Fluke 732a - Procedure A: Calibrate to Certified 732 A

732A
!
. Adjust
the
UUT
for
zero
on the Null
Detector.
2.
Reverse
the
HI and
LO
(positive
and
negative)
leads
on the
UUT
and RU
(Reference
Unit).
3.
Obsen'e
the
Nut!
Detector reading. If
the
reading
does
not
equal
zero, adjust
the
UUT
for
one-half
of
the
Null
Detector
reading.
4.
Reverse
the
HI
and
LO
(positive and
negative)
leads
on
the UUT
and
Certified
732
A.
The
Null
Detector
should
have the
same
reading
as
it did at
the
end
of
step
3.
If
not, adjust
the
UUT for
one^haif
the
difference,
5.
Repeat
steps 2
through
4
until the
Null
reading
does
not
change
when
the
UUT
and
Certified 732A
leads
are
reversed.
6>
The
residual
reading
on the
Null
Detector
equals
the sum of
the
thermal
voltages
in the circuit.
4»37.
Procedure
AiCallbrate
to
Certified 732A
4-38,
Complete the
following
procedure to standardize
the
outputs
of
the
732A to a Certified 732A.
Battery
operation
of
the
732A and
845AB/AR
is preferred.
Set
the N
uli
Detector to ZERO
when changing leads. Use the
supplied
adjustment
tool for all adjustments
(Fluke
P/N
6861
13).
1 .
Perform
the
self-calibration
procedure
on the
Precision
Divider
immediately
prior to this
procedure.
2.
Obtain
a certified 732A.
3.
Connect
the UUT
and
the
Certified
732A as
shown
in Figure
4-6.
4.
Set
OPR
switch
on
the Null
Detector
to the
ZERO
position,
then
switch power on. Adjust the
Null
Detector
for
zero
on the
3
range.
5-
Set
the
Null
Detector to the 30
mV
range and the
OPR
switch to
OPR.
6.
Decrease
the
range
setting on the Null Detector
slowly
while
adjusting
the
lOV calibration
potentiometer,
through
the front
panel opening
on
the UUT,
for a null
indication on the Null
Detector
on
the
3/iV
range.
Let
the system
stabilize
for
about
1
minute
before
adjustment.
Use the non-
conducting
adjustment
tool
supplied with
instrument.
7.
Verify
the null.
8.
Connect the
equipment as
shown
in Figure
4-7.
Set
the
Precision
Divider ratio
switches
to
0.999999X.
9.
Adjust
the
Adjustable
Source
for a null
indication,
10.
Verify the
null
! 1 ,
Connect
the
equipment
as
shown in Figure
4-
8.
Set
the
Precision
Divider ratio
switches to
0,1018000.
12.
Set
the
Null
Detector RANGE
switch to the
3
volt
range,
then
connect the Input lead
to the UUT
1.
018V
terminal.
Switch the
Null
Detector to OPR.
13.
Adjust
the
1.018V calibration
potentiometer
on the
UUT
while decreasing the
RANGE setting
on
the
Null
Detector
to
obtain a null on
the
3
/xV
range.
Use
the
non-conducting adjustment
tool.
CERTIFIED
732A
NULL
DETECTOR
UUT
Figure
4-6.
732A
Procedure
‘A’
10V
Calibration
4-9