Loading Arbitrary Waveforms - Racal Instruments 3151 User Manual

Loading Arbitrary
Waveforms
Using The Instrument 3-26
This command will destroy waveforms that were
previously loaded into memory. After using this
command, waveform segments will line-up from address
0 upwards.
There are two ways to load waveforms into the Model 3151/3151A;
using a graphical user interface, i.e., WaveCAD, or low-level
programming. When using WaveCAD, disregard most of this chapter
as WaveCAD does the work for you. When writing your own code,
use the following commands to load data into a specific memory
segment.
First, define the work area. Define the segment number and its
associated length. Segment length must be an even number. For
example, to use segment number 8 and give it a length of 1000
points, use this command:
TRACe:DEFine 8,1000
Next, make segment 8 the active segment. The active segment must
be selected because as waveforms are loaded, the Model
3151/3151A 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 3151/3151A 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
3151/3151A uses this command to receive waveforms from the
controller:
TRACe #42000<binary_block>
This command causes the transfer of 2000 bytes of data (1000)
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. "2000" 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, 2000 bytes are required to
download a waveform with 1000 points. Bytes are sent in byte-high,
byte-low order. The FORM:SWAP command can be used to reverse
3151 And 3151A User Manual
CAUTION