TM0048
LaserNET Program User's Guide
September 2003
6-12
When enabled, a short-term running average of the smoke level is stored in memory and used to display as
the smoke level, the average calculated for the time period. The time period is programmable for 2, 4 or 8
seconds.
Figure 6-11. Signal Averaging Screen
To enable the function:
1. Access the menu by
Options>Configure>Signal Averaging.
2. Check the Signal Averaging box.
3. In the Signal Averaging Period field, select either
2
,
4
or
8
seconds.
4. Select
<OK>
to save the configuration.
6-5.6
Referencing
This feature is only available when using an IIM. Certain installations using HART XL may have HVAC
systems which provide make-up air from outside the monitored space. Sometimes this make-up air comes
from outside the building and will contain elevated levels of separate particles or low levels of smoke, often
caused by vehicle exhaust fumes, chimney soot or general urban pollution. This will then elevate the back-
ground smoke level in the monitored space and may cause unwanted alarms.
Referencing is a means of eliminating high background smoke levels caused by outside influences. One
Detector is assigned to monitor the make-up (or outside) air. The smoke level value of this reference Detec-
tor is then subtracted from the smoke levels of the other detectors assigned to this reference Detector.
The following conditions apply to referencing:
The reference Detector is the Detector which monitors the make-up or outside air. There can only be
one reference Detector in the system.
A Detector which uses the reference unit will have the reference detectors smoke level (up to 30%)
subtracted from its own smoke level.
The referencing feature should only be used when the normal ambient conditions in the air outside the
monitored space cause a 10% to 30% deflection on the smoke level bar graph display.
A fault will be generated in the Fault box on the main screen if the reference Detector exceeds 30%.
Any Detector which is configured to use a reference unit will show a fault if a reference Detector is not
defined.
The reference Detector does not report alarms.
1. Select
Options>Configure>Referencing
from the menu to open the Signal Referencing window (Fig-
ure 6-12) and show the current settings.
Summary of Contents for HART XL
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