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Reference Manual
00809-0100-3003, Rev AA
Section 4: Operation
4.1
Normal operation
On power-up the GDU-Incus initializes a diagnostic check and then enters normal operation mode as
per factory defaults supplied.
Factory Op mode 71 settings;
•
4-20 mA = 40-120 dB (Linear scale factor)
•
Display brightness set to 12. Viewing distance over 33 ft. (10 m) in an outdoor environment
•
Real time instantaneous ultrasonic sound level shown on display in dB
•
Relays are energized open, loss of power causes alarm (fail-safe)
•
Relays are set to non-latching
•
Reset alarms enabled; allows latched relays to be reset and restarts alarm delay
•
Alarm level set at 70 dB for relay output
•
Delay time set to 15 seconds for relay output
•
RS485 ID set to 1
•
All communication ports are active and ready to receive commands
4.1.1
Alarm level
The 'Alarm Level' is the ultrasonic sound level at which an alarm state is triggered. During the alarm
state the display flashes, the relays switch states and the current loop becomes active if one or more
sensors were in fault mode (if no sensors are in fault the current loop will already be outputting dB
level).
To avoid false alarms it is recommended to set the alarm level above the background level established
by mapping when all processes are operational. If the background level is unknown it is recommended
to analyze the background using the detector itself. Care should be taken to observe all processes that
may cause intermittent ultrasonic noise such as pressure relief valves.
Please contact an Emerson representative for advice on alarm levels.
Note: the higher the alarm level the smaller the detector coverage radius, it is therefore important to
establish a safe alarm level at the lowest permissible value.
May 2019
23
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