Interface Functions; Introduction; Interface Capabilities; Addressing - HP 54501A Programming Reference Manual

Interface Functions
2
Introduction
This section describes the interface functions and
some general
concepts
of
the
HP-IB. In
general,
these functions are defined
by IEEE
488.1.
They deal with general
bus
management
issues,
as
well
as messages
which
can be sent over the bus
as
bus
commands.
Interface
Capabilities
The
interface capabilities of the HP
54501A,
as
defined by
IEEE
488.1
are
SH1,
AH1,
T5, L4,
SRI, RL1,
PP1,
DC1, DT1,
CO,
and
E2.
Command and
Data Concepts
The HP-IB
has
two modes of operation: command mode and
data
mode.
The
bus
is
in
command mode
when the
ATN
line
is true. The command
mode
is
used to send
talk and
listen addresses and various bus
commands,
such
as a
group execute trigger
(GET). The bus is in the data mode when
the
ATN
line is
false.
The
data mode
is
used to convey device-dependent
messages across
the
bus.
The device-dependent
messages
include all
of
the instrument command and responses found
in chapters 5 through 17
of
this
manual.
Addressing
By using the
front-panel controls,
the
instrument
can be placed in
either
talk-only mode or addressed (talk/listen) mode (see your front-panel
reference). Talk-only mode should be
used
when you want the instrument
to talk directly to
a
printer without
the aid
of
a
controller.
Addressed
mode
is
used when
the
instrument will operate in conjunction with
a
controller.
When the instrument
is
in the addressed mode, the following
is
true:
HP 54501A
Programming
Interface Functions
2-1