Chapter 3
Note: The percentage life remaining will not be accurate for NiCd
batteries. The battery symbol appears when battery voltage
becomes low, but the D
USTTRAK monitor runs considerably less
than 60 minutes before displaying the message “LO” and turning
off.
Figure 3–1: D
USTTRAK Display with All Elements Shown
After displaying the percentage of battery life remaining, the current time set
on the internal real-time clock is displayed. When the self-check is complete,
the D
USTTRAK monitor will be in Survey mode.
SAMPLE Key
Press the SAMPLE key to start/stop data sampling. The word “SAMPLE”
appears in the upper right corner of the display while the D
USTTRAK monitor
is taking a sample. When sampling is stopped, the D
USTTRAK monitor
automatically scrolls through statistics for the sample that just ended.
TIME CONSTANT Key
Momentarily press and release the TIME CONSTANT key to view the
current time-constant. To change the time-constant, press and hold the key
down. The available time-constant choices will scroll on the display. When
the desired value is displayed, immediately release the key.
The time-constant is actually an averaging period. The D
USTTRAK monitor
display is always updated every second. However, the reading displayed is
the average reading over the last time-constant period. For example, if the
current time-constant is set to 10-seconds, the display shows readings
averaged over the previous 10 seconds, updated every second. This is also
called a 10-second “moving average.”
As configured at the factory, the available time-constant values are 1, 5, 10,
15, and 30 seconds. The internal list of time-constant values can be altered
using T
RAKPRO Data Analysis Software supplied with the DUSTTRAK
monitor. The range of time constants allowed is 1–60 seconds. See the
following instructions.
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