Keysight N6705 Service Manual page 11

Performance Verification 2
Measurement Techniques
Voltmeter
To ensure that the values read by the voltmeter during both the verification
procedure and the calibration procedure are not affected by the
instantaneous measurement of the AC peaks of the output current ripple,
make several DC measurements and average them.
If you are using a Keysight 3458A DMM, you can set up the voltmeter to
do this automatically. From the instrument's front panel, program 100
power line cycles per measurement. Press NPLC 100 ENTER.
If you are using a Keysight 3458A DMM, turn on auto-calibration (ACAL)
and the autorange function (ARANGE). For best results, auto-calibration
should be performed every 24 hours when verifying or calibrating models
N678xA SMU.
Current-Monitoring Resistor
The 4-terminal current shunt is used to eliminate output current
measurement error caused by voltage drops in the load leads and
connections. It has special current-monitoring terminals inside the load
connection terminals. Connect the voltmeter directly to these current-
monitoring terminals.
Electronic Load
Many of the test procedures require the use of a variable load capable of
dissipating the required power. If a variable resistor is used, switches
should be used to connect, disconnect, or short the load resistor. For
most tests, an electronic load can be used. The electronic load is
considerably easier to use than load resistors, but it may not be fast
enough to test transient recovery time and may be too noisy for the noise
(PARD) tests.
Fixed load resistors may be used in place of a variable load, with minor
changes to the test procedures. Also, if computer controlled test setups are
used, the relatively slow (compared to computers and system voltmeters)
settling times and slew rates of the DC Power Analyzer may have to be taken
into account. Use "Wait" statements in your program if the test system is
faster than the DC Power Analyzer.
Note that an N6784A SMU power module should be used as the load
when testing transient response on models N678xA SMU and N6783A.
Front Panel Connections
Except for Test Setup A, do not connect anything to the Sense
terminals. Check the front panel 4 wire LED to see whether 4 wire
sensing is enabled (LED is lit) or disabled (LED not lit). To change the 4
wire sense settings, press [Settings], then navigate to and select
Advanced. Under Sense, select Local or 4 Wire sensing.
Connect all leads to the output terminals as shown in the figure to the
left.
Model N6705 Service Guide 11