5-4
Taking a Measurement
Model 820 Technical Reference Manual
Step 8
The property controlling the final screen in this
series is built into the Model 820 to conserve power.
Press the
d
key.
The Model 820 has been pro-
grammed to save power whenever
it can. Each time input is made the
internal timer will start at 100 and
count downward. If not pro-
grammed to do otherwise, the
Model 820 will turn itself off when
this screen reaches 0, just over two
minutes.
Pressing the
d
key again will
scroll loop you back to the SLM
original screen.
Now that you are more familiar with the information available
in the displays above, lets take a closer look at the parameters
that affect these readings.
Step 1
To access these parameters turn the Model 820 on by
pressing
c
. Next press
R m 3 9
e
(Or press
R
,
C
), and the following
screen will appear:
Slow: exponential avg.: 1 second
constant.
Fast: exponential avg.: 1/8 second
constant.
Impl: impulse response.
For OSHA measurements, this is
normally set to Slow. For environ-
mental measurements, Fast or
Slow may be used. Within a given
period of time, the Fast detector
will take more measurements than
the Slow. Therefore, the Fast
detector is likely to measure more
higher and lower levels than the
Slow detector.
Step 2
The Detector prompt has three possibilities indi-
cated above. Press
mr
to access desired set-
ting, and
e
Step 3
To set the
Frequency Weighting
, press
d
to item
40. There are several possibilities here:
[A, A16, C, C16, Flt]
The A and C weightings simulate
human hearing response and meet
Type 1 precision standards for
accuracy. Flat (no weighting)
allows the signal to pass through
0
