iET PRS-330 series, Operation Manual, Page: 59 / 67

PRS-330 Series
APPENDIX A 47
Appendix A
SCPI COMMAND REFERENCE
SCPI is an acronym for “Standard Commands for
Programmable Instruments”. For additional in-
formation or an on-line copy of this standard, see:
http://www.scpiconsortium.org.
The IEEE 488.2 Standard was established in
1987 to standardize message protocols and
status reporting and to de
fi ne a set of common
commands for use on the IEEE 488 bus. IEEE
488.2 devices are supposed to receive messages
in a more
fl exible manner than they send. A
message sent from GPIB controller to GPIB
device is called: PROGRAM MESSAGE.
A message sent from device to controller is
called: RESPONSE MESSAGE. As part of the
protocol standardization the following rules were
generated:
(;) Semicolons separate messages.
(:) Colons separate command words.
(,) Commas separate data fi elds.
<nl> Line feed and/or EOI as last character
terminates a ‘program message’.
Line feed (ASCII 10) and EOI
terminates a RESPONSE MESSAGE.
(*) Asterisk de fi nes a IEEE 488.2 common
command.
(?)
Ends a query where a reply is expected.
SCPI builds on the programming syntax of IEEE-
488.2 to give the programmer the capability of
handling a wide variety of instrument functions
in a common manner. This gives all instruments
a common “look and feel”. SCPI commands are
not case-sensitive.
The portion of commands shown in capitals
denotes the abbreviated form of the keyword.
Either the abbreviated or whole keyword may
be used when entering a complete command.
There must be a space between the command
and a parameter or channel list. Multiple SCPI
commands may be concatenated together as a
compound command by using semicolons as
command separators.
Keywords shown inside braces [ ] are
defaults, and are optional when constructing a
PROGRAM MESSAGE.
Commands not recognized have no effect
on the unit’s operation and will set the
corresponding bits in the Standard Event
Status Register. SCPI commands that end with
a question mark ‘?’ are queries. All queries
should be followed by reading their response to
avoid data loss.
Semicolon ‘;’ is used to separate more
commands written on one line.
Terminators: For GPIB interface each
command line must end with line feed <lf>.
Response from the device also returns line feed
<lf>.