MAN2285-9
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Detector sensitivity is based on the fast histogram during FastLearn and is thereafter based on the currently
active slow histogram. However, although the positions of the alarm flags are based on the slow histogram,
sudden changes in smoke density are picked up by the fast histogram so that early warning is given.
Sensitivity:
The current absolute sensitivity of the detector in percentage obscuration per metre (% obs/m)
Mean:
The current mean value of smoke density, taken from the currently “active” histogram and given as a
percentage of full scale deflection.
Variance:
The “spread” of data in the currently “active” histogram and given as a percentage of full scale
deflection.
FastLearn:
If the detector is currently in FastLearn mode, this will show the number of minutes remaining in the
FastLearn period. When this period has elapsed it will read “OFF”.
Alarm factor:
This is the
ClassiFire
alarm factor (see Section 4.6, “Alarm factor”)
Day/night:
This indicates the currently active slow histogram
Alarm levels:
These figures give the position of the various alarm flags in terms of a percentage of full scale
deflection.
Detector output:
This shows the real-time variation in background smoke levels in terms of a percentage of full
scale deflection.
5.2
Chart recording
The chart recording function shows how smoke density in the protected area has varied over time. The chart
may be downloaded to disk or printed out from a connected printer.
To access the chart log, select the menu options “View > Chart recording…” or click the symbol indicated below.
The following screen appears:
The red trace is the current alarm level and the black trace is the detector output. By moving the cursor along
the chart, the “Chart information” window (shown at the bot
-tom left) updates to show the date and time,
detector level and alarm level of the relevant period. The ‘File’ menu option in the chart recording
window
allows the chart recording to be saved to disk or printed to a connected printer, and allows a previous-ly saved
