GE Mark VIe System Manual page 47

1.6.4 Output Processing
The system outputs are the portion of the calculated data transferred to the external hardware interfaces and then to the
various actuators controlling the process. TMR outputs are voted in the output voting hardware. Any system can output
individual data through simplex hardware.
The three voting controllers calculate TMR system outputs independently. Each controller sends the output to its associated
I/O hardware (for example, the R controller sends output to the R I/O). The three independent outputs are then combined into
a single output by a voting mechanism. Different data types require different methods of establishing the voted value.
The outputs from the three controllers fall into three groups:
• Outputs are driven as single ended non-redundant outputs from individual I/O networks
• Outputs exist on all three I/O networks and are merged into a single output by the hardware
• Outputs exist on all three I/O networks and are output separately to the controlled process. This process may contain
external voting hardware.
For normal relays, the three outputs feed a voting relay driver, which operates a single relay per channel. For critical
protective signals, the three outputs drive three independent relays, with the relay contacts connected in the typical six-contact
voting configuration.
For servo outputs, the three independent currents drive a three-coil servo actuator, which adds them by magnetic flux
summation, as displayed in the following figure. Failure of a servo driver is sensed and a deactivating relay contact is closed
to short the servo coil.
Control System Overview
Relay Output Circuits for Protection
Public Information
GEH-6721_Vol_I_BP System Guide 47