Keithley 2750, Руководство пользователя

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Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-17
Connections
NOTE When using the front panel inputs, the INPUTS switch must be in the “F” (out)
position. For switching modules, it must be in the “R” (in) position.
Front panel inputs
Connections for resistance measurements are shown in Figure 3-6 . For 2-wire resistance
measurements (
Ω
2), connect the test leads to INPUT HI and LO as shown in Figure 3-6 A.
For 4-wire resistance (
Ω
4), connect the test leads to INPUT HI and LO, and SENSE
Ω
4 HI
and LO as shown in Figure 3-6 B.
Model 7700 switching module
Connections for the switching module are shown in Figure 3-7 . As shown in Figure 3-7 A,
each of the 20 channels can be used to perform
Ω
2 measurements. For
Ω
4 measurements, a
channel pair is used for each 4-wire measurement as shown in Figure 3-7 B.
For
Ω
4 connections, channels 1 through 10 (which are used as the INPUT terminals) are
paired to channels 11 through 20 (which are used as the SENSE terminals). Channel 1 is
paired to channel 11, channel 2 is paired to channel 12, and so on.
Shielding
To achieve a stable reading, it helps to shield resistances greater than 100k
Ω
. As shown in
Figure 3-6 and Figure 3-7 , place the resistance in a shielded enclosure and connect the
shield to the input low terminal of the instrument electrically.
Cable leakage
For high resistance measurements in a high humidity environment, use Teflon™ insulated
cables to minimize errors due to cable leakage.
2750-900-01.book Page 17 Wednesday, August 3, 2011 7:56 AM