3-64 BOP HIPWR 111315Each time the parser encounters a keyword separator, the parser moves to the next indentedlevel of the tree diagram. As an example, the STATus branch is a root level branch that hasthree sub-branches: OPERation, PRESet, and QUEStionable. The following illustrates howSCPI code is interpreted by the parser:STAT:PRESThe parser returns to the root due to the message terminator.STAT:OPER?;PRESThe parser moves one level in from STAT. The next command is expected at the level definedby the colon in front of OPER?. Thus you can combine the following message unitsSTAT:OPER? and STAT:PRES;STAT:OPER:COND?;ENAB 16After the OPER:COND? message unit, the parser moves in one level from OPER, allowing theabbreviated notation for STAT:OPER:ENAB.3.6.6 PROGRAM MESSAGE SYNTAX SUMMARY• Common commands begin with an asterisk (*).• Queries end with a question mark (?).• Program messages consist of a root keyword and, in some cases, one or more messageunits separated by a colon (:) followed by a message terminator. Several message unitsof a program message may be separated by a semicolon (;) without repeating the rootkeyword.• If a program message has more than one message unit, then a colon (:) must precedethe next keyword in order to set the parser back to the root (otherwise the next keywordwill be taken as a subunit of the previous message unit).e.g., the command meas:volt?;curr? will read output voltage and output current sinceboth volt? and curr? are interpreted as subunits of the meas command.• Several commands may be sent as one message; a line feed terminates the message.Commands sent together are separated by a semicolon (;). The first command in a mes-sage starts at the root, therefor a colon (:) at the beginning is not mandatory. E.g., thecommand meas:volt?;:curr? will read output voltage and programmed current since thecolon preceding curr? indicates that curr? is not part of the meas command and starts atthe root.• UPPER case letters in mnemonics are mandatory (short form). Lower case letters mayeither be omitted, or must be specified completely (long form)e.g., INSTrument (long form) has the same effect as INST (short form).• Commands/queries may be given in upper/lower case (long form)e.g., SoUrCe is allowed.• Text shown between brackets [ ] is optional.e.g., :[SOUR]VOLT:[LEV] TRIG has the same effect as :VOLT TRIG
