Table of Contents
Advertisement
3.6.4.3
QUERY INDICATOR
The question mark (?) following a keyword is a query indicator. This changes the command into
a query. If there is more than one keyword in the command, the query indicator follows the last
keyword. (e.g., VOLT? and MEAS:CURR?).
3.6.4.4
DATA
Some commands require data to accompany the keyword either in the form of a numeric value
or character string. Data always follows the last keyword of a command or query (e.g.,
VOLT:LEV:TRIG 14 or SOUR:VOLT? MAX
3.6.4.5
DATA SEPARATOR
Data must be separated from the last keyword by a space (e.g., VOLT:LEV:TRIG 14 or
SOUR:VOLT? MAX
ROOT SPECIFIER
MESSAGE UNIT SEPARATOR
DATA SEPARATOR
KEYWORD
KEYWORD SEPARATOR
KEYWORD
3.6.4.6
MESSAGE UNIT SEPARATOR
When two or more message units are combined in a program message, they must be separated
by a semicolon (;) (e.g., VOLT 15;MEAS:VOLT? and CURR 12; CURR:TRIG 12.5).
3.6.4.7
ROOT SPECIFIER
The root specifier is a colon (:) that precedes the first keyword of a program message. This
places the parser at the root (top left, Figure 3-18) of the command tree. Note the difference
between using the colon as a keyword separator and a root specifier in the following examples:
VOLT:LEV:IMM 16
3-58
DATA
CURR:LEV 3.5;:OUTP ON;:CURR?<NL>
FIGURE 3-19.
MESSAGE STRUCTURE
Both colons are keyword separators.
DATA
MESSAGE UNIT SEPARATOR
ROOT SPECIFIER
KEYWORD
QUERY INDICATOR
MESSAGE TERMINATOR
MESSAGE UNIT
BOP HIPWR 080709
Advertisement
Table of Contents
