Casella CEL CEL-393 - Manual (Page 19)

4. DESCRIPTION OF THE INSTRUMENT
4.1 Controls, Connectors and Display
Figure 3 shows the location of the various controls, connectors, and the
display, whilst set out below are the functions of the various switches.
This chapter can be taken as a shortform instruction set, and should allow
those familiar with advanced acoustic instruments to operate the instru-
ment successfully. For those who are less familiar, Chapter 6 contains
sample operations in the four operating modes.
FILTERS Switches
Lin - A - POWER OFF
When this switch is in the POWER OFF position, no power is drawn from
the batteries nor are any functions performed. The instrument operates
with the switch set to either of the other positions, A or Linear (Flat)
frequency characteristic, with the selected frequency weighting indicated
on the display (see Figure 4).
Frequency weightings are in series with the filter functions, allowing
A-weighted spectra to be produced if required. It should also be realised
that the current period answer calculation, and any results stored in the
memory are reset when this switch is moved between the A and Lin
positions.
At switch on, the instrument will indicate the battery voltage for approxi-
mately 20 seconds, and then revert to its default set of conditions. These
default conditions are described in Chapter 6.
Off - 1:1 - 1:3
This switch functions only on B and D versions of the instrument, and
must be left in the Off position on A and C versions.
393 Handbook /15.