Datron 1061 Calibration And Servicing Handbook page 67

56
Set
up
DC-DC
Turnover
13.
Select
lV
range,
AC
+
DC.
Apply 'lV
500H2
and
perform GAIN
autocal.
14'
Apply +1V
DC
and note
the displayed reading'
15.
Apply
-1V
DC
and adjust R62
(DC
turnover)
for
the
same reading
as
in operation (14).
(t3
digits).
16.
Repeat (131
to
(15)
until all readings are
the
same
to
within
*20
digits.
Set
up
Coarse Frequency
Response
17.
Select 100V range, AC; apply 100V. 500H2
and
perform GAIN
autocal.
Apply 100V, 50kHz
and
adjust C82
for
a
display reading
of
100.000V
f20
digits.
(lf
necessary
change C81
to
a
value which
permits this adjustment).
18.
Apply
100V,
100kHz and note
the
reading
error'
Adjust C79
to
give
5
times
the error in the
same
direction.
19.
Repeat
(17) and (18) until the 50kHz and
100kHz
readings
are
separated
by
less
than 20
digits.
20.
Select
1V
range,
AC; apply
1V, 500H2 and perform
GAIN
autocal.
Apply 1V,50kHz
and
adjust
C84
for
a
display reading
of
1.00000V
*20
digits.
(lf
necessary
change
C85 to
a
value which
permits this adjustment).
Set
up
Crest
Factor
21.
Apply
'lVRMS,
+ve
5:1
Crest Factor signal. Adjust
R61
(crest
factor)
for
a display reading
of
1.00000V
430
digits.
22.
Apply
1VRMS,
-ve 5:1
Crest
Factor signal.
Check
that
display reading is 1.00000V
t30
digits.
23.
Apply
1
V,
500H2, and
perf
orm GAIN
Autocal.
Repeat (211,
l22l and
(23)
unt¡l
crest
factor
readings
are
within
limits.
Linearity
Checks
24. Select
lV
range, AC +
Dc. Apply
1V
DC
and
perform
GAIN
Autocal.
25.
Apply
1.9V
DC and
adjust R27
value
(Factory
Selected
Value
-
FSV)
for
a
display
reading
of
1.90000V
16 digits
(reducing
R27
increases readingl.
26.
Repeat
(24) and (25)
until
both
correct.
27
Select
1V
range
AC. Apply
in
turn 1V,
t00mV,
10mV,
at
500H2
and check
that display
readíng
is
correct
to within
t10
digits
of
the input voltage.
28.
Apply
open
circuit input,
set CAL/RUN switch
to
RUN; press 'Test'
and check
for
a
display
of
'PASS'.
Output Buffer
Check
29.
Select
1V
range,
AC + DC, no filter. Apply 1V
DC and
set CAL switch
to
RUN.
Use
the
'A-B'
computation
mode
to
null out the
reading:
press
STORE, B, then
(A-B).
30.
Select
filter.
and leave
to
settle
for
at least
30
seconds.
Check
that the
displayed
reading is
within *50
digits
of zero.
L{Þ
31.
Repeat
(28).
The AC set-up
procedure
is
now complete.
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