Agilent Technologies 665xA, 664xA Parts of a SCPI Message, 1.Command Message Structure, Headers

	Figure 2-1. Command Message Structure
The basic parts of the message in Figure 2-1 are:
Message Component	Example
Headers	VOLT LEV PROT CURR
Header Separator	The colon in VOLT:LEV
Data	4.5 4.8
Data Separator	The space in VOLT 4. 5 and PROT 4. 8
Message Units	VOLT:LEV 4.5 PROT 4.8 CURR?
Message Unit Separator	The semicolons in VOLT: LEV 4. 5; and PROT 4. 8;
Root Specifier	The colon in PROT 4. 8; : CURR?
Query Indicator	The question mark in CURR?
Message Terminator	The <NL> (newline) indicator. Terminators are not part of the SCPI syntax.

Parts of a SCPI Message

Headers

Headers (which are sometimes known as "keywords") are instructions recognized by the power supply interface. Headers may be either in the long form or the short form.

Long Form	The header is completely spelled out, such as VOLTAGE STATUS DELAY.
Short Form	The header has only the first three or four letters, such as VOLT STAT DEL.

Short form headers are constructed according to the following rules:

• If the header consists of four or fewer letters, use all the letters. (DFI DATA)

•If the header consists of five or more letters and the fourth letter is not a vowel (a,e,i,o,u), use the first four

letters. (VOLTage STATus)

•If the header consists of five or more letters and the fourth letter is a vowel (a,e,i,o,u), use the first three letters.

(DELay CLEar)

You must follow the above rules when entering headers. Creating an arbitrary form, such as QUEST for QUESTIONABLE, will result in an error. The SCPI interface is not sensitive to case. It will recognize any case mixture, such as VOLTAGE,

Voltage, Volt, volt.

Note Shortform headers result in faster program execution.

Remote Programming 11