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Manual Input Controls

Safety systems often use controls for manual trip and manual inhibit. The GMR autotest and fault processing operations are unaffected by such controls.

HA manual trip causes the input to assume the alarm condition. For example, for a normally-energized input, the input is open circuit.

HA manual inhibit causes the input to remain in the normal condition. For example, for a normally-energized input, the input is held high even if the device is in the Off state.

These manual controls can be implemented either in hardware or in software.

Hardware control usually consists of switch contacts applied to the input circuit, as shown below for a normally-energized input. Repeat contacts of the control switches are often input into the system for reporting purposes.

Field Circuit

System Input

Manual Inhibit

System Input

Manual Trip

point 1

Source

Genius

Block

point 16

point 1

Source

Genius

Block

point 16

point 1

Source

Genius

Block

point 16

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GeniustModular Redundancy Flexible Triple Modular Redundant (TMR) System

GFK-0787B

 

User's Manual ± March 1995

 

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Image 26
GE GFK-0787B user manual Manual Input Controls