Racal Instruments 3155, User Manual

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User Manual 3155
Programming Reference 4-13
char last;
}FMPT;
2. Define array FMPT fmWav[<wavelength>]
3. Fill the structure with data array of which each fmWav represents:
pt – S/s value x 14.31655765 (S/s is limited by specified sample clock range)
last – Ored value
0x80 for the last waveform data point
0x01 for marker position
0x00 for all other points
4. Convert pt component of array to long format (Intel binary representation, if neces-
sary)
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
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}
[:STATe] OFF | ON
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.
Command Format
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