User`s guide

6 Advanced Source and Measurement Functions
168 Model N6705 User’s Guide
External Data Logging
NOTE
The external Data Logger function is not available if Option 055 has been
ordered.
In addition to the built-in data logger, the DC Power Analyzer has an
external data logger (Elog) function that lets you log voltage and
current measurements from all four outputs directly to an internal
FIFO (first-in, first-out) buffer. Note that this buffer is only large
enough to hold about 20 seconds of accumulated measurements. The
following table lists the major differences between the built-in and
external data loggers.
Function Built-in Data Logger External Data Logger
Data viewing Optimized for viewing the
measurements on the DC Power
Analyzer’s display.
No front panel view or front panel
control.
Data storage Stores the measurements to an
internal file. Can be left unattended
for an extended time and results
can be viewed afterward.
Buffers measurements for about 20
seconds and requires that the
computer periodically reads
measurements to prevent the DC
Power Analyzer’s buffer from
overflowing. The computer needs to
provide the data storage function.
Measurement
resources
Allocates all the measurement
resources of ALL outputs, even if
data logging is only enabled on
some of the outputs.
Runs independently on each output.
Some outputs can be running an
external data log, while the remaining
outputs can be used in front panel
control or used for other SCPI
functions.
Interleaved mode Interleaved mode allows the data
logger to log both voltage and
current on power modules that
have only one measurement
converter.
Interleaved mode is not available. If a
power module has only one
measurement converter, then either
voltage or current can be logged, but
not both.
Logging rate Can log data at up to 20.48
microseconds for one parameter.
Can log data at up to 102.4
microseconds for one parameter with
data format = real.
Programming the external data logger consists of:
 Selecting the measurement functions and ranges.
 Specifying the measurement integration period.
 Selecting the trigger source.
 Triggering the data logger.
 Retrieving the data log measurement.