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GETTING STARTED
2.5 BASIC MEASUREMENT
TECHNIQUES
The following
paragraphs describe the basic procedure to
make basic measurements.
More detailed information
on
various aspects of Model 194 operation is located in Sec-
tion 3.
2.51 Warm Up Period
The Model 194 is usable immediately when it is first turned
on. However, the instrument
should be allowed to warm
up for at least one hour to achieve rated accuracy.
2.5.2 Input Connections
The VOLTAGE INPUT jack is intended for all signal inputs
to the instrument.
This jack is an isolated BNC connector,
with the outer shell connected to input low, and the center
connector
connected to input high.
WARNING
The maximum
common-mode
voltage
(voltage
between
input
low and chassis
ground)
is 30V
RMS,
42.4V
peak.
Exceeding
this
value
may
create
a shock
hazard.
CAUTION
The maximum
input
voltage
is
250V peak,
2 x
lO'V*Hz.
Exceeding
this
value
may
cause
damage
to the instrument.
NOTE
Shielded cable should be used for all input and
output connections
to minimize
the possibility
of
EMI radiation.
2.5.3 Fundamental
Control
Selection
Before making measurements
with your Model 194, you
will probably want to select the following operating modes,
as described below.
Step 1: Select the Channel
If your instrument
is equipped
with two A/D modules,
select the channel you wish to use by pressing the CHAN-
NEL button. The selected channel is displayed in the right
most digit of the display. A dual channel display mode is
also available with dual-channel
units.
2-14
Step 2: Set the Range
Press uprange or downrange
to select the measurement
range (32OmV, 3.W 32V, or ZOOV), or press AUTO and let
the instrument
choose the best range for the applied
signal.
Step 3: Program the Sampling
Rate
Press RATE followed by the desired data entry sequence.
For example, to program a 1Omsec sampling interval, press
the following
in order: RATE, 1, 0, ms. Press FREQiTIME
immediately
after RATE to change between time and fre-
quency units.
Step 4: Program the Number
of Samples
Press SAMPLES followed by the desired numeric keys. For
example, to program 1000 samples, press the following
in
order: SAMPLES, 1, 0, 0, 0, ENTER. Press FREQiTIME im-
mediately after SAMPLES to toggle between measurement
duration
and number of samples.
Step 5: Select a Trigger Source
Press SOURCE and then uprangeidownrange
repeatedly
to scroll through
available trigger sources: IMMEDIATE,
(TRIGGER
button),
INPUT
SIGNAL,
EXTERNAL,
OTHER CHANNEL.
Press CHANNEL
to return to the
normal display mode. (the trigger source is selected as
soon as it appears on the display).
Step 6: Choose the Single/Continuous
Trigger Arming
Mode
To arm the A/D converter (only once), press SGLKONT
until the SGL indicator is on. To automatically
re-arm the
A/D converter, press SGLKONT
until the CONT indicator
is on. Once the desired mode is selected, apply the ap-
propriate trigger, as selected by the SOURCE key, to begin
the measurement sequence or sequences (TRIGGER must
be pressed to arm the A/D converter for all modes except
immediate).
Step 7: Select Input
Coupling
Press the CPLG key to select the desired input coupling.
Ground coupling is in effect when both AC and DC are off.
Step 8: Choose Your Math Function
Press the desired math key. For example, to select the
average function,
press AVG. (If you are already in a mode
requiring
data entry, you must press SHIFT first.)
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