Dc Voltmeter Input Resistance Test; Performance Test; Dc Voltmeter Accuracy Test - HP 3455A Operating And Service Manual

Mudel 3455A
Section IV
Table 4-8. Four-Wire Ohms Accuracy Test.
{A}
Test Limits
(High Res. Off)
(B)
Test Limits
(High Res. On)
Oecade
Resistor 24 Hour*
90 Day*
24 Hour*
90 Day*
100 2 0.099993 to 0.100007
0.099990 to 0.100010
0.999971 to 1.000029 0.999960 to 1.000040
tkQ
9.99935 to 10.00065
10 kQ
100 kQ
MQ
10 MQ
9.99951 to 10.00049
99.9975 to 100.0025
999.876 to 1000.124
9989.96 to 10010.04
99.9959 to 100.0041
999.860 to 1000.140
9989.95 to 10010.05
*These test limits do not include the temperature coefficients that must be added if the instrument is operated outside of
the temperature range over which the 24-hour or 90-day specifications apply (see Table 1-1). Derive 6& month test limits
fromOhms Accuracy specifications listed in Table 1-1.
b. Using a shielded cable equipped with banana-plug
connectors, connect the Decade Resistor to the INPUT
of the 3455A. Set the Decade Resistor to 100 K ohms.
c. Algebraically add the Decade Resistor's correction
factor to the 3455A reading. The algebraic sum should
be within the test Limits given in Table 4-7, verifying the
3455A 2-wire ohms accuracy.
d. Set the 3455A controls as follows:
FUNCTION ........... 4 WIRE K OHM
RANGE ® 28.5 sisi 3.4 os, arse beta hioe hee 0.1
HIGH RESOLUTION ............. OFF
e. Set the Decade. Resistor to 100 ohms. Connect a
shielded cable, equipped with banana-plug connectors,
between the 3455A OHM SIGNAL output and the input
of the Decade Resistor. (Leave the other cable con-
nected between the 3455A INPUT and the input of the
Decade Resistor).
f. Algebraically add the Decade Resistor's correction
factor to the 3455A reading. The algebraic sum should
be within the Test Limits given in Table 4-8 (A), verify-
ing the 3455A 4-wire ohms accuracy with High Resolu-
tion off.
g. Set the 3455A RANGE to | and HIGH RESOLU-
TION to ON. Set the Decade Resistor to 1,000 ohms.
h. Algebraically add the Decade Resistor's correction
factor to the 3455A reading. The algebraic sum should
be within the Test Limits given in Table 4-8(B), verify-
ing the 3455A 4-wire ohms accuracy with High Resolu-
tion on.
i. Repeat Step h for each additional Decade Resistor
setting and 3455A Range listed in Table 4-8 (B).
oe" DC VOLTMETER INPUT RESISTANCE TEST.
is
Equipment Required:
DC Standard Systron Donner Model M106A
Resistor (1 MQ + 0.01% 1/4 W -hp- part
number 0811-0202)
a. Connect the low output of the DC Standard to the
Low Input terminal of the 3455A. Using short clip leads
insert the 1 megohm resistor in series between the DC
Standard's high output and the High INPUT terminal
of the 3455A. Connect a clip lead across the resistor.
b. Set the 3455A controls as follows:
FUNCTION
RANGE 3 iincedah cade dined eee
HIGH RESOLUTION ............-- ON
GUARD ...... eee ec eee e nee ON
c. Adjust the DC Standard for a 3455A reading of
+ 10.00000 V.
d. Remove the clip lead from across the 1 megohm
Tesistor.
e. The 3455A reading should be between 9.99900 V
and 10.00000 V, verifying that the input resistance is
greater than 10!° ohms.
f. Set the 3455A RANGE to 100 V; AUTO-CAL off.
Reconnect the clip lead across the 1 megohm resistor.
g. Adjust the DC Standard for a 3455A reading of
+ 10.00000 V.
h. Remove the clip lead from across the 1 megohm
resistor.
i. The 3455A reading should be between + 9.0900 V
and + 9.0917 V, verifying that the input resistance is 10
megohms + 0.1%.
4-39 PERFORMANCE TEST.
440. DC VOLTMETER ACCURACY TEST.