Datron 4708 User Handbook Manual page 37

causing 'Error 8
'
and buzzer
to
sound). Half-size zeroes on
the
Zero
display
show which keys
cannot be
used
to
increment from
Zero;
full-size zeroes
show
those
which
can.
When
the display
is
correctly incremented with
OUTPUT
ON,
the output terminals are
internally
reconnected
to
the voltage
output
circuitry.
Zero
Displays
Range
Zero
Display
ImV
.0oo,o
mV
lOmV
0.ooo,o
mV
lOOmV
0o.ooo,o
mV
IV
.0oo,ooo
V
lOV
0.ooo,oo
V
lOOV
0o.ooo,o
V
lOOOV Ooo.ooo
V
Output Voltage
Selection
There
are
two
overlapping
AC
voltage
states.
The 15V
overlap
allows
some
adjustment without changing
state.
60V 75V
1 1
Low
voltage
state
ge
state
In the
Low
Voltage
state,
the output can be switched
ON
directly,
but
deliberate user-actions are required
to transfer
from
Low
to
High
Voltage
state.
N.B.
The 4708
switches
its
output voltage
OFF
each time
the
lOOOV
RANGE
is
selected.
Low
Voltage Selections (up
to
75V RMS).
Using the
general sequence:
At
operation
(3)
;
Select
AC
At
operations
(4)
and
(5)
:
No
Remote
Sense on Im,
10m
and 100m
ranges.
High Voltage
selections (above
75V RMS).
Using the general sequence:
At
operation
(3)
:
Select
AC
At
operation
(9)
:
OUTPUT RANGE
LED
flashes for selections
above
75
V
RMS.
At
operation (II)
:
Audible warning
- 5
pulses/sec for 3
secs.
After 3
sec.
warning
:
4708
sets
OUTPUT
ON.
While
OUTPUT
is
ON
:
Audible reminder
pulses continue
at
approx.
1
sec. intervals,
and
RANGE
LED
continues
flashing.
If
OUTPUT OFF OR ON
switching
is
attempted during
the 3
sec.
delay the
4708
reverts to
OUTPUT
OFF.
OUTPUT ON
Transfers
If
OUTPUT
is
already switched
ON
in
Low
Voltage
State
when
an
attempt
is
made
to select
a
voltage in
excess of 75
V RMS
,
the
4708
safety interlocks
prevent
the selection. Certain
deliberate
actions, detailed
below, are then required by
the operator
to
effect the
selection.
Transfer from
Low
into
High Voltage
State,
by manual
upranging:
-
4708
switches
OUTPUT
OFF,
-
Selected
RANGE
LED
flashes.
Operator
reselects
OUTPUT
ON:
- 3 sec
audible
warning
-
4708
switches
OUTPUT ON
-
Audible reminder while
OUTPUT
is
ON
-
RANGE
LED
continues flashing
-
OUTPUT ON
LED
lit
continuously.
Transfer from
Low
Into
High Voltage
State,
by
incrementing the
OUTPUT
display:
-
OUTPUT
remains
ON
at
previous voltage
-
OUTPUT
display
shows
selected
value
-
RANGE
and
OUTPUT ON
LEDs
flash.
Operator
reselects
OUTPUT
ON:
-
3 sec
audible
warning
-
4708
increases output voltage
to the
OUTPUT
display
value
-
Audible reminder
while
OUTPUT
is
ON
-RANGE
LED
flashing
-
OUTPUT ON
LED
lit
continuously.
Transfer from High
into
Low
Voltage
State,
by
pressing
OUTPUT OFF
key:
-
ON
LED
remains
lit
until
the output voltage has
decayed
(approx.
1
sec
from
IkV).
Transfer from High
into
Low
Voltage
State,
by
decrementing
the
OUTPUT
display,
or
by manual
downranging:
-
Transfer
to
Low
Voltage
State
is
automatic
when
the
Output Voltage
falls
below
60V
RMS.
-
RANGE
LED
stops flashing
- stays
lit
-
OUTPUT ON
LED
stays
lit
-
Audible reminder
is
silent
Changing
Voltage
State
when
in
Error
Mode
For
safety reasons, the thresholds are always
defined with
respect to the voltage at the output
terminals.
When
the
instrument
is
in
Error mode
the displayed output voltage
is
modified
by
the gain
error,
so
the threshold indications
may
not
coincide exactly with
75V
and
60V
on
the
OUTPUT
display.
4-8