TM 11-6625-444-14-2
from the second dc voltage calibrator.
(2) Apply a +1.8000 Vdc signal to the volt-
meter front panel HI and LO INPUT terminals
from the second dc voltage calibrator (A1).
(3) Adjust A1-R404 until the voltage moni-
tored by the digital multimeter at A1-U402, pin
12 just trips from approximately +5.0 Vdc to
FULL RANGE control for a display reading of
-15.0 Vdc.
+180.000 ( 20 counts).
(4) Check for proper trip point operation by
NOTE
first, reducing the front panel INPUT signal to
-1.7000 Vdc and observing that the digital multi-
For the balance of Dc Ratio Auto-
meter measures approximately +5.0 Vdc; and
ranging adjustments do not disturb
second, increasing the front panel INPUT signal
the setting of the RATlO FULL
to -1.9000 Vdc and observing that the digital
RANGE control.
multimeter measures approximately -15.0 Vdc.
b. Ratio > +180000 Up Range Trip Point
(1) Connect the equipment as shown in
d. Ratio < +14000 Down Range Trip Point Ad-
justment (A1-R400)
(2) Apply a +1.000 Vdc signal to the EX-
(1) Continue with the same setup as in the
TERNAL REFERENCE V and LO terminals on the
previous step.
voltmeter rear panel from the first dc voltage
calibrator (Al).
(2) Change the digital multimeter (A5) V-
test lead to monitor the signal at A1-U401, pin
(3) Reduce the voltage applied to the volt-
10.
meter front panel INPUT terminals to +1.7000
Vdc.
(3) Apply a +0.1400 Vdc signal to the volt-
meter front panel INPUT terminals from the sec-
(4) Observe that the voltage monitored by
ond dc voltage calibrator.
the digital multimeter is approximately +5.0 Vdc.
(4) Adjust A1-R400 until the voltage mea-
(5) Increase the voltage applied to the
sured by the digital multi meter at A1-U401, pin
voltmeter front panel INPUT terminals to +1.9000
10 just trips from approximately -15.0 Vdc to
Vdc.
approximately +5.0 Vdc.
(6) Observe that the voltage monitored by
(5) Increase the voltage applied to the
the digital multi meter is approximately -15.0
voltmeter front panel INPUT terminals to +0.1500
Vdc.
Vdc.
c. Ratio > -180000 Up Range Trip Point Ad-
(6) Observe that the voltage measured by
justment (A1-R404)
t h e digital multimeter is approximately -15.0
Vdc.
(1) Apply a +1.000 Vdc signal to the EX-
TERNAL REFERENCE V and LO terminals on the
(7) Reduce the voltage applied to the volt-
voltmeter rear panel from the first dc voltage
meter front panel INPUT terminals to +0.1300
calibrator.
Vdc.
(2) Apply a -1.8000 Vdc signal to the volt-
(8) Observe that the voltage measured by
meter front panel HI and LO INPUT terminals
the digital multimeter is approximately +5.0 Vdc.
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