User manual

A-2 Return to Section Topics 3390-900-01 Rev. C / January 2009
Appendix A: SCPI Command Reference Model 3390 Arbitrary Waveform Generator User’s Manual
SCPI commands
Standard commands for programmable instruments (SCPI) is an ASCII-based command language
designed for testing and measurement instruments. SCPI is based on a hierarchical structure, also
known as a tree system. In this system, associated commands are grouped together under a
common root, and form subsystems. A portion of the system-related commands is shown as an
example:
SYSTem:
ERRor?
BEEPer
BEEPer:
STATe
SYSTem is the root keyword of the command; ERRor and BEEPer are second-level keywords; and
STATe is a third-level keyword. A colon (:) separates the keyword levels.
Command format
Most commands (and some parameters) are expressed as a combination of upper- and lower-
case letters. The upper-case letters indicate the letters that must be specified for the command.
For shorter program lines, send the abbreviated form. For better program readability, use the long
form. For example, STAR and START are both acceptable forms of the same command. You may
also mix upper- or lower-case letters in a command. For example, START, star, and Star are
all acceptable forms of the same command. Other forms, such as STA will generate an error.
• Braces ( { } ) enclose parameter choices for a command string. The braces are not sent with
the command.
• Vertical bars ( | ) separate multiple parameter choices for a command string.
• Triangle brackets ( < > ) indicate that you must specify a value for the enclosed parameter.
The brackets are not sent with the command string. You must specify a value for the
parameter such as STAR 6000.
• Some parameters are enclosed in square brackets ( [ ] ). The brackets indicate that the
parameter is optional and can be omitted. The brackets are not sent with the command
string. If you do not specify a value for an optional parameter, the waveform generator uses
the default value.
Command separators
A colon ( : ) is used to separate a command keyword from a lower-level keyword. You must insert
a blank space to separate a parameter from a command keyword. If a command requires more
than one parameter, you must use a comma between two parameters:
APPL:SIN 5 KHZ, 3.0 VPP, -2.5 V
A semicolon ( ; ) is used to separate commands within the same subsystem, and can reduce
typing efforts. For example, sending the following command string:
BURSt:MODE TRIG; NCYCles 10
is the same as sending the following two commands:
BURSt:MODE TRIG
BURSt:NCYCles 10
Use a colon and a semicolon to link commands from different subsystems. For example, in the
following command string, an error is generated if you do not use both the colon and semicolon:
BURSt:STATe ON;:TRIG:SOUR EXT