Casella CEL CEL-63X - Manual (Page 77)

CEL-63x Environmental & Occupational Noise Meter
77 Casella CEL
9. Highest level
Using the microphones CEL-251 and CEL-252, the highest sound pressure level
that the CEL-63x instrument has been designed to measure is 140 dB. These
microphones have a nominal sensitivity of 50 mV/Pa.
The highest peak-to-peak voltage that can be applied safely to the pre-
amplifier‟s input through the CEL-516-2 line input adaptor is 28.5 V.
For high-range instruments using the CEL-259 ¼-inch high-range microphone
and CEL-259/A ½-inch to ¼-inch adaptor, the highest sound pressure level
that can be measured is 165 db.
10. Power supply voltage range
The CEL-63x instrument can be powered from three internally-fitted AA
batteries, or from an external 12 V DC supply through a 2.1 mm connector (tip
is positive). The instrument can also be powered from a 5 V DC supply through
a USB connection to a PC.
The DC supply range is 9 V to 14 V
The USB supply range is 4.5 V to 5.5 V
When operating from internal AA batteries, the battery voltage range must be
from 3 V to 5 V.
A battery condition symbol on the instrument‟s screen flashes a warning
when the battery voltage falls to 3.3 V or lower.
The instrument stops the current run and turns OFF when the batteries
have discharged to 3.0 V. This is to make certain the instrument does
not make data measurements that will not meet the requirements of
IEC 61672.
11. Display device
The display device displays the complete linear operating range.
12. Environmental stabilisation time
The typical time taken for the CEL-63x instrument to stabilise after sudden
changes in the environmental conditions is as follows:
5 minutes after a 10 °C change in temperature
5 minutes after a 30 % change in humidity (non-condensing)
15 seconds after a 5 kPa change in ambient pressure