Basic Redundancy Options - GE Mark VIe Instruction Manual

2 Basic Redundancy Options

External Redundancy Options
Power Sources
Field Devices
Field Wiring
Each of these system components can be supplied in Simplex, Dual, or Triple Modular Redundancy (TMR) configuration.
Dual is more reliable than simplex, assuming that the component has a known failure mode. For example, if two pressure
sensors are known to fail low, then the control can be preconfigured to select the higher of the two signals. If the sensors or
the electronics that monitor the sensors have a less predictable failure mode, transiently or steady state, then dual redundancy
is insufficient.
Triple redundancy continuously monitors and votes three parameters so a partial or unpredictable failure of one component is
out-voted by the other two. In the case of three lube oil pressure switches, the protective system performs a simple logical
vote with no need to predict in advance a probable failure mode.
Simplex, dual, and triple redundancy can be implemented according to the specific needs of each application and site. This is
important for cost effective redundancy. For example, exhaust thermocouples are important inputs for running reliability and
tripping reliability on gas turbine controls, but wheelspace thermocouples are monitored-only. Therefore, different
redundancy strategies are used for exhaust and wheelspace thermocouples.
Product Redundancy Options
External Power Sources
Field Sensors
Internal Power Supplies
Input Redundancy - Local Processors
per I/O Module
Input Redundancy - Local Processors
per I/O Module
4 GEI-100728A
Internal Redundancy Options
Power Supplies / Converters
Controllers
I/O Network (IONET) Switches
I/O Modules
Simplex
1, 2, or 3
1, 2, or 3
1 or 2
1
1
Mark VIe Controls System Redundancy Options
Public Information
Dual
1, 2, or 3
1, 2, or 3
2
1 or 2
1 or 3
Triple
1, 2, or 3
1, 2, or 3
3
3
3