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5.1 SCPI Brief Introduction
SCPI (Standard Commands for Programmable Instrument) is an ASCII- based instrument
command language designed for test and measurement instruments, with the goal of reducing
automatic test equipment (ATE) program development time. SCPI accomplishes this goal by
providing a consistent programming environment for instrument control and data usage. This
consistent programming environment is achieved by the use of defined program messages,
instrument responses, and data formats across all SCPI instruments. By providing a consistent
programming environment, replacing one SCPI instrument with another SCPI instrument in a
system should require less effort than with non- SCPI instrument.
SCPI is not a standard which completely provides for interchangeable instrumentation. SCPI
helps move toward interchangeability by defining instrument commands and responses, but not
functionality, accuracy, resolution, and so forth.
5.1.1 Basic Knowledge Requirement
Programming with SCPI requires knowledge of:
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Computer programming languages, such as C or C++.
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The language of your instrument. A HAS Series spectrum analyzer employs SCPI as its
programming language.SCPI.
5.1.2 Command Syntax
Command syntax includes standard notations and statement rules.
Command Statement Rules Overview
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Command statements read from left to right
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Use either long form or short form of keywords, but do not use both
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No separating space between the keywords, only use a colon to separate keywords of
different levels
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Always separating a keyword from a variable with a space
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Always separating a variable from its unit with a space (if variable has a unit)
5.1.3 Standard Notations
A command consists of mnemonics (keywords), parameters and punctuation. Before you start to
program your analyzer, familiarize yourself with the standard notation of each of them.
Keywords
Many commands have both a long and a short form: use either one. (a combination of the two is
not allowed). Consider the: FREQuency command for example:
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Short form : FREQ
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Long form : FREQuency
SCPI is not case sensitive, so fREquEncy is just as valid as FREQUENCY, but FREQ and
FREQUENCY are the only valid forms of the FREQuency command. In this documentation, upper
case letters indicate the short form of the keyword. The upper case and lower case letters indicate
the long form of the keyword.
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