SCPI Command Structure

SCPI commands use the conventions described in this section.

SCPI commands are made up of nodes each separated by colon (:). Each node can have a long and a short form. For example, the following long form command: 

CONFigure:RFSA:GPRF:FREQuency

has the following short form: 

CONF:RFSA:GPRF:FREQ

The instrument will identify only the exact short form or the exact long form of a node, however the form is not case sensitive. The only purpose of upper and lower case characters in SCPI commands is to allow you to distinguish between the long form and short form.

You can mix the usage of short form and long form nodes by using short form in some nodes and long form in others. For example, the following two commands are both valid and identical to the instrument: 

CONF:RFSA:GPRF:FREQuency 
ConFigure:rfSA:GpRf:freq

However, the following command is not valid because Config is neither the long form nor the short form of CONFigure. 

Config:RFSA:GPRF:FREQuency
Note SCPI commands are not abbreviations. According to SCPI-99 rules, they are contractions of multiple words. For example, EATTenuation is a contraction of external attenuation.
Table 1. SCPI Command Conventions
Convention Description
Angle brackets <> Items within angle brackets are variable parameters.
Vertical bar | Vertical bars separate alternative parameters. For example, INTERNAL | EXTERNAL indicates that either INTERAL or EXTERNAL can be used as a parameter.
Square Brackets [ ] Items within square brackets are optional. The representation CONFigure:RFSA:GPRF:FREQuency[:CENTer] indicates that the node :CENTer may be omitted. A parameter within square brackets indicates that the specific parameter may be omitted.
Braces {} Braces indicate parameters that may be repeated zero or more times. It is used especially for showing arrays. The notation <A>{,<B>} shows that parameter A must be entered, while parameter B may be omitted or may be entered one or more times.