Datron 4708 User Handbook Manual page 91

AC
Millivolts
Verification
(ImV
-
lOOmV
Full
Range
Values).
Summary
of Verification
Procedures
Method
1
At LF,
the
IV
Full
Range
value
is first
verified
using thermal
transfer,
then
this
voltage
is
divided via the standard
IVD
to
standardize an
AC
DMM
at
the millivolt Full
Range
value.
The 4708
millivolt
range
is
then
verified at this
standardized
value by
DMM
measurement.
See pages 7-18/19
for the
procedure.
At
HF,
the
4708
is
set to the
lOV
Range.
Outputs are
measured
at
lOV
and
IV
using thermal
transfer,
and
a
linearity correction factor
is
calculated for the
IV
output.
The
IV
Range
is
selected
with output
set to
lOOmV
at
HF.
The
output
setting
is
changed by
the correction factor
and
the
output
is
used
to
standardize the
AC DMM.
The
lOOmV
Range
is
selected
at
HF
Full
Range, and
the
output
measured on
the
DMM.
The
1
00m
V
Full
Range
value
verifies
if
the
DMM
reading
is
the corrected value, plus
or
minus
the specified tolerances.
The
DMM
is
standardized
at
10m
V
on
the
lOOmV
Range, and
used
to
verify the
lOmV
Full
Range
in the
same
way.
The
process
is
repealed to verify the
ImV
Range.
See pages 7-20
to
7-23
for
the procedure.
Method
2
At both
LF
and HF,
the
IV
Full
Range
value
is first
verified
using thermal
transfer,
then
this
voltage
is
divided
via
the
wideband
IVD
to
standardize an
AC
DMM
at
the millivolt
Full
Range
value.
The 4708
millivolt
range
is
then verified
at this
standardized value
by
DMM
measurement.
See Appendix 4
for the
procedure.
Interconnections
Interconnection
instructions in this
section arc necessarily
simple
and
basic,
and
are
mainly
intended
to
show
connec-
tions to the
4708.
It is
recognized
that
they
may
need
to
be
adapted
to
meet
an individual
user's
requirements.
It is
assumed
that users will
possess
knowledge
of
the
operation
and
use of standards
equipment such
as
lhatmentioned above.
Equipment Requirements
at
LF;
•
A
commercially-available Inductive Voltage Divider
tapped
at 10:1,
100:1
and 1000:1 of
suitable
accuracy
and frequency
response.
at
HF;
•
The 4708 under
test
with
the correction figure for
10%
of
its
lOV Range
at
HF.
•
The
DC
Voltage Source used
for
IV
-
1000 ranges
and
at
both
LF
and HF;
•
The
AC/DC
Thermal
Transfer
used
for
IV
-
lOOOV
ranges.
•
A
DMM
of
suitable
accuracy and frequency
response.
Example:
Datron 1281 or 1081.
Preparation
Before attempting any
verification
ensure
that
the follow-
ing steps
have been
carried out.
1
.
Turn on
the instrument
to
be checked and allow
at least
2 hours
warm-up
in the specified
environment.
2.
Cancel any
MODE
keys,
ensure
OUTPUT
is
OFF
and
check
that
'cal'
is
not present
on
the
MODE
display. (If
'cal'
is
present, turn the Calibration
Keyswitch on
the
Rear Panel
to
its
RUN
position).
3
.
Before connecting and
operating
any equipment,
consult the
manufacturers' handbooks.
4. Self-Test:
Press
the
'Test'
key
to
carry out the
test
routine described
in
Section
4.
Terminate
the
test
routine.
5. If
'Spec'
Mode
is
required, select either 24hr,
90dy
or
lyr on
the
Rear Panel
CALIBRATION INTERVAL
Switch.
When
received
from Datron,
90dy
is
the
relevant selection.
The
report sheets
hold
figures for
this interval.
7-16