User`s guide

6 SCPI Command Reference
114 N9340A User’s Guide
SCPI Language Basics
Standard Commands for Programmable Instruments
(SCPI) 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.
Table 1 Common Terms used in this Book
Terms Description
Controller: Any computer used to communicate with an instrument. A controller
can be a personal computer (PC), a minicomputer, or a plug-in card in a
card cage. Some intelligent instruments can also function as
controllers.
Instrument: Any device that implements SCPI. Most instruments are electronic
measurement or stimulus devices, but this is not a requirement.
Similarly, most instruments use a GPIB, RS-232, or USB interface for
communication. The same concepts apply regardless of the instrument
function or the type of interface used.
Command: An instruction. You combine commands to form messages that control
instruments to complete a specified task. In general, a command con-
sists of mnemonics (keywords), parameters and punctuation.
Query: A special type of command. Queries instruct the instrument to make
response data available to the controller. Query keywords always end
with a question mark (?).