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Front Panel Operation

2-33

2.7.1 Resistance measurements

The Model 6517A can make resistance measurements up to
10

Ω

using the force voltage measure current (FVMI) tech-

nique. From the known sourced voltage and measured cur-
rent, the Model 6517A calculates and displays the resultant
resistance (R = V/I). The V-Source level can be set automat-
ically by the Model 6517A or it can be manually set by the
user.

The following steps summarize the basic steps to measure re-
sistance:

WARNING

Make sure the V-Source is in standby. In
standby, the OPERATE indicator is off.
The OPER key toggles the V-Source be-
tween standby and operate.

NOTE

To ensure proper operation, always enable
zero check ("ZeroCheck" displayed) be-
fore changing functions (V, I, R, or Q).
The Z-CHK key controls zero check.

1. Enable zero check by pressing Z-CHK.
2. Select RESISTANCE from the MEAS-TYPE selection

of the ohms configuration menu. The ohms configura-
tion menu is accessed by pressing CONFIG and the R
(see paragraph 2.7.3 for details).

NOTE

Step 2 can be skipped if the instrument is
already in the resistance measurement
mode.

3. Select the V-Source adjustment mode. With AUTO V-

Source selected, the instrument will automatically select

the optimum V-Source value (40V or 400V) for the mea-
surement range. With MANUAL V-Source selected, you
select the V-Source range and value. The V-Source ad-
justment mode is selected from the VSOURCE item of
the CONFIGURE OHMS menu. See paragraphs 2.7
(Auto V-Source) and 2.7.3 (VSOURCE) for details.

4. Connect the resistance to be measured to the Model

6517A. Figure 2-31 shows typical connections while
Figure 2-32 shows connections using the Model 8002A
High Resistance Test Fixture.

NOTE

The connections in Figure 2-33 assume
that V-Source LO is internally connected
to ammeter LO. This internal connection
is controlled from the METER-CON-
NECT option of the CONFIGURE V-
SOURCE menu (see paragraph 2.9.1).
This LO-to-LO connection can instead be
made by using an external cable to connect
V-Source LO to ammeter LO.

5. Select the ohms function by pressing the R key.
6. If the manual V-Source adjustment mode is selected, use

the

, and the VOLTAGE SOURCE

▲

and

▼

keys to set the voltage level. The V-Source range can be
changed from the RANGE item of the CONFIGURE V-
SOURCE menu. See paragraph 2.9.2 for details on set-
ting range and level for the V-Source. Note that you will
not be able to adjust the V-Source if AUTO V-Source is
selected.

WARNING

To avoid a possible shock hazard, do not
use a voltage level that exceeds the max-
imum input voltage rating of the test fix-
ture. For example, the maximum input
voltage to the Model 8002A High Resis-
tance Test Fixture must not exceed
200V peak.

7. Use the

▲

and

▼

RANGE keys to select the resistance

measurement range, or select AUTO range. Note that
with AUTO range selected, the instrument will not go to
the 2T

Ω

, 20T

Ω

and 200T

Ω

ranges.

NOTE

For optimum accuracy, leakage currents in
the test fixture can be cancelled by per-
forming REL on the current component of
the measurement. To cancel leakage cur-
rent, perform “Cancelling Test Fixture
Leakage Current” which follows Step 9 of
this procedure.

Table 2-11

Ohms reading ranges and AUTO V-Source

Reading range

AUTO V-Source

Test

voltage

Amps

range

200k

Ω

– 2M

Ω