SCPI Command Introduction 
  Copyright©  Itech Electronics Co., Ltd.  1
Chapter1 SCPI Command Introduction 
1.1 Overview 
SCPI is short for Standard Commands for Programmable Instruments which 
defines a communication method of bus controller and instrument. It is based 
on ASCII and supply for testing and measuring instruments. SCPI command is 
based  on hierarchical architecture which  also known as  tree  system. In this 
system, Relevant Command is returned to a common node or root, so that a 
subsystem is formed. 
A part of OUTPut subsystem is listed below: 
OUTPut: 
SYNC {OFF|0|ON|1} 
SYNC: 
MODE {NORMal|CARRier} 
POLarity {NORMal|INVerted} 
OUTPut is the root class keyword, SYNC is the second keyword, MODE and 
POLarity are the third keyword. Colon(:) is used for separating the command 
keyword and the next level keyword. 
1.2 Command Type of SCPI 
SCPI has two types of commands, common and subsystem. 
  Common commands generally are not related to specific operation but to 
controlling overall
.
instrument functions, such as reset, status, and 
synchronization. All common
 
commands consist of a three-letter mnemonic 
preceded by an asterisk: *RST *IDN? *SRE 8. 
  Subsystem commands perform specific instrument functions. They are 
organized into an inverted tree structure with the "root" at the top. The 
following figure shows a portion of a subsystem command tree, from which 
you access the commands located along the various paths. 
 
 
Multiple commands in a message 
Multiple  SCPI  commands  can  be  combined  and  sent  as  a  single 
message  with  one  message  terminator.  There  are  two  important