation for GMR
66 words
66 words
66 words
%R
1
%R
max–127
%R
max–191
%R
max–255
%R
max–319
%R
max–385
%R
max–451
%R
max–63
%R
max
%R
max–128
%R
max–192
%R
max–256
%R
max–320
%R
max–386
%R
max–452
%R
max–64
Global Data to be Sent
Global Data Received from PLC on
Bus a with highest serial bus address
Bus Controller N Interface
Bus Controller N–1 Interface
Bus Controller 1 Interface
Application Registers
%R
max–320+66xN
Global Data Received from PLC on
Bus a with lower serial bus address
Global Data Received from PLC on
Bus b with highest serial bus address
Global Data Received from PLC on
Bus b with lower serial bus address
.
.
.
Each PLC receives two sets of incoming Global Data from the other PLC(s). Both of these
are placed into %R memory, as can be seen in the diagram. Only one set is copied to %G
memory for access by the application program, however.
Directly ahead of the incoming Global Data in %R memory is a copy of the outgoing
Global Data. This data should be programmed using %G memory, not %R memory. The
GMR software automatically moves the data to the appropriate %R location prior to the
Global Data being sent.
Ahead of the Global Data areas of %R memory are additional areas used by the GMR
software for communications with I/O blocks (for functions such as autotesting and
diagnostics) and with other bus controllers on the bus. The overall length of this area
depends on the number of other bus controllers in the system.
%R Memory Required for Startup Initialization Data
%R and %M initialization data that may be received during startup are stored in %R memory
(the second set of incoming %M initialization data is stored there temporarily at startup).
The GMR Configuration Software default for the beginning of the initialization data is %R0001.
In addition, by default, the configuration software assigns %R0257 as the beginning location
for %M initialization data which is directly after the %R initialization data.