Trace Subsystem - Keithley 2520 User Manual

14-56 SCPI Command Reference

TRACe subsystem

The TRACe subsystem is mostly a diagnostic tool for debugging connections and setup. In
normal operation, a 14-bit A/D converter in the Model 2520 samples at 10MHz rate, and
then, an internal Digital Signal Processor (DSP) interprets the A/D samples over the pulse
width in order to determine the pulse level value, or a DC average, which are then sent
back to the user. Using the TRACe subsystem, it is possible to effectively bypass the DSP
calculations and directly query single calibrated samples. This feature provides basic 14-
bit 10MHz digital storage oscilloscope capabilities. You can reconstruct a pulse to deter-
mine pulse parameters such as settling times, overshoot, and undershoot.
NOTE
Read sample buffer
DATA?
:TRACe:DATA?
Description
VALue? [<NRf>]
:TRACe:DATA:VALue? [<NRf>]
Description
None of the TRACe features are available over front panel. TRAC:DATA? And
TRAC:DATA:VAL? will return errors unless SOUR1:MODE is FIXed, TRIG-
ger:COUNT is 1, and a reading has been triggered.
This command returns the raw sample data taken during the latest trig-
gered reading. The number of samples is specified by
TRAC:DATA:POINts. The sample elements returned are specified by
FORM:ELEM:TRAC (see
This command returns the specified sample after the start of the source
current pulse. If no parameter is specified, it returns the sample that
immediately followed the one returned for the previous
TRAC:DATA:VAL? query. If no TRAC:DATA:VAL? query was sent
after the last INIT command, it returns the first sample after start of
pulse. The sample elements returned are specified by
FORM:ELEM:TRAC (see
Model 2520 User's Manual
Read raw samples from buffer
"FORMat subsystem," page
Return specific sample
"FORMat subsystem," page
14-19).
14-19).