Keithley 2520, User Manual, Page: 99 / 329

6-4 Range, Filter, and Math Model 2520 User’s Manual
Range programming example
Table 6-5 shows a programming example for controlling range. The Model 2520 is set up
as follows:
• Laser diode voltage measure range: 5V.
• Laser diode current source range: 500mA.
• Detector 1 current range: 10mA.
• Detector 2 current range: 100mA.
Filter
Filtering stabilizes noisy measurements caused by noisy input signals. The Model 2520
uses an averaging type filter for all three measurements. The number of readings averaged
can be set between 1 and 100. However, the more filtering that is used (higher number of
readings averaged), the slower the measurement process becomes.
Averaging filter overview
When the averaging filter is enabled, the unit cycles through the complete delay-pulse
cycle for each filter sample measurement. (See
Section 5 for delay-pulse details.) The
measurement results for all delay-pulse cycles are then averaged to give one “filtered”
reading.
If the filter is enabled in sweep mode (See Section 7 ), each step of the sweep will effec-
tively be repeated for the filter count number of times. Figure 6-1 shows an example of a
sweep from 10mA to 30mA with a filter count of 3. Note that three delay-pulse cycles are
performed at each step. In this example, three readings per measurement channel will be
returned by a READ? query.
Table 6-5
Range programming example
Command Description
*RST
:SENS1:VOLT:RANG 5
:SOUR1:CURR:RANG 0.5
:SENS2:CURR:RANG 10e-3
:SENS3:CURR:RANG 100e-3
:OUTP1 ON
:READ?
:OUTP1 OFF Restore GPIB defaults.
5V laser diode measure range.
500mA laser diode source range.
10mA detector 1 current range.
100mA detector 2 current range.
Turn on outputs.
Trigger and acquire readings.
Turn off outputs.