Introduction
The commands of the Waveform subsystem are used to transfer
waveform data from the oscilloscope to a controller. The waveform
record is actually contained in two portions; the waveform data and
preamble. The waveform data is the actual data acquired for each
point when a DIGitize command is executed. The preamble contains
the information for interpreting waveform data. Data in the preamble
includes number of points acquired, format of acquired data, average
count and the type of acquired data. The preamble also contains the
X and Y increments, origins, and references for the acquired data for
translation to time and voltage values.
The values set in the preamble are based on the settings of the
variables in the Acquire, Waveform, Channel, and Timebase
subsystems. The Acquire subsystem determines the acquisition type
and the average count, the Waveform subsystem sets the number of
points and format mode for sending waveform data over the remote
interface and the Channel and Timebase subsystems set all the X - Y
parameters.
Refer to Figure 35-3 for the Waveform Subsystem Syntax Diagram.
Data Acquisition Types
The two acquisition types that may be chosen are Normal or Average.
Normal Mode
In the Normal mode, with ACCumulate command OFF, the oscilloscope
acquires waveform data and then displays the waveform. When the
oscilloscope takes a new acquisition, the previously acquired waveform is
erased from the display and replaced by the newly acquired waveform.
When the ACCumulate is set ON, the oscilloscope displays all the waveform
acquisitions without erasing the previously acquired waveform.
35-2