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7. SCPI COMMAND REFERENCE
7.1. COMMAND SYNTAX
7.1.1. General SCPI Rules
Terminator: no terminator is required, but carriage-returns or line feeds at the end of the
SCPI message is allowed
Characters: commands are made of printable letters, numbers, spaces and some
punctuations. Letters may be capital or small; commands are not case-sensitive
Spaces: there must be no spaces within the command. There must be a space between a
command and it’s parameter (or setting). For queries, there cannot be a space before the
question mark
Abbreviations: most SCPI words have an abbreviated form. The full word or the full
abbreviation must be used, no partial abbreviations are allowed
Numbers: numbers may have leading and trailing decimal zeroes, up to 12 characters total.
The “+” is optional for positive values. The decimal point is optional for whole numbers.
Commas for European style decimals are not allowed. Exponential numbers (example:
“1.35E+2”) are not allowed
Errors: If a command syntax is not correct, or if a setting is not acceptable, then the
command is ignored. To check if the command is accepted, it is necessary to read from the
SYSTEM:ERROR queue (see section 7.8.1). The Standard Event Status Register also has a
bit to indicate command errors (*ESR, see section 7.8.7)
Command Queries: almost every command has a query form to read back the command’s
last setting. The query form replaces the command’s parameter with a question mark.
No space is allowed between the command and the “?”. For example, if the command
“:VOLT 23” is sent, the query form “:VOLT?” will respond with “23”
Multiple Commands in One Line: Several commands may be sent as one line if they are
separated by a semi-colon. These are also called concatenated commands. If one of the
commands returns an error, the subsequent commands are skipped. Do not put two queries
in one concatenated command because the response from first query cannot be read back
7.1.2. Document Syntax
Courier Font Represent SCPI commands or responses
ABBReviations Capital letters are required, small letters are optional
Square Brackets [ ] Items in square brackets are optional.
Angle Brackets < > Items in angle brackets are command parameters.
Bar | Vertical bar means “OR”, select one of either item.
1|0|ON|OFF means 1 or 0 or ON or OFF acceptable
Asterisk * Required identifier for IEEE-488.2 common commands
Whole Numbers nn Whole numbers with no decimal point allowed
Decimals nn.nn Decimal numbers with optional decimal point
7.1.3. Examples of Alternative Forms of SCPI Command
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