Racal Instruments 3162A/B, User Manual

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User Manual 3162A/B
Using The Instrument 3-29
TRACe:DELete: ALL
CAUTION
This command will destroy waveforms that were previously
loaded into memory. After using this command, waveform
segments will line up from address 0 upwards.
Loading Arbitrary
Waveforms
There are three ways to load waveforms into the Model 3162B: by using a
graphical user interface, i.e., WaveCAD, a LabWindows/CVI or LabVIEW driver,
or by low-level programming. When using WaveCAD, disregard most of this
chapter as WaveCAD does the work for you. When writing your own program
or instrument driver, use the following commands to load data into a specific
memory segment.
First, define the work area. Define the segment number, its associated length
and sample clock divider. The segment length must be divisible by eight or an
error will occur. For example, to use segment number 8, give it a length of 1048
points and a sample clock divider of 1, use this command:
TRACe:DEFine 8,1048,1
Next, make segment 8 the active segment. The active segment must be
selected because as waveforms are loaded, the Model 3162B must be notified
as to where to place the data it receives. Select the active segment using the
following command:
TRACe:SELect 8
The next step is to transfer data to the active segment. Data is loaded into the
Model 3162B using high-speed binary transfer. A special command is defined
by IEEE-STD-488.2 for this purpose. High-speed binary transfer allows any 8-
bit bytes (including extended ASCII code) to be transmitted in a message. This
command is particularly useful for sending large quantities of data. The Model
3162B uses this command to receive waveforms from the controller:
TRACe #42096<binary_block>
This command causes the transfer of 2096 bytes of data (1048) points into the
active memory segment. The ASCII "#" ($23) is the start of the binary data
block. "4" designates the number of digits that follow. "2096" is the even
number of bytes to follow. The generator represents binary data as 12-bit
integers, which are sent as two bytes. Therefore, the total number of bytes is
always twice the number of data points in the waveform. For example, 2096
bytes are required to download a waveform with 1048 points. Bytes are sent in