HP 8753D - Page 625

A
TN (Attention)
The active
controller uses
this line
to dene
whether
the
information on
the data
bus is
command-oriented or
data-oriented.
When this
line is
true (low),
the bus
is in
the
command
mode,
and the
data lines
carry bus
commands
.
When
this
line is
false (high),
the bus
is in
the
data
mode
,
and
the
data
lines carry
device-dependent instructions
or data.
SRQ
(Service Request)
This line
is set
true
(low)
when
a
device
requests
service
and
the active
controller
services
the
requesting
device
.
The
network
analyzer can
be
enabled
to
pull
the
SRQ
line
for
a
variety
of reasons
such
as
requesting
control
of
the
interface
,
for
the purposes
of
printing,
plotting,
or
accessing
a
disk.
REN
(Remote Enable)
This line
is
used
exclusively
by
the
system
controller
.
When
this
line
is
set
true
(low),
the
bus
is
in
the
remote
mode
,
and
devices
are
addressed
by
the
controller
to
either
listen
or
talk.
When
the
bus
is
in
remote
mode
and
a
device
is
addressed,
it
receives
instructions
from
the
system
controller
via
HP-IB
rather
than
from
its
front
panel
(pressing
4
LOCAL
5
returns
the
device
to
front-panel
operation). When
this
line
is
set
false
(high),
the
bus and
all of
the
connected
devices
return
to
local
operation.
EOI (End
or Identify)
This line
is
used
by
a
talker
to
indicate
the
last
data
byte
in
a
multiple-byte transmission,
or by
an
active
controller
to
initiate
a parallel-poll
sequence.
The
analyzer
recognizes
the
EOI
line
as a
terminator,
and
it
pulls
the
EOI
line
with
the
last
byte
of
a
message
output
(data,
markers
,
plots
,
prints
,
error
messages).
The
analyzer
does
not
respond
to
parallel
poll.
HP-IB
Requirements
Number
of
Interconnected Devices:
15 maximum.
Interconnection
P
ath Maximum
Cable Length:
20
meters
maximum
or
2
meters
per
device
(whichever is
less).
Message
Transfer
Scheme: Byte
serial, bit
parallel a
synchronous
data
transfer
using
a 3-line
handshake system.
Data Rate:
Maximum
of
1
megabyte-per-second
over
the
specied distances
with
tri-state
drivers
.
A
ctual
data rate
depends on
the transfer
rate
of
the
slowest
device
connected
to
the bus
.
Address Capability:
Primary addresses: 31 talk, 31 listen. A
maximum of 1 talker and 14 listeners can be
connected to the interface at given time
.
Multiple-Controller Capability:
In systems with more than one controller (like
this instrument), only one controller can be
active
at any given time
. The active controller
can pass
control to another controller
, but only
the system controller can assume unconditional
control. Only one system controller is allowed.
Compatible Peripherals 11-17