TM 11-6625-444-14-1
+
m. Ratio Alignment. Perform alignment
and EXTERNAL REFERENCE terminals of the
operations as follows:
voltmeter.
( 1 6 ) Adjust the 10V COMMON MODE
(1) On the voltmeter, set the FUNCTION
switches to VDC and FILT and set the RANGE
control (A3R11) to obtain a reading of +7.0000
switch to 10.
VDC on the differential voltmeter, and a digital
(2) Connect a shorting jumper between the
readout of 100.0070 2 digits on the voltmeter.
INPUT terminals.
(17) Reduce the input voltage to the INPUT
and EXTERNAL REFERENCE terminals to
(3) If necessary, adjust the front panel DC
-1.0000V and adjust the ZERO OFFSET control
ZERO control to obtain a readout of 00.0000.
(A3R3) for a digital readout of 100.000% on the
(4) On the voltmeter, set the FUNCTION
voltmeter.
switches to VDC and RATIO, set the
(18) Increase the input voltage to the IN-
RANGE switch to 10, turn the SAMPLE RATE
PUT and EXTERNAL REFERENCE terminals
control fully clockwise, turn the RATIO FULL
SCALE control to midposition, and turn the
to -10.0000 VDC. The voltmeter digital readout
should be 100.000% 5 digits.
RANGE LEVEL control (A3R50 located through
the guard covers) to the fully counterclockwise
(19) If step (18) fails to yield 100.000% 5
position.
digits, repeat steps (16) and (17) until a setting
for the ZERO OFFSET control (A3R3) is found
(5) Connect a shorting jumper between the
that will produce a digital readout of 100.0009'0
rear panel INPUT terminals, and connect a
for - 1.0000 VDC and 100.00% 5 digits for
jumper between the rear panel EXTERNAL
-10.0000 VDC applied to the INPUT and EX-
REFERENCE input terminals.
TERNAL REFERENCE terminals.
(6) Connect the low terminal of a differential
(20) Apply -100.000 VDC to the EX-
voltmeter to the LO SENSE (A9TP7) test point
TERNAL REFERENCE terminals.
on the voltmeter, and the high terminal to the
(21) Connect a shorting jumper across the
HIGH SENSE (A9TP5) test point.
INPUT terminals.
( 7 ) Adjust the ZERO OFFSET control
(22) Connect the low side of a differential
(A3R22) to obtain a reading of 500 microvolt
voltmeter to A9TP7 and the high side to A9TP5.
on the differential voltmeter.
(23) Adjust the 100V CAL control (A3R6) to
(8) Remove the shorting jumper from the
rear panel EXTERNAL REFERENCE input
obtain a reading in the range of +6.999975 and
7.000025 volts on the differential voltmeter.
terminals and apply -- 10.0000 VDC. (Leave the
INPUT terminals shorted.)
(24) On the voltmeter, select the 100V range.
(9) Null the differential voltmeter.
(25) Apply -100 VDC to the INPUT and
( 1 0 ) Adjust the RATIO FULL SCALE
EXTERNAL REFERENCE terminals.
control to fully clockwise and note the reading on
(26) Adjust the 100V COMMON MODE
the differential voltmeter.
control (A3R8) to obtain a reading in the range of
(11) Set the RATIO FULL SCALE control
+6.999975 to 7.000025 VDC on the differential
to fully counterclockwise and note the reading on
voltmeter.
the differential voltmeter.
(27) Apply -10.600 VDC to the INPUT and
(12) Set the RATIO FULL SCALE control
EXTERNAL REFERENCE terminals. Insure
to obtain a differential voltmeter reading halfway
that the 100V range switch is depressed.
between those noted in steps (10) and (11).
(28) Set the RANGE LEVEL control
(13) Adjust the 10V CAL control (A3R3) to
(A3R50) to its fully counterclockwise position.
obtain a reading in the range of +6.999925 and
( 2 9 ) Adjust the RATIO FULL SCALE
+7.000025 VDC on the differential voltmeter.
control to obtain a digital display of 100.000% on
(14) Remove the shorting jumper from
the voltmeter.
across the INPUT terminals.
(30) Slowly turn t h e R A N G E L E V E L
(15) Apply -10.0000 VDC to the INPUT
