5

Manual Output Controls and Diagnostics

Safety systems are often provided with controls for manual trip and manual override.

HA manual trip causes the output to assume the alarm condition. For example, a normally-energized output would be de-energized.

HA manual override causes the output to remain in the normal condition. For example, a normally-energized output is held energized.

These manual controls can be implemented either in hardware, as represented below, or in software. If the software method is used, the GMR autotest and fault processing operations are unaffected.

Hardware control usually consists of switch contacts applied to the output circuit, as shown below for a normally-energized output.

+24V

Source

Genius

Block

Sink

Genius

Block

Manual

Override Source

Genius

Block

Manual Trip System Input

LOAD

Sink

Genius

Block

 

Manual

System Input

Override

 

+0 VDC

In this circuit, operation of either the trip or override switch can cause no-load faults, state faults, and autotest faults to be generated. If these manual inputs are wired in the GMR system, fault reporting is modified to suppress no-load faults and Failed Switch faults. Use of manual controls does not affect fault reporting for Short Circuit, Overtemperature, Overload, or Discrepancy faults.

GFK-0787B

Chapter 5 Diagnostics

5-23

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Image 83
GE GFK-0787B user manual Manual Output Controls and Diagnostics