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2600AS-901-01 Rev. B / September 2008
Section 3: Basic Operation
Series 2600A System SourceMeter® Instruments Reference Manual
WARNING
Hazardous voltages may be present on the output and guard
terminals. To prevent electrical shock that could cause injury or
death, NEVER make or break connections to the Series 2600A
while the output is on. Power off the equipment from the front
panel or disconnect the main power cord from the rear of the
SourceMeter instrument before handling cables connected to the
outputs. Putting the equipment into standby does not guarantee
the outputs are not powered if a hardware or software fault occurs.
To take an ohms measurement:
1.
For the Model 2602A/2612A/2636A, press the
DISPLAY
key to select the single-channel
display mode.
2.
Press
SRC
to select the current source function, then set the output current to the desired
value based on the expected resistance. See Step 1 of
earlier in this section.
3.
Press the
LIMIT
key. Set the voltage limit high enough for the expected voltage across the
resistance to be measured based on both the resistance value and programmed source
current. See Step 2 of
Front panel source-measure procedure
earlier in this section.
4.
Press the
MEAS
or
MODE
key to display voltage, then make sure that AUTO measurement
range is on.
5.
Press the
MEAS
or
MODE
key to display ohms.
6.
Turn on the output, then note the reading on the display. If necessary, press the
TRIG
key to
display continuous readings. Turn off the output when finished.
Ohms sensing
Ohms measurements can be made using either 2-wire or 4-wire sensing (see
for
information on connections and sensing methods).
The 2-wire sensing method has the advantage of requiring only two test leads. However, as shown
in
, test lead resistance can seriously affect the accuracy of 2-wire resistance
measurements, particularly with lower resistance values. The 4-wire sensing method shown in
minimizes or eliminates the effects of lead resistance by measuring the voltage across
the resistor under test with a second set of test leads. Because of the high input impedance of the
voltmeter, the current through the sense leads is negligible, and the measured voltage is
essentially the same as the voltage across the resistor under test.
