Agilent Technologies E1441A Command Fundamentals, Common Command Format, SCPI Command Format

Command Fundamentals

Common

Command

Format

Commands are separated into two types: IEEE 488.2 Common Commands and SCPI Commands.

The IEEE 488.2 standard defines the Common commands that perform functions like reset, self-test, status byte query, etc. Common commands are four or five characters in length, always begin with the asterisk character (*), and may include one or more parameters. The command keyword is separated from the first parameter by a space character. Some examples of common commands are shown below:

*RST *ESR 32 *STB?

SCPI

Command

Format

Command Separator

The SCPI commands perform functions such as making measurements, querying instrument states, or retrieving data. A command subsystem structure is a hierarchical structure that usually consists of a top level (or root) command, one or more low-level commands, and their parameters. The following example shows the root command CALibration and its lower-level subsystem commands:

CALibration :COUNt?

:SECure:CODe < new code> :SECure:STATe OFF ON, <code> :SECure:STATe?

:SETup < 0 1 2 3 . . . 84 :SETup?

:STRing < quoted string> :STRing?

:VALue < value> :VALue?

CALibration is the root command, COUNt?, SECure, SETup, SETup?, STRing and STRing? are second level commands, and CODE, STATe and STATe? are third level commands.

A colon (:) always separates one command from the next lower level command as shown below:

CALibration:SECure:STATe?

Abbreviated Commands

Colons separate the root command from the second level command (CALibration:SECure) and the second level from the third level (SECure:STATe?).

The command syntax shows most commands as a mixture of upper and lower case letters. The upper case letters indicate the abbreviated spelling for the command. For shorter program lines, send the abbreviated form. For better program readability, you may send the entire command. The instrument will accept either the abbreviated form or the entire command.

For example, if the command syntax shows FREQuency, then FREQ and FREQUENCY are both acceptable forms. Other forms of FREQuency, such as FREQU or FREQUEN will generate an error. You may use upper or lower case letters. Therefore, FREQUENCY, frequency, and FrEqUeNcY are all acceptable.

70 Agilent E1441A SCPI Command Reference Chapter 3