Combined Calibration And Performance Tests; General - HP 3478A Technical Manual

3478A
10 ohm ± .0005%; (Guideline Model 9330/10 or
9330//10)
100 ohm ± .0005%; (Guildline Model 9330/100 or
330A/100)
1K ohm ± .0005%; (Guildline Model 9330/IK or
9330A/ 1K)
10K ohm ± .001%; (Guildline Model 9330/10K or
9330A/IK)
100K ohm ± .001%; (Guildline Model 9330/lOO1K or
9330A/100K)
1M ohm ± .002%; (Guildline Model 9330/IM)
10M ohm ± .01%; (Guildline Model 9330/IOM)
4-75. Test Procedure.
Volts Tests have been done, before doing the Ohms
Test. Also make sure the 3478A has been warmed up
for at least one hour, then do the following:
a. (Step #1.) Reset the 3478A by pressing the blue
Shift button and then the SGL/TRIG (TEST/RESET)
button.
b. (Step #2.) Set the 3478A to the desired Ohms
Function (see paragraph 4-70).
Function is to be tested, short the HI and LO INPUT
Terminals. If the 4-Wire'Ohms Function is to be tested,
short the SENSE Terminals and the INPUT Terminals,
as shown in Figure 4-6.
3478A's display and record the reading on the Test Card.
Figure 4-6. 4-Wire Ohms Short
c. (Step #3, 4, 5, 6, 7, and 8.) Set the 3478A to the
3001, 3K1], 3Knl, 300Knl, 3Mn, and 30M1l Range by
pressing the Uprange button once for each range.
Record and make sure the reading on each range are
within the specified limits. If any readings in this step
and step b are out of the specified limits, go to the Ohms
Calibration Procedure in paragraph 4-103.
d. (step #9.) Remove the short from the 3478A's
INPUT Terminals and set the multimeter to the 300
Range.
e. Connect either a 3012 or 101f Standard Resistor to
the INPUT Terminals (refer to paragraph 4-71 to
Make sure the 3478A's DC
If the 2-Wire Ohms
Check the reading on the
determine the resistor value).
tested in the 2-Wire Ohms Function, connect the resistor
to the HI and LO INPUT Terminals. If the test is to be
done in the 4-Wire Ohms Function, connect the resistor
as shown in Figure 4-7.
Figure 4-7. 4-Wire Ohms Connection
f. Check and record the reading.
g. (Step #10 through 15.) Check the 3478A's 30012,
3KΩ, 30KΩ, 300KΩ, 3MΩ, and 30MΩ Ranges by
connecting the following standard resistors to the
multimeter's input: 300Ω (or 100Ω), 3KΩ (or 1KΩ),
30KΩ) (or 10KΩ), 300KΩ (or 100KΩ), 3MΩ (or 1MΩ),
and 30MΩ (or 10MΩ), respectively. Check and record
the readings.
h. Remove the Standard Resistors from the 3478A.
This completes the Ohms Test.
calibrating the instrument (go to paragraph 4-103). If the
test still fails, go to this manual's Section VII for
troubleshooting.
4-76. COMBINED
PERFORMANCE TESTS

4-77. General

4-78. The following paragraphs have the 3478A's
Combined Calibration Procedures and Performance
Tests. The Performance Tests are included in the
procedures since they are normally performed after
calibration. The procedures are set up in such a way
that the Performance Tests can be ignored, if so desired.
4-79. Since the 3478A has no internal adjustments, the
multimeter is calibrated electronically.
calibration source is applied to the 3478A's INPUT
Terminals which is used to calibrate the multimeter. Ten
readings are then taken and the entered value of the
calibration source is compared with the average value of
the ten readings. A Calibration Con-
4-11
TM 11-6625-3071-14
If the 3478A is to be
If any test fails, try
CALIBRATION AND
A known good