Fluke 893A Instruction Manual page 50

METER
INDICATION
JUMPER
WIRE
0 to ±0.
6
NONE
-0. 6 to -1.
8
B
- 1
.
8 to -3.
A
-3. 0
and above
BOTH
Figure
4-14.
JUMPER
WIRE SELECTION
f.
Adjust
A2R26
for
an exact zero-center
meter
indication,
g.
Reduce the calibration voltage
to
100
±0.
002%
volts
dc and place the
RANGE
switch to 100,
h.
With the
NULL
SENS
switch to
0. 01,
adjust
A3R14
for
an exact zero-center
meter
pointer indication,
i.
Reduce
the calibration voltage to 10 ±0,
002%
volts
dc
and place the
RANGE
switch
to
10.
j.
With
the
NULL
SENS
switch
to
.
001, adjust
A2R33
for
an exact center-zero
meter
pointer indication,
k.
Reduce
the calibration voltage to
1
±0.
002%
volts
dc
and place
the
RANGE
switch to
1.
l.
With
the
NULL
SENS
switch
to
.
001,
adjust
A2R35
for
an
exact
zero-center meter
pointer indication.
m. Reduce
the calibration voltage to
80
millivolts ±0.
1%
and place the
RANGE
switch to 100.
n.
Place
the
Readout
dials to 00. OSQ,
observing that a
zero-center
meter
indication
is
obtained within ±1/2
of
a
small division on
the
vernier
Readout
dial.
0
.
If
the
results
of
step n are not obtained, adjust the
vernier Readout
dial for
an exact
zero-center
meter
indication
and loosen
the set
screw
that
secures
the
vernier
dial
indicator
to the
potentiometer
shaft.
Refer to
Figure 4-15
for
location of
the set
screw.
MODEL
893AR
MODEL
893A
SET
Figure 4-15,
VERNIER DIAL
SET
SCREW LOCATION
4-55.
AC
CONVERTER
CALIBRATION
p.
Position the vernier
dial
indicator for a front
panel
indication of
80
and
securely tighten the set
screw.
4-56.
To
calibrate
the
AC
Converter, apply ac power
to the
instrument
and proceed
as follows:
q.
Remove
the calibration voltage
from
the
Model
893
and place a shorting
jumper between
the
LO
and HI
INPUT
terminals.
r.
Place
the
Model
893 controls as follows:
POWER
RANGE
NULL
SENS
MODE
Readout
dials
ON/LINE
OPR
10
.
001
+
00.
000
s.
Rotate the vernier Readout
dial until
a full-scale
(-1)
meter
pointer indication
is
obtained,
observing
that the
vernier Readout
dial
indication
is
between
9
and
11.
a.
Place
the
Model
893 controls as follows:
POWER
RANGE
NULL
SENS
MODE
Readout
dials
ON/LINE
OPR
100
0.
AC
100.
00
b.
Apply
a calibrated 100
volts
ac signal
at
400
Hz
between
the
HIGH
and
LD INPUT
terminals and ad-
just
A7R31
for a
meter
indication
of
zero-center
±1/2
major
division.
c.
Apply
a calibrated 100
volt
ac signal
at
50
kHz
between
the
HI and
LO
INPUT
terminals and
adjust
the
stray capacity
compensator
slightly,
using
4-16
9/22/71
893A