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User Manual 3155
2. Define array FMPT fmWav[<wavelength>]
3. Fill the structure with data array of which each fmWav represents:
4. Convert pt component of array to long format (Intel binary representation, if neces-
5. Call DLL function SendBlock(hInstr, 2, "", (void*)fmWav, <wavelength>*5)
Note that the arbitrary FM waveform data array is comprised of 5 bytes. The most significant
4 bytes contain waveform data. The lease significant byte ("last") flags marker position and
end of data file. Therefore, each arbitrary FM waveform data point is represented by 5 bytes.
Introduction To
SCPI
Command Format
char last;
}FMPT;
pt – S/s value x 14.31655765 (S/s is limited by specified sample clock range)
last – Ored value
sary)
Commands to program the instrument over the GPIB are defined by
the SCPI 1993.0 standard. The SCPI standard defines a common
language protocol. It goes one step further than IEEE-STD-488.2 and
defines a standard set of commands to control every programmable
aspect of the instrument. It also defines the format of command pa-
rameters and the format of values returned by the instrument.
SCPI is an ASCII-based instrument command language designed for
test and measurement instruments. SCPI commands are based on a
hierarchical structure known as a tree system. In this system, associ-
ated commands are grouped together under a common node or root,
thus forming subsystems.
Part of the OUTPut subsystem is shown below to illustrate the tree
system:
:OUTPut
:FILTer
[:LPASs] {NONE|25M|50M|ALL}
OUTPut is the root keyword of the command; FILTer and STATe are
second level keywords. LPASs is third level keyword. A colon ( : )
separates a command keyword from a lower level keyword.
The format used to show commands in this manual is shown below:
FREQuency {<frequency>|MINimum|MAXimum}
The command syntax shows most commands (and some parame-
ters) as a mixture of upper and lowercase letters. The uppercase
letters indicate the abbreviated spelling for the command. For shorter
program lines, send the abbreviated form. For better program read-
ability, use the long form.
For example, in the above syntax statement, FREQ and
0x80 for the last waveform data point
0x01 for marker position
0x00 for all other points
[:STATe] OFF | ON
Programming Reference 4-13
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