GFK-1527A Chapter 3 Configuration Requirements 3-3
3
Configuring Shared I/O References
Shared I/O data is transferred from the active CPU to the backup CPU each sweep. Reference
addresses and ranges must be confi g u r ed for the data to be transferred. Th er e can be up to 20
Kbytes of input data (%I, %AI) and up to 28 Kbytes of output data (%Q, %AQ, %M, %R)
transferred.
Input references should be transferred to the backup unit if the program logic requires identical
inputs for the two units. Scanning the same Genius I/O blocks in both units is not sufficient to
guarantee that the inputs will be identical every sweep.
When using the GDB Control Strategy, it is necessary to transfer all Genius outputs for redundant
blocks. Otherwise, the Genius blocks would drive their outputs from the backup when the Primary
PLC was serving as the backup.
Parameter Default Range Description
%I Ref Adr %I00001 00001 to 12288* Starting address for redundant %I data region. Must
be byte aligned.
%I Length 0 0 to 12288* Bit length of the redundant %I data region. Length
must be a multiple of 8.
%Q Ref Adr %Q00001 00001 to 12288* Starting address for redundant %Q data region. Must
be byte aligned.
%Q Length 0 0 to 12288* Bit length of the redundant %Q data region. Length
must be a multiple of 8.
%M Ref Adr %M00001 00001 to 12288** Starting address for redundant %M data region. Must
be byte aligned.
%M Length 0 0 to 12288** Bit length of the redundant %M data region. Length
must be a multiple of 8.
%R Ref Adr %R00001 00001 to %R
configured limit Starting address for redundant %R data region.
%R Length 0 0...%R configured
limit Word length of the redundant %R data region.
%AI Ref Adr %AI00001 00001 to %AI
configured limit Starting address for redundant %AI data region.
%AI Length 0 0 to %AI
configured limit Word length of the redundant %AI data region.
%AQ Ref Adr %AQ00001 00001 to %AQ
configured limit Starting address for redundant %AQ data region.
%AQ Length 0 0 to %AQ
configured limit Word length of the redundant %AQ data region.
Limit is 2048 for IC697CGR772; **Limit is 4096 for IC697CGR772