Casella CEL CEL-193 - Manual (Page 5)

Casella USA
17 Old Nashua Rd #15
Amherst, NH 03031 USA
be replaced, it must be appreciated that the meter movement employed in the instrument has. a very
strong magnetic field, hence care must be taken to ensure that small metallic particles are not attracted into
its air gap when the rear cover is removed. When the batteries have been fitted switch A (Fig. 1) should be
moved to the BATT position which will cause the condition of the batteries to be indicated on the scale. If
the indication falls below the scale banded 'Batt', both batteries must be changed. The batteries must be
removed as soon as they become discharged or if the instrument is to be stored.
The pre-amplifier may be fitted directly into its socket on the top of the instrument and rotated until it
locates in the keyway and then be pushed home. Alternatively, it may be mounted in a remote location on
the tripod type CT 3 and connected to the instrument via the 5-metre extension cable type CEL-2942/5 (10
metre and 20 metre cables are also available under the same part number with the suffix changed to 10 or
20 respectively).
Having connected the pre-amplifier it is a simple matter to screw the microphone onto the pre-amplifier. It
is not necessary to secure the microphone more than 'finger tight' as excessive force on the capsule could
distort the diaphragm and thereby affect its calibration. It is recommended that the instrument is always
used in conjunction with the CEL-2962 Windshield and this is simply pushed over the microphone and pre-
amplifier assembly. In line with accepted instrument practice ensure that the instrument is switched off
whenever connections or disconnections are made.
The instrument itself may be handheld or, for long measurements, it may be mounted on the tripod, CT-3,
by means of the bush located in the rear cover.
Figure 1
2.2 Controls and Indicators
This section gives a general' description of the functions of the various controls and will enable those
unfamiliar with acoustic instrumentation to quickly establish the correct operational procedures.
(a) ON/OFF
In the OFF position, no functions are performed and there is no drain on the instrument batteries. In the
BATT position the charge state of the lower of the two batteries is indicated on the meter and as long as it
indicates within the scale band marked 'Batt' there is sufficient power to operate the instrument to
specification. When in the ON position, the instrument carries out its selected functions.
(b) L
eq
/SPL/MAX
The answer to be displayed on the meter is chosen by the setting of this control. In the SPL position the
varying sound level is displayed. When the Leq setting is selected the value accumulated since reset for
either equivalent continuous sound level, Leq, the single event noise exposure level LAX, or the ‘takt
maximum' value, LTm, as selected by switch 'e', is displayed.
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