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3-9GFK-0787B Chapter 3 Output Subsystem
Redundancy Modes for Output Blocks
There are three separate configuration processes for a GMR system:
GMR configuration, which supplies parameters used by the GMR system software.
PLC configuration, which is performed as usual for a Series 90-70 PLC system using
the Logicmaster 90 software.
Genius block configuration, which sets up the operating characteristics of the blocks
themselves.
It is during Genius block configuration that the redundancy mode of blocks is selected.
This is particularly relevant to the operation of output blocks. The four possible choices
for redundancy mode are:
A. GMR
B. Hot Standby PLC Redundancy
C. Duplex PLC Redundancy
D. No PLC Redundancy
Blocks in an output group must be set up for GMR mode. This changes the operating
characteristics of the block as described.
Individual output blocks (or combination I/O blocks) can be set to any of the latter three
modes (above). Block operation in these modes is described in the Genius I/O System User’s
Manual and in the Genius Discrete and Analog Blocks User’s Manual.
If an individual block is configured for Hot Standby redundancy mode, it can be included in
the GMR configuration as a Non-voted Discrete Group.
Blocks that are set up for Duplex PLC redundancy or no redundancy are not autotested.
They operate in the same manner as Duplex blocks in a non-GMR system.
GMR Mode
Configuring a block for GMR mode changes its operating characteristics as described below.
GMR mode supports non-redundant outputs with or without pulse test, and
redundant outputs with or without output autotest.
To prevent false Failed Switch diagnostics during switching transitions, detection of
Failed Switches is delayed for one second.
For the 16-circuit DC block, detection of No-load faults is delayed for one second.
This prevents No-load faults being falsely reported during switching transitions.
Operation of Block OK LED is modified. For the 16-circuit DC block, the Unit OK
LED does not indicate No-load faults when the block is in GMR mode. This is
necessary, since blocks may share output loads.
Modified fault reporting. In GMR mode, blocks automatically report faults to bus
controllers at serial bus addresses 29, 30, and 31.