Casella CEL CEL-393 - Manual (Page 68)

Measure traffic noise by a building near a main road using an L 10 (18
hour) index. This is the arithmetical average of 18 one hourl L 10 indices
between 6.00 am and 12.00 midnight, (defined in the relevant docu-
ments).
It is required to measure continuously for a period of 18 hours, which is
just within the instrument's operational capability with a new alkaline
manganese battery. However, it will be necessary to set the instrument
up, make the measurements, and retrieve all the relevant information
from store within the nominal 18 hour life of the battery.
As in practice this period will probably be deemed insufficient, the B and
D versions of the instrument can be powered from the CEL-238, CEL-338
or CEL-438 Processor/Printer, which itself may be powered from the
mains. All versions of the sound level meter may also be powered directly
from the mains using the CEL-3732/2 Power Supply as detailed below.
Either method will allow the CEL-393 to be set up the evening before the
measurements are to be made.
Use the CEL-2962 Windshield where measurements are to be made
outside, and a microphone extension cable to ensure that the instrument
can be installed in a secure location indoors if possible.
Proceed as follows.
1. Remove the internal battery from the CEL-393 to prevent
damage when it is to be powered by the the Secondary Proc-
essor or by the CEL-3732/2 Power Supply.
2. If the CEL-238, CEL-338, or CEL-438 is used, follow the con-
nection and setting up instructions in its handbook, and in the
operating instructions for the CEL-4566 Program Card.
3. If the Power Supply is used, set its switch to the CEL-160 (7.5V)
position, and connect it to the sound level meter using the
C4177 Cable.
/64. 393 Handbook