Operating Manual R&S SMIQ - Volume 1 - Rohde & Schwarz

Structure and Syntax of the Device MessagesSMIQ3.4.3 Structure of a Command LineA command line may consist of one or several commands. It is terminated by a , a with EOI or an EOI together with the last data byte. Quick BASIC automatically produces an EOItogether with the last data byte.Several commands in a command line are separated by a semicolon ";". If the next command belongsto 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 is part of the SOURcesystem and is used to specify the center frequency of the output signal. The secondcommand is part of the OUTPut system and sets the attenuation of the output signal.If the successive commands belong to the same system, having one or several levels in common, thecommand line can be abbreviated. To this end, the second command after the semicolon starts with thelevel that lies below the common levels (see also Fig. 3-1). The colon following the semicolon must beomitted 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 separatedfrom each other by the semicolon. Both commands are part of the SOURce commandsystem, subsystem FM, i.e. they have two common levels.When abbreviating the command line, the second command begins with the level belowSOURce: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 begins with the complete path.Example: CALL IBWRT(generator%, "SOURce:FM:MODE LOCKed")CALL IBWRT(generator%, "SOURce:FM:INTernal:FREQuency 1kHz")3.4.4 Responses to QueriesA query is defined for each setting command unless explicitly specified otherwise. It is formed by addinga question mark to the associated setting command. According to SCPI, the responses to queries arepartly subject to stricter rules than in standard IEEE 488.2.1. The requested parameter is transmitted without header.Example: SOURce:EXTernal:COUPling? Response: AC2. Maximum values, minimum values and all further quantities, which are requested via a special textparameter are returned as numerical values.Example: FREQuency? MAX Response: 10E33. Numerical values are output without a unit. Physical quantities are referred to the basic units or to theunits set using the Unit command.Example: FREQuency? Response: 1E6 for 1 MHz4. Truth values are returned as 0 (for OFF) and 1 (for ON).Example: OUTPut:STATe? Response: 15. Text (character data) is returned in a short form (see also Section 3.4.5).Example: SOURce:FM:SOURce? Response: INT1125.5555.03 3.8E-7