Casella CEL CEL-393 - Manual (Page 87)

corrected by the amount shown on the barometer in order to compensate
for errors associated with atmospheric pressure and altitude.
If the calibration potentiometer of the sound level meter has been sealed
by the official calibration laboratory, a k factor should be applied to the
results in ensuing measurements, derived from the difference between
the corrected calibration level of the pistonphone and the actual dis-
played result. Otherwise adjust the calibration potentiometer with the trim
tool provided so that the corrected calibration level of the pistonphone is
shown on the sound level meter display.
To get the best from your CEL instrument and to preserve the calibration,
is is important that these procedures are followed along with due regard
to accepted good practice for the use of precision measuring instru-
ments. For example, always check calibrations (and batteries) at the
beginning and end of each measurement sequence and include the
results in the measurement report. It is also adviseable that the calibrator
undergoes full laboratory verification together with the sound level meter
if they are to be used in critical applications. Your CEL agent or distributor
can advise on these procedures.
9 BATTERY & AUXILIARY POWER
SUPPLIES
The CEL-393 is designed to operate with an alkaline manganese battery
(IEC type 6LF22) of the type provided with the instrument when new.
Zinc carbon batteries (IEC type 6F22) are not suitable. The approved
battery type will provide approximately 18 hours of operation for the A
and C versions, depending upon duty cycle.
When the filter function is being used in B or D versions, power consump-
tion increases considerably, hence a markedly shorter battery life will be
obtained. The actual life will depend upon the duty cycle, but it is
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