GE GFK-0787B Noise Reduction Machine User Manual


 
2
2-2 Genius Modular Redundancy Flexible Triple Modular Redundant (TMR) System
User’s Manual – March 1995
GFK-0787B
Overview
The input subsystem is the part of a GMR system that gathers input data. It may consist of:
GMR Input groups of 1 to 3 discrete or analog blocks
Individual non-voted discrete and analog blocks
The following illustration represents basic elements of an input subsystem.
Triple Input Sensors
Triple Genius Busses
Triple PLCs
ABC
Input Block Group
Non-voted
(non-redundant)
Input Block
GMR blocks are arranged in “groups” of 1, 2, or 3 blocks. Within a group, all the blocks must be
the same type. The input group shown above consists of three Genius blocks. Each has its own
input sensors monitoring the same parts of the application process. Each block sends the input
data from its sensors to three Series 90-70 PLCs. For simplification, the illustration only shows one
input circuit on each block. However, each group can serve multiple GMR inputs. In addition,
circuits that are not needed for GMR inputs can be used for non-voted inputs or outputs.
Genius blocks broadcast their inputs. So each block’s input data is received by all PLCs on the
bus. The GMR system software in each PLC then performs input voting and provides the results
to its application program. If all input data is not available, the software follows a configured
voting adaptation scheme. Details of both discrete and analog input voting are in the PLC
chapter.
In addition to the diagnostics capabilities of the Series 90-70 PLC and Genius I/O blocks,
the GMR system provides autotesting and discrepancy reporting for GMR inputs.
Genius blocks configured for GMR operation automatically generate three copies of
their standard Genius fault report messages. They send one copy to the PLC Bus
Controller configured with serial bus address 31, one to 30, and one to 29. So all of the
GMR PLCs are able to monitor the blocks for Genius diagnostics.