Casella CEL CEL-424 - Manual (Page 3)

Intrinsically safe versions are rated to EEx ia IIC T4 for use in
zones 0, 1 and 2 with IS Certificate Number - Ex97E2110X tested to
EN50020 (this corresponds to CENELEC apparatus group IIC, North
American grouping Class1).
3.2 CEL-420 Noise Dosimeter (& CEL-422/424/426)
The following features also apply equally to the CEL-420/422/424/426.
The CEL-420 series instruments are ideal for quick on-site surveys and
for monitoring personal noise exposure in accordance with European ISO
or USA OSHA and DOD stand-
ards. For dose measurement,
they are passive instruments
with settings that may be re-
viewed by key strokes, but
which can be selected only by
means of the dB10 (or dB12)
software. However, all sound
level measurement parame-
ters can be set from the key-
pad.
There are overlapping
measurement ranges: 50-120
& 70-140 dB, A & C RMS
weightings, Linear & C Peak
weightings, Fast, Slow &
Impulse time weightings, and energy exchange rates (Q) of 3, 4, 5 & 6.
In dose measurement mode, they display % dose, % dose projected for
an 8 hour period, peak level and measurement duration.
For those countries which are subject to European Union regula-
tions or the equivelent ISO standards, the instruments measure the daily
sound exposure level (L
Aeq,8hr Pa
2
h according to IEC 1252, that is identi-
cal with the L EX,8h required by ISO 1999), while for USA OSHA regula-
tions they measure the Time Weighted Average Level (TWA).
When used as a sound level meter they display sound level,
maximum sound level, peak and time-averaged (L Aeq or L Avg ) sound
levels.
3.3 CEL-460 Logging Noise Dosimeter
(& CEL-462/464/466)
The following features also apply equally to the CEL-460/462/464/466.
The CEL-460 series instruments are recommended for detailed measure-
ments as they feature extended processing and memory functions.
There is an additional 30-100 dB measurement range that can be used
for environmental surveys, and automatic run timing facilities controlled
Table 2: Setups and Configuration Files
Parameter settings that do not modify preset
measurement protocols can be changed by
using the instrument keys.
All available parameter settings can be changed
from a PC by means of dB10 or dB12 Software.
Parameter settings that modify preset
measurement protocols must first be saved by
dB10 or dB12 under a new setup identity in an
instrument "configuration file".
A "configuration file" contains a complete
instrument set of setups, i.e. up to seven dose
setups, one SLM setup, and one timer setup
common to all dose setups.
Parameter settings on an instrument can be
changed ONLY by using either dB10 or dB12 to
replace the configuration file in the instrument by
another configuration file loaded from the PC.
CEL-420/460 Getting Started - Page 55