Section 2
-485
/
R485
Service
OPERATING
INFORMATION
General
To effectively use the
485,
the operation
and
capabilities
of
the
instrument
must
be known. This section describes
the
operation
of
the
controls
and connections
and
gives
first-time and general operating information.
PRELIMINARY
INF
ORMAT
ION
Operating Vo
lt
age
WARNING
I
This instrument is designed
for
operation from a
power
source
with
its
neutral
at
or
near earth
(ground)
potential
wi
th a separate safety-earth
conductor.
It
is
not
intended
for
operation from two
phases
of
a multi-phase system,
or
across the
legs
of
a
single-phase, three-wire system.
The
485
can
be
operated
from
either
a
115
V or
230
V
nominal line voltage source,
or
a
220
V external
battery
pack. The Line Voltage Selector switch
on
the rear panel
converts this
instrument
from
one
operating voltage
to
the
other.
Power Cord Conductor Identification
Conductor Color
Alternat
e Color
Ungrounded (Line) Brown Black
Grounded (Neutral) Blue
Wh
i
te
Grounding (Earthing) Green-Yellow Green-Yellow
~
This instrument
may
be damaged
if
operated
with
the
Line
Voltage Selec
tor
switch set
to
incorrect posi-
tions
for
the line voltage applied.
115 V
230
V 90-136 V
180-272 V
The
485
is
designed
to
be
used with a three-wire AC
power system.
If
the t
hr
ee
to
two-wire
adapter
is
used
to
connect this
instrument
to
a two-wire AC power system, be
sure
to
connect
the ground lead
of
the
adapter
to
eart
h
(ground). Failure
to
complete
the ground system may allow
,he chassis
of
this
instrument
to
be elevated
abo
ve ground
potential and pose a sh
oc
k ha
za
r
d.
REV
. C,
MAR.
1977
Operating Temperature
The
485
can
be
operated
where
the
ambient air
temperature
is
between
-15
°C
and
+55
°C (+5° F
and
+131°F). This instrument
can
be stored in ambient
temperatures between
-55°C
and
+75°C
(-67
° F
and
+
167
°F). A
fter
sto
ra
ge
at
temperatures
beyond
the
opera-
ting
li
mits, allow
the
chassis t
emperatu
re
to
come
within
the
operating limits before power
is
applied.
The
485
is
cooled by
air
entering through the air filter
on
the
rear panel and exiting through
the
holes
on
the
sides.
Adequate clearance must be provided
at
these locations.
Allow
at
l
east
one
inch clearance behind
the
air
fi
l
ter
and
at
least
one
inch
on
the sides.
A thermal
cutout
in this instrument provides thermal
protection and disconnects
the
power
to
the
instrument if
the internal
temperature
exceeds a safe operating level.
Power
is
automatically re
stored
when
the
temperature
returns
to
a safe level. Clean
the
air
filter periodically; a
di
rt
y filter prevents adequate air flow
into
the instrument.
CONTROLS AND CONNECTORS
General
The
major controls
and
connectors
for
operation
of
the
485
are
locat
ed
on
the
front
panel
of
the instrument. Some
auxiliary functions are provided
on
th
e side,
top,
bottom
an
d rear panel. To make full use
of
the capabilities
of
this
instrument,
the
operator
should
be familiar with the
function and use
of
each of these
contro
ls
and
connectors.
A brief descrip
tion
of
each
contro
l and
connecto
r
is
given
here.
Front
Panel
POWER Pushb
utton
Turns
instrument
on
or
off.
CAL 5 V Connector BNC
connector
for square-wave
voltage calibrator
output
signal.
FREQ
Pushbutton
Selects
one
of
two
frequencies
(1
kHz
or
1 MHz) for
the
fast-rise
calibr
ator
signal.
INTENSITY
Cont
rol Controls intensity
of
writing beam.
B INTENSITY Provides additional intensity
con
•
Control trol
fo
r
the
B SWEEP.
2-1
