GE GFK-0787B User Manual

tModular Redundancy Flexible Triple Modular Redundant (TMR) System 

In a GMR system, the following references are reserved or assigned special functions:

%I0001 to %I1024 (788 CPU)
%I00001 to %I12288 (789 CPU

)

Input Table. Some references are automatically assigned by
the GMR Configuration Software. Others are available for
use, as explained in this chapter.

%Q0001 to %Q1024 (788 CPU)
%Q00001 to %Q12288 (789 CPU)

Output Table. Some references are automatically assigned by
the GMR Configuration Software. Others are available for
application use.

%AI0001 to %AI

max

The length of %AI data (shown at left as 

max

 ) is configur-

able. Some references are automatically assigned by the
GMR software. Others are available for application use.

%R

max– 320+ (66xN)

 to %R

mx

The  length of %R data is configurable. At left, the letter N rep-
resents the number of bus controllers on the bus.
The GMR software requires the use of several areas of %R
memory,  as detailed in this chapter.

%G0001 to %G0896
%GA0001 to %GA0896
%GB0001 to %GB0896
%GC0001 to %GC0896

The GMR software provides these memory areas for applica-
tion global data transfer. The correct method of program-
ming global data in a GMR system is described in this chap-
ter.

%M12225 to %M12256

System status bits

%M12257 to %M12288

System control flags

%R0001 to %R0256
(defaults: starting reference and 
length are configurable)

%R startup initialization data from another online PLC.
References shown at left are the defaults; refer to your GMR
configuration printout for the actual references used.

%R0257 to %R0272
(defaults: starting reference is con-
figurable)

%M startup initialization data from another PLC.  Refer-
ences shown at left are the defaults; refer to your GMR con-
figuration printout for the actual references used.
%M defaults to 16 words long.

With the exceptions noted above, the following memory areas can be written to if Write
Access is enabled during GMR configuration:

        %R

Registers

Analog Input Table

Analog Output Table

Discrete Input Table

Discrete Output Table

Temporary internal reference bits that are not saved through power loss

Internal reference bits that are saved through power loss

Global Data memory

Global Data memory

Global Data memory

For discrete (bit) memories: %I, %Q, %T, and %M, the starting reference must be on a
byte boundary 1, 9, 17, etc). Global Data %GA, %GB, and %GC memories are not
available. Those memory areas are used by the GMR system to exchange data (see
above), and cannot be accessed directly.

Page 6-23 describes configuration for setting up Write Access.