R&S®SML / R&S®SMV03 Structure and Syntax of Device Messages
1090.3123.12 E-6 5.9
Structure of Command Lines
A command line may contain one or several commands. It is terminated by <New Line>, <New Line>
with EOI or EOI together with the last data byte. QuickBASIC automatically produces EOI together with
the last data byte.
Several commands in a command line are separated by a semicolon ";". If the next command belongs
to a different command system, the semicolon is followed by a colon.
Example:
CALL IBWRT(generator%, "SOURce:POWer:CENTer MINimum;:OUTPut:ATTenuation 10")
This command line contains two commands. The first command belongs to the SOURce
system and defines the center frequency of the output signal. The second command
belongs to the OUTPut system and sets the attenuation of the output signal.
If successive commands belong to the same system and thus have one or several levels in common,
the command line can be abbreviated. To this end, the second command (after the semicolon) is
started with the level that lies below the common levels (see also Fig. 5-1). The colon following the
semicolon must be omitted in this case.
Example:
CALL IBWRT(generator%, "SOURce:FM:MODE LOCKed;:SOURce:FM:INTernal:FREQuency 1kHz")
This command line is represented in its full length and contains two commands separated
from each other by the semicolon. The two commands belong to the SOURce command
system, subsystem FM, ie they have two common levels.
To abbreviate the command line, the second command is started with the level below
SOURce:FM. The colon after the semicolon is omitted.
The abbreviated form of the command line reads as follows:
CALL IBWRT(generator%, "SOURce:FM
:MODE LOCKed;INTernal:FREQuency 1kHz")
However, a new command line always has to be started with the complete path.
Example: CALL IBWRT(generator%, "SOURce:FM:MODE LOCKed")
CALL IBWRT(generator%, "SOURce:FM:INTernal:FREQuency 1kHz")
Responses to Queries
For each setting command, a query is defined unless explicitly specified otherwise. The query is formed
by adding a question mark to the setting command in question. Responses to queries to the SCPI
standard are partly subject to stricter rules than responses to the IEEE 488.2 standard.
1. The requested parameter is transmitted without header.
Example: SOURce:EXTernal:COUPling? Response: AC
2. Maximum values, minimum values and all further quantities requested via a special text parameter
are returned as numerical values.
Example: FREQuency? MAX Response: 10E3
3. Numerical values are output without a unit. Physical quantities are referred to the basic units or to
the units set with the Unit command.
Example: FREQuency? Response: 1E6 for 1 MHz
4. Truth values (Boolean parameters) are returned as 0 (for Off) and 1 (for On).
Example: OUTPut:STATe? Response: 1
5. Text (character data) is returned in a short form.
Example: SOURce:FM:SOURce? Response: INT
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