Test Procedure - HP 3455A Operating And Service Manual

Scetion 1V
4-41. The DC Transfer Standard required for the
following test must be calibrated to a 1.017 V to 1.019 V
standard cell that has been calibrated by the National
Bureau of Standards (NBS). If the 3455A is to be tested
for its 24-hour accuracy specifications, the Transfer
Standard must be adjusted for optimum 1-volt and
10-volt output accuracy using NBS-calibrated stan-
dards. It is recommended that the Transfer Standard be
calibrated and adjusted just prior to use. After calibra-
tion, it should be left on and, if possible, kept in a con-
trolled environment where the ambient temperature is
within one or two degrees of the temperature in which it
was calibrated. The following procedure should be per-
formed in that same environment.
4-42. If the recommended DC Transfer Standard or its
equivalent is not available, an NBS-calibrated standard
cell (1.017 V to 1.019 V) can be substituted. If this is
done, check the full-scale accuracy of the 3455A 1 Vand
10 V ranges using the Reference Divider recommended
in the procedue.
4.43, Test Procedure.
Equipment Required:
Reference Divider (Fluke Model 750A)
DC Transfer Standard (Fluke Model 731A)
DC Standard (Systron Donner Model M106A)
DC Null Voltmeter (-hp- Model 419A)
a. Set the 3455A controls as follows:
FUNCTION 22... .. cece eee eens
RANGE. oiicicetisCsaSiis sha kiob vows s
HIGH RESOLUTION ..
AUTO CAL ...........
GUARD iis os sh etioe eran ese wnaee tes
TRIGGER ............0005
b. Set the DC Transfer Standard for an output of 1
V. Connect the output of the transfer standard to the
3455A INPUT.
c. The 3455A reading should be within the test limits
listed in Table 4-9, verifying its 1-volt full-scale accuracy
with High Resolution off.
Tabla 4-9. OC Accuracy Test (t V, 10 ¥ Full-Scale; High
Resolution Off).
Input 3455A 24 Hour 90 Day
Level Hange Test Limits Limits
lv 1 V J0.99996 to 1.00004 |0.99993 to 1.00007
10V 10 V'} 9.9997 to 10.0003 | 9.9994 to 10.0006
d. Set the 3455A HIGH RESOLUTION to ON. The
3455A reading should be within the test limits listed in
Table 4-10, verifying its 1-volt full scale accuracy with
High Resolution on.
4-10
Model 3455A
e. Set the 3455A RANGE to 10 V. Set the Transfer
Standard for an output of 10 V. The 3455A reading
should be within the test limits listed in Table 4-10, veri-
fying its 10-volt full scale accuracy with High Resolu-
tion on.
Table 4-10. DC Acuracy Test (1 ¥, 10 ¥ Full Scale; High
Resolution On).
24 Hour 90 Day
1V_ 1 -V10.999966 to 1.000034/0.999936 to 1.000064
10V 10 V] 9.99977 to 10.00023] 9.99947 to 10.00053
f. Set the 3455A HIGH RESOLUTION to OFF. The
3455A reading should be within test limits listed in
Table 4-9, verifying its 10-volt full scale accuracy with
High Resolution off.
g. Set the Transfer Standard for an output of 1 V and
set the 3455A RANGE to | V. Set the 34554 GUARD
to OFF; connect the 3455A GUARD terminal to the
High INPUT terminal.
h. Reverse the 3455A INPUT connection to obtain a
negative 1 V reading. Repeat Steps c through f to verify
the 1 V and 10 V full-scale accuracy for negative
readings.
i. Disconnect the Transfer Standard from the 3455A
INPUT. Disconnect the GUARD terminal from the
High INPUT terminal and set the GUARD to ON.
j. Using short pieces of number 20 AWG (or thinner)
insulated solid copper wire, connect the Transfer Stan-
dard and DC Null Voltmeter to the Reference Divider as
shown in Figure 4-4.
k. Turn off the DC Standard's output. Using 24"' (or
shorter) shielded cables equipped with banana-plug con-
nectors, connect the DC Standard and the 3455A to the
Reference Divider as shown in Figure 4-4.
1. Set the Standard Cell Voltage controls on the
Reference Divider to correspond to the calibrated
standard-cell setting on the Transfer Standard. Set the
Transfer Standard to output the calibrated standard-cell
voltage.
m. Zero the DC Null Voltmeter on its 3 microvolt
range and then set it to the 300 microvolt range.
n. Set the Reference Divider's Input Voltage switch
to 1000 V and center its course and fine adjustment con-
trols. Set the Reference Divider's Output Voltage switch
to 1000 V.
o. Set the 3455A controls as follows: