Keithley 4200-SCS Reference Manual page 259

Model 4200-SCS Reference Manual
Fast, Normal, Quiet, and Custom selections
You can locally select the measurement Speed mode in the ITM Timing window by clicking the
Fast, Normal, Quiet, or Custom radio button. These selections are identical to the selections in
the Speed combo box (refer to
Delay Factor setting
After applying a forced voltage or current, an SMU waits for a delay time before making a
measurement. The delay time allows for source settling. The default delay time is pre-programmed
and range-dependent, to allow for the very long settling times needed at very low current ranges.
The applied delay time is a multiple of the default delay time, and the value in the Delay Factor
edit box specifies this multiple. That is:
Applied delay time = (Default delay time) × (Delay Factor)
For example, if the default delay time is 1ms and the Delay Factor is 0.7, the applied delay time is
0.7ms (1ms × 0.7).
If you select the Custom measurement Speed mode, you can enter a custom Delay Factor of 0
to 100. If you select the Fast, Normal, or Quiet measurement Speed mode, the SMU chooses an
appropriate, fixed Delay Factor.
measurement Speed modes
Table 6-8
Summary of allowed Delay Factor settings
When entering a custom Delay Factor setting, consider the following:
Filter Factor setting
To reduce measurement noise, each 4200-SCS SMU applies filtering, which may include
averaging of multiple readings to make one measurement. The SMU automatically adjusts the
filtering to fit the selected measurement range (this system works particularly well, because
measurements at lower current ranges require much more filtering [and much more time] than at
higher ranges). The value entered in the Filter Factor edit box specifies a multiple of this
preprogrammed filtering.
4200-901-01 Rev. S / May 2017
Speed
Mode
Fast
Normal
Quiet
Custom
• A Delay Factor of 1 allows for a normal amount of settling before the A/D converter is
triggered to make a measurement.
• Each doubling of the Delay Factor doubles the time allowed for settling.
• A delay factor of 0 multiplies the default delay by zero, resulting in no delay.
Return to
Section 6: Keithley Interactive Test Environment (KITE)
Speed combo box later in this
Table 6-8 summarizes allowed Delay Factor settings for various
.
Delay Factor
Settings
0.7
1.0
1.3
0 to 100
Section Topics
section).
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