Casella CEL Indoor air quality monitor - Manual (Page 38)

12.9 CEL-254 Sound Level Meter
The CEL-254 Digital Impulse Sound Level Meter
satisfies the requirements of the international and
national IEC 60651 Type 2, BS 5969 Type 2, and
ANSI S1.4 Type 2A standards for both free field
and random incidence sound level meters.
It also satisfies the requirements of IEC 60651
Type 2I for impulse sound level meters.
The instrument provides a clear and unambiguous
digital indication of the A- and C-weighted sound
levels and overload conditions on an easily read
display. It features the standard Fast and Slow
time weightings, and can measure sound levels
between 30 dB(A) and 135 dB(A) in two ranges,
at frequencies between 10 Hz and 20 kHz.
In addition, the CEL-254 includes a standard
Impulse time weighting with reset function,
indicates battery voltage on the display, and has a
maximum hold function that operates with all
time constants.
Conditioned AC, and logarithmic DC outputs are
available from a single standard 3.5 mm 3 pole
coaxial socket, for use with logging systems, plus
level/time and tape recorders.
When the CEL-254 is required as a noise input, it
is recommended that it is specified at the same
time as the Microtherm indoor air quality. This is
because individual offset and multiplier values for
the sound level meter must be pre- programmed
into the system firmware at the factory.
Therefore, order a complete CEL-254/K1 Kit plus the special connection cable
SC233. The kit includes a CEL-282 Acoustic Calibrator, microphone cover and
carry case. The Calibrator is needed to perform field accuracy checks on the
sound level meter, as required by most measurement protocols.
If a CEL-254 is to be installed at a later date, it is recommended that the
Microtherm unit be returned to Casella CEL for the offset and multiplier values to
be pre-programmed into the system firmware.
Warning !
DO NOT use the 3.5 mm socket for power
One end of the SC233 cable is connected to the 3.5 mm coaxial socket in the
bottom of the instrument case with the other end plugged into channel 6 (see
Section 2.2).
Noise values will then be available from channel 6 of the data logger.
Sensor Specifications
Page 38 of 42
MICROTHERM indoor air quality &
WinIaq Application Software - User Manual