Section 4: Introduction to SCPI
Series 2230G Triple-Channel Power Supplies User's Manual
4-4
2230G-900-01 Rev. A / June 2018
Long-form and short-form versions
A SCPI command word can be sent in its long-form or short-form version. The command subsystem
tables in the
(on page 5-1) provide the long-form version. However, the
short-form version is indicated by upper case characters. The following are some examples:
:SYSTem:PRESet
Long-form
:SYST:PRES
Short-form
:SYSTem:PRES
Combination of long-form and short-form
Each command word must be in long-form or short-form, and not something in between. For
example,
:SYSTe:PRESe
is illegal and will generate an error. The command will not be executed.
The message unit
The simplest SCPI command is a single message unit consisting of a command header (or keywords)
followed by a message terminator. The message unit may include a parameter after the header. The
parameter can be numeric or a string. For example:
VOLTage 20<NL>
The following topics describe the parts of a SCPI command message in more detail.
Headers
Headers, also referred to as keywords, are instructions recognized by the power supply. Headers
may be either in the long form or the short form.
In the long form, the header is completely spelled out, such as VOLTage, STATus, and DELay.
In the short form, the header has only the first three or four letters. Examples of four-letter short form
commands are
VOLT
and
STAT
. If the fourth letter of the long form is a vowel (for example,
DELete
),
the short form only contains three letters (
DEL
).
Queries
You can use a query to determine the present value of the parameters of the command or to get
information from the instrument. Following a header with a question mark turns it into a query, for
example:
VOLTage?
VOLTage:PROTection?
If a query contains a parameter, place the query indicator at the end of the last header, for example:
VOLTage:PROTection? MAX