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Sect.
tr
Page
2
CHECK
-
The instrument
is
sel-f-checking
when
the
sxirr'h
Ls
in ll)e CHECK
posrtron.
FREQI./ENCY
UNII
This switch determines the length
ol time in
seconds
that
the
gate
is
open
during frequency ureasuren)ents.
The
frequency units are indicated
above
the
knob.
DISPLAY TIME
This control varies
the
time that the
count
is dis-
played. The minimum
display time obtainable
is
.
1
second
or
the
€iate
time.
whichever
is Iarger.
The
maximunl time
is
10
seconds
unless the
control is
slvitched to
oo in which
case
the count
is displayed
indefinitely.
when the
control is irl theod
position,
the count
is displayed until
the counting cycle
is
staded again
by
depressing the RESET button.
RESET
when
t}lis
button
is depressed, the counters
are re-
turned
to zero
and
a new
counting
cycle
is
ready to
stafi.
FUSE
The
fuseholder,
Iocated
on
the c(xrtrol
panel, contains
a
3.2
ampere
caftridge fuse. For
230
volt operation
the fuse should have a
rating of 1.6 amperes.
Re-
placement
fuses must
be
of the "SIo-81o" type
as
specilied in the Table of Replaceable Parts in this
instruction
manual.
POWER ON
This switch controls aII thc power supplied to the
j.n-
strument.
MANUAL GATE
.fhis
switch
opens
ard
closes the gate
when
the FUNC-
TION SELECTOR
switch
is
in
the MANUAL
GATE
position. In other positions
of
the function switch,
the MANUAL GATE switch in the OpEN position
prevents the stop pulse
from
closing the gate.
INPUT
This connector is
the
input terminal.
for Irequency
and
period measurements. During TIME INTERVAL,
MAMJAL
GATE,
and
CIiECK functions
this
connector
is
grounded
t-hrough
ttre input coupling network.
EXT.
This connector is the input
terminal for
any
external
time unit
and
is
connected
in place of the internal
time
unil
when
UqTIME
UNm
swilch is in lhe
EXT.
posrtron.
POWER
CABLE
The three-conductor power cable
on
the 5228
is
terminated
in
a
polarized
three-prong male connector
recommended by the
National
Electric
ManuJacturers'
Association. The
thid
contact
is
arl
ollset
round
pin,
added
to
a
starrlard two-blade
a-c plug, which
gr.ounds
the
instrument chassis
ivhen
used
with the
appropliate
receptacle. To
use
this
NEMA plug in a standard
two-contact
outlet.
it is
recommended
that
instead
of breaking off the
ground
terrrlinal,
a 2-prong to
3-prong adapter
be
used. The ground
connection
emerges
from the
adapter as a
short
lead which
should be connected
to
ground
for
the
protection
of
operating personnel.
COUNTER OUTPUT
The output of the
last
counter
is
available at this
terminal,
located
on
the
back
of
the chassis.
PHOTOTUBE VOLTAGE
A
+90
1,olt
polarizing voltage is available
at
the rear
of
the instrument.
It
has an
internal
impedance of
approximately
100,
000 ohms.
STD.
OUTPUT
Internally-generated standard frequencies are
avail-
able at
this
connector, These irequencies are
the
STD.
FREQUENCY COUNTED and
are
selected
by
means
oI the
TIME UNIT switch.
2-2
OPERAIION
It
should
be
kept
in mind while
using
the Model
5228
that
this instrument measures, basically,
frequency
or time.
There are two basic time measurements
that
can be
performed, period
and
time interval.
Period measures the time
between
two consecutive
points
on a
single
waveform. Time
interval
measures
the
time
between
two separate waveforms.
This irstrument requires
a
warm-up period
ol at
least
30
minutes
beiore
tie
specified accuracy
is
obtained
from the crystal. Less accurate
measurements may
be
made
alter
a
30
second
warm-up,.and the sensi-
tivity will
be
approximately L/2 volt at this time.
Before making any measurements
with this instru-
ment,
it
is desirallle to
check
the performance of
the instrument by
means
of the
built-in
checking
circuit.
This is
done as
follows:
a.
Set
the FUNCTiON
SELECTOR
switch to
the
CHECK
position
and
the
FREQUENCY UNIT
sv/itch
to
1
SEC.
b.
Set
the
DISPLAY TIME control
fullv
counter-
clockwise,
c.
II
all the
counters
display
zero at the
end
ol the
count. then t}Ie
instrument is periorming prop-
erly.
If
Uris count
is
not
displayed,
refer
to the
Main-
tenance
section
lor
probable causes and remedies.
The
procedure
for
operating the Model 5228
is
as
follows:
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