Model 820 Technical Reference Manual
Taking a Measurement
5-5
unfiltered (A16, C16 and Flat do
not apply to the Model 820).
Step 4
The Model 820 has been preset at [A]. To change the
setting press
mr
to the preferred setting and
e
.
Step 5
Find item 41 by pressing
d
,
AC Out Weighting
,
which has the values listed here. Choose one by
pressing
r
.
[Flat, Whgt, F+20, W+20]
F+20 means Flat plus 20 dB of
level added.
W+20 means Weighted with 20 dB
of level added.
Step 6
Item 42,
UwPk Weighting
, press the
d
again. Chose
from the values listed with
r
.
[Flat, C]
Flat record all sound and C
weighting simulates the human
hearing at higher sound levels.
Step 7
Item 43,
Mic Polarization
, was touched upon earlier.
This selects the polarization volt-
age for the microphone. Choose 28
or 200 V (typically 200 V is cho-
sen) for condenser type micro-
phones and 0 V for pre-polarized
microphones (electret).
Step 8
Press
c
to exit setup mode.
L
max
-L
min
We have already looked at the L
max
and L
min
in a previous
screen. These values are also available directly from display
keys. They can be accessed while the unit is taking a measure-
ment or in the stop mode. Only when the unit is running is the
data recorded. These measurements are usually read after they
have been taken and the measurement is stopped. Here we will
examine them while a measurement is being taken:
Step 1
Press
V
to display the greatest RMS SPL value
since the beginning of the measurement:
The highest RMS level occurred at
9:19 hrs., and was 99.2 dBA on the
given date. Additional screens are
available here recording the num-
ber of times the current reading
has reached predetermined levels
(selected in parameters 61-62.
