SCPI Command Introduction 
  Copyright©  Itech Electronics Co., Ltd.  4
 
 
The Message Unit 
The simplest SCPI command is a single message unit consisting of a command 
header (or keyword) followed by a message terminator. The message unit may 
include  a  parameter  after  the  header.  The  parameter  can  be  numeric  or  a 
string. 
ABORt<NL> 
VOLTage 20<NL> 
Headers 
Headers,  also  referred  to  as  keywords,  are  instructions  recognized  by  the 
instrument. 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, such 
as VOLT, STAT and DEL. 
Query Indicator 
Following  a  header  with  a  question  mark  turns  it  into  a  query  (VOLTage?, 
VOLTage:PROTection?).  If  a  query  contains  a  parameter,  place  the  query 
indicator at the end of the last header(VOLTage:PROTection?MAX). 
Message Unit Separator 
When two or more message units are combined into a compound message, 
separate the units with a semicolon (STATus:OPERation?;QUEStionable?). 
Root Specifier 
When it precedes the first header of a message unit, the colon becomes the 
root specifier. 
Message Terminator 
A terminator informs SCPI that it has reached the end of a message. Three 
permitted message terminators are: 
  newline (<NL>),decimal 10 or hexadecimal 0X0A in ASCII. 
  end or identify (<END>) 
  both of the above (<NL><END>). 
In the examples of this guide, there is an assumed message terminator at the