Iwatsu SC7101 - Page 3

SC-7101 /SC-7102
Cautions on Operations
When using the Frequency Counter SC-7101/SC-
7102, take care on the following items.
Ambient Temperature and Ventilation
The instrument operate normally in the ambient
temperature of O°C to +40°C. Be sure to use
the instrument within this range. Use beyond
the limits of this range can result in some
trouble. Do not place anything near the venti-
lating hole in the cover to improve the efficiency
of heat dissipation.
Check the Supply Voltage
Before plugging the power cord to an electrical
output, be sure to check its voltage. The instru-
ment can be used on the line voltage shown in
Table 1, which can be selected with the voltage
selector plug on the rear panel. Operating the
instrument on other than the specified voltages
can result in breakdown.
In case of switching the voltage selector,
remove the power cord. Then remove the fuse
holder cap by turning it in the direction shown
by an arrow. Pull and remove the voltage selec-
tor, then insert into the desired center voltage
value.
Table 1
Center voltage Voltage range
AC 100 V 90 to 110 V
AC 120 V 108 to 132 V
AC 220 V 198 to 242 V
AC 240 V 216 to 264 Vv
Do Not Apply Excessive Voltage
The maximum allowable input voltage is 200
V (DC + peak AC). Never apply any voltage beyond
these voltages.
Connection of Input Signals
Use a supplied coaxial cable for connection
of input signals. Use of single core wires may
cause an incorrect measurement by electric noises
due to induction. When there is any fear of
mixing of noises, etc., check input signals with
the oscilloscope. Start measuring only after
confirming that there is no mixing of noise, etc.
di
Switch on the Rear Panel
The 10 MHz STD OUT-IN switch on the rear panel
is set to OUT side at the time of shipment.
When this switch is set to "IN" side, no signal
of the internal reference oscillator is connected.
Be sure to set this switch in "OUT", since setting
in "IN" will not allow measurement without apply-
ing external reference signal.
Earth a Protective Ground Terminal
When supplying the line voltage from the power
consent using a two-conductor type power cord,
ensure to connect the ground terminal on the
rear panel to the earth in order to prevent a
danger.
When supplying the line voltage from the power
consent using a supplied three-conductor type
power cord, grounding is provided with an earth-
ing wire attached to the power cord.
Type of Input Circuit
The input circuit of the instrument is not
of the floating type but the circuit type apply-
ing the unbalanced signal against the earth poten-
tial. Never perform measuring the primary power
source with an unclear earth potential, which
causing significant danger.
Ensure
to
Replace
a
Fuse
with
the
Requied
Rated
Current
0.3
A
fuse
is
used
in
the
instrument
in
order
to
prevent
the
damages
to
the
circuit
due
to
excessive
voltage.
If
it
is
fused,
make
sure
to
replace
only
fuse
with
the
required
rated
current
after
closely
checking
the
cause
of
fusing
and
repairing
the
defective
portion.
Never
use
those
fuses
other
than
the
rated,
as
it
may
result
in
failure
of
the
instrument.