Agilent Technologies 54645A Manual de Instruções descarregar pdf (Página 59)

Subsystem Commands

Subsystem commands are grouped together under a common node of the

command tree, such as the TIMEBASE commands. Only one subsystem may

be selected at any given time. When the instrument is initially turned on, the

command parser is set to the root of the command tree, therefore, no

subsystem is selected.

Tree Traversal Rules

Command headers are created by traversing down the command tree. A legal

command header from the command tree would be :ANALOG1:RANGE. This

is called a compound header. A compound header is a header made of two or

more mnemonics separated by colons. The mnemonic created contains no

spaces. The following rules apply to traversing the tree:

•

A leading colon or a <program message terminator> (either an <NL> or

EOI true on the last byte) places the parser at the root of the command

tree. A leading colon is a colon that is the first character of a program

header.

•

Executing a subsystem command places you in that subsystem until a

leading colon or a <program message terminator> is found. In the

Command Tree, use the last mnemonic in the compound header as a

reference point (for example, RANGE). Then find the last colon above that

mnemonic (ANALOG<n>). That is the point where the parser resides. Any

command below that point can be sent within the current program

message without sending the mnemonics that appear above them (for

example, OFFSET).

Examples

The OUTPUT statements in the examples are written using HP BASIC 5.0.

The quoted string is placed on the bus, followed by a carriage return and

linefeed (CRLF).

Example 1:

OUTPUT 707;":ANALOG1:RANGE 0.5 ;OFFSET 0"

The colon between ANALOG1 and RANGE is necessary because

ANALOG1:RANGE is a compound command. The semicolon between the

RANGE command and the OFFSET command is the required program

message unit separator. The OFFSET command does not need ANALOG1

preceding it, since the ANALOG1:RANGE command sets the parser to the

ANALOG1 node in the tree.

Programming and Documentation Conventions

The Command Tree

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Agilent Technologies 54645A Manual de Instruções Página 59