HP 3478A Technical Manual Download

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TM 11-6625-3071-14

SECTION IV

PERFORMANCE TEST AND CALIBRATION

4-1. INTRODUCTION

4-2. This section of the manual has the Performance
Tests and Calibration Procedures used to verify the
3478A’s accuracy specifications, and to calibrate the
multimeter to those specifications. A summary of the
specifications to which the 3478A is tested and calibrated
is listed in Table 4-1. The complete specifications are in
Table 1-1. All tests and calibrations are made without
removing any instrument ’covers.

4-3. Since Performance Tests are normally performed
after calibration, the tests are included in the Calibration
Procedures. The procedures are set up in such a way
that the Performance Tests can be ignored, if so desired.

Table 4-1. Abbreviated Specifications Table

DC Volts Function (accuracy =

(% of reading - number of counts))

Range 24 Hour Limits 90 Day Limit 1 Year Limits

30mV 0.027 + 35 0.03 + 41 0.04 + 41

300mV 0.005 + 4 0.0074 + 5 0.02 + 5

3V 0.0034 + 2 0.0059 + 2 0.0188 + 2

30V 0.005 + 3 0.0074 + 3 0.02 + 3

300V 0.0055 + 2 0.0076 + 2 0.02 + 2

DC Carrot Function (accuracy =

(% of r number of counts)

Range 90 Day Limits 1 Year Limits

300mA 0 11 + 40 0.15 + 40

3A<1A 0.14 + 6 0.17 + 6
3A>1A 1.0 + 30 1 0 + 30

Ohms Function (accuracy =

(% of r number of counts)

Range 24 Hour Limits 90 Day Limits 1 Year Limits

30 0.023 + 35 0.0027 + 41 0.034 + 41

300 0.0045 + 4 0.012 + 5 0.017 + 5

3K 0.0035 + 2 0.011 + 2 0.016 + 2

30K 0.0035 + 2 0.011 + 2 0.016 + 2

300K 0.0035 + 2 0.011 + 2 0.016 + 2

3M 0.0052 + 2 0.011 + 2 0.016 + 2

30M 0.036 + 2 0.066 + 2 0.078 + 2

AC Volt Function 1 Year Limits (accuracy =

(% of r number of

counts)

Frequency 300 mV Range 3V Range 30V Range 300V Range

20Hz 50Hz 1.14 + 163 1.14 + 102 1.14 + 102 1.18 + 102

50Hz 100Hz 0.46 + 163 0.46 + 103 0 46 + 102 0.5 + 102

100Hz 20KHz 0.29 + 163 0.26 + 102 0.26 +102 0.33 + 102

20KHz 50KHz 0.56 + 247 0.41 + 180 0.37 + 180 0.56 + 180

50KHz 100KHz 1.74 + 882 1.05 + 825 0.84 + 825 1.26 + 825
100KHz 300KHz N/A 10.1 + 3720 N/A N,A

AC Current Function 1 Year Limits (accuracy -

(% of r Number of

counts))

Frequency 300mA Range 3A Range

20Hz 50Hz 1.54 + 163 2.24 + 163

50Hz 1KHz 0.81 + 163 1.5 + 163

1KHz 10KHz 0.72 + 163 1.42 + 163

10KHz 20KHz 0.86 + 163 1.56 + 163

4-4. EQUIPMENT REQUIRED

4-5. All the required test equipment for the Performance
Tests and Calibration Procedures are listed in Table 4-2
(Recommended Test Equipment). The equipment used for
the individual tests is also listed at the beginning of each test
procedure. If any of the recommended equipment is not
available, use substitute equipment. A short description of
the required equipment and the critical specifications
necessary to do the test and calibration procedures is in the
following paragraphs. This information may be helpful in
choosing substitute equipment.

4-6. DC Volts Test and Calibration

4-7. The DC Volts Test and Calibration (DC Volts Function)
requires a very accurate Digital Voltmeter (like the 3456A) as
the Standard. The Digital Voltmeter must be calibrated to its
24 hour dc volts specifications before calibrating and testing
the 3478A (i.e. the 3478A is tested and calibrated within 24
hours after the Digital Voltmeter, used as the standard, has
been calibrated). It is recommended that the Digital Voltmeter
be calibrated in the same temperature environment and leave
it in the environment in which the 3478A is to be calibrated
and tested (e.g. the 3478A’s Reference Temperature, see
Paragraph 4-39). In addition to the Digital Voltmeter, a DC
Volts Standard is required to be used as a very stable voltage
source. The following lists the required equipment and
recommended models.

4-8. Digital Voltmeter. The recommended Digital Voltmeter
is an -hp- Model 3456A. The critical requirements are as
follows:

a. Required voltage range is from 30mV to 300V dc.

b. Accuracy and stability requirements in a 24 hour period

is as follows:

.004% for the 30V and 300V Ranges

±.005% for the 300mV and 3V Ranges
±.025% for the 30mV Range

4-9. DC Volts Standard. The DC Volts Standard chosen is
a Systron Donner Model M107 Precision Voltage Source.
The critical requirements are as follows:

4-1