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845AR
SECTION
li
OPERATING
INSTRUCTIONS
2-1.
RECEIVING INSPECTION
2-2.
This instrument has
been
thoroughly
tested
and
inspected before being shipped
from
the factory.
Im-
mediately upon receiving
the
instrument,
carefully
in-
spect
for
damage
which
may
have occurred
during
ship-
ment.
If
any
damage
is
noted, follow the instructions
outlined
in
the
warranty page
at the
back
of this
manual.
2-3.
CONTROLS, TERMINALS,
AND
INDICATOR
2-4.
The
location
and
function
of the
front-panel
controls
are described
in
Figure
2-1.
Detailed oper-
ating
descriptions are given
in
the following
para-
graphs.
2-5.
PRELIMINARY
OPERATION
2-6.
Connect
the
Model
845AR
line
plug
to
a
115
volt
ac
power
outlet
or
to
230
volts
ac
if
the
instrument
is
so
wired.
WARNING
1
.
The
round
pin
on
the
polarized three-prong
plug connects
the
instrument case
to
power
system
ground.
Use
a
three-to-two
pin
adapter
when
connecting
to
a two-contact
outlet.
For
personnel
safety,
connect
the
short lead
from
the
adapter
to
a high-quality
earth
ground.
METER
Indicates the
voltage
applied
to
the input terminals.
OPR
ZERO CONTROLS
ZERO
-
Opens
input
terminals
and
shorts
amplifier input
alio'
ing
zeroing
of
the instrument
with
the lower zero control.
OPR
-
Instrument
is
ready
for
operation
as
a
voltmeter
or
null
detector.
POWER
SWITCH
ON
-
Line
power
applied
to
instrument.
ISOLATED
OUTPUT
LEVEL
CONTROL
For full-scale
meter
deflection,
this
control
allows adjustment
of the
isolated
output voltage
from 0
to
1
volt
dc.
INPUT
AND
COMMON
TERMINALS
Provide
connection
to
vol-
tage being
measured.
.
POWER
LIGHT
Indicates
line
power
is
applied
to
the instrument.
'
T
*
m9
Mtamm
WWW-
GUARD
TERMINAL
This terminal
is
usually strapped
to
the
common
terminal
The
terminal
is
connected
directly
to
an
inner
chassis
shield.
By
removing
the
strap,
a
guard
potential equal
to
the
common
terminal potential
may
be
applied
to
the
guard
terminal, shunting the
leakage
current
from the
common
terminal
to
ground.
MECHANICAL ZERO
Screwdriver adjustment
usee
to set
the
meter
to
zero.
ISOLATED
OUTPUT
TERMINALS
Provide connection
to
an
external recorder.
RANGE CONTROL
Provides selection of the desired full-scale
sensitivity
Figure 2-1.
CONTROLS,
TERMINALS,
AND
INDICATOR
2-1
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