Delay Time - Emerson GDU-Incus Reference Manual

Reference Manual
00809-0100-3003, Rev AA
4.1.2

Delay time

To avoid spurious alarms it is recommended that a delay time be used for non-toxic gas applications or
when instantaneous detection is not required. The delay timer is activated from the point at which the
alarm threshold is first exceeded. If the ultrasonic noise drops below the alarm level threshold the delay
time will be reset as shown in
threshold for the duration of the delay time the alarm will be activated as shown in
Alarm delay time should be assessed with regards to the following:
• Detector proximity to release valves and intermittent ultrasonic noise sources
• Process leak severity, toxic / non-toxic, acceptable leak size before alarm
•
Existing site protocols and local regulations
Note: If a gas leak occurs during spurious noise the delay time will continue from the first instance of
noise above the alarm threshold level.
Factory Default standard delay time is 15 seconds.
Figure 4-2 Graph Showing Alarm Activation with Leak
Figure 4-3. If the ultrasonic noise level remains above the alarm level
May 2019
Figure 4-2.
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