Casella CEL CEL-281 - Manual (Page 100)

Provided the CEL-281 is not in calibration delay mode or calibration
mode, and the display is switched ON, it can be used as follows to ob-
tain and display noise dose information at any time, without interrupting
any logging that might otherwise be occurring.
1. Load and/or check batteries, perform a field accuracy check
(acoustic calibration), select time and frequency weightings, and
enter the fully operational state with the display switched ON,
(with or without data logging) as described in Chapter 4.
If the instrument has just been calibrated or the 20 second
calibration delay period has elapsed, it will enter the sound level
meter measurement area automatically.
The LAVG legend will appear, while the main display shows
average sound levels in dB, either using whichever of the time
weightings and frequency weightings have just been selected,
or those used last time the instrument was operated.
2. Press the key to enter the noise dose measurement oper-
ational area.
If data is being logged, logging will continue uninterrupted, but
the display will change to indicate whichever of percent dose
(% Dose) or projected percent dose (P% Dose) was used last
time the instrument was operated, using whichever of the time
weightings, frequency weightings, and exchange rate values
(Q) were used last time
1,2
.
Note : If the logging run is still in progress, the displayed value may be seen to change
to new values.
Note : The time constant used for the dose values displayed will be the constant set
at the time the data was stored.
3. Press the key again to change from % Dose measurement
to P% Dose measurement, or vice versa.
Obtaining Required Results
CEL-281 Operator's Handbook - Page 91