Keithley 6221 User Manual

5-56 Delta, Pulse Delta, and Differential Conductance Model 6220/6221 Reference Manual
Return to Section 5 topics
formed at each stepped delta level. Delta is a magnitude and is therefore always
set as a positive value. Delta can be set from 0 to 105mA. The default Delta set-
ting is 1µA.
Delay – The delay for Differential Conductance is used to allow the current source
to settle when the output changes to the next stepped delta level. This delay
occurs after a trigger from the Model 2182/2182A is received. This delay is shown
in Figure 5-15. Delay can be set from 1ms to 9999.999s. The default delay setting
is 2ms.
Compliance Abort – By enabling (YES) Compliance Abort, Differential Conduc-
tance operation will abort if the current source goes into compliance. By default,
Compliance Abort is disabled (NO).
Details on setting the sweep parameters are explained in “Operation,” on
page 5-59.
Arming process
After Differential Conductance is configured, the test is armed by pressing the
COND key or sending SOUR:DCON:ARM. During the arming process, the Model
622x establishes communications with the Model 2182/2182A and performs a
series of operations.
Communications, setup commands, sweep table, and repeating filter
The Model 622x performs a communications test and sends setup commands to
the Model 2182/2182A. These operations are explained in “Communications test
and setup commands,” on page 5-12.
The Model 622x builds a sweep table of source values to be used for the Differen-
tial Conductance test. For details, see “Internal sweep table,” on page 5-12.
For Differential Conductance, only the repeating average filter can be used (if
enabled). If the moving average filter is enabled, the filter type will change to
repeating when Differential Conductance is armed. See Section 6 for details, refer
to the repeating average filter.
NOTE The source range for the Model 622x is automatically set to
the best fixed range when Differential Conductance is
armed.
NOTE Jitter – For Differential Conductance, step-to-step timing
may jitter as much as 1ms. This jitter can be eliminated by
disabling the front panel. For details, see “Step-to-step
timing jitter,” on page 1-18.
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Keithley 6221 Specifications

General

Interface	GPIB, RS-232
Communication Interface	GPIB, RS-232
Current Sourcing Accuracy	±(0.03% of output + 20 pA)
Current Sinking Accuracy	±(0.03% of output + 20 pA)
Output Resolution	100 fA
Output Accuracy	±(0.03% of output + 20 pA)
Power Requirements	100 V to 240 V AC, 50/60 Hz