HP 3468A - 3468 A HP-IL Loop Capabilities

Normally
only
one
message
is
in
transit
around
the
loop
at
any
given
time.
In
general,
when
a
device
sources
a
message
it
waits
until
the
message
goes
com-
pletely
around
the
loop
and
returns
before
transmitting
the
next
message.
This
is
part
of
a
process
called
loop
handshaking
and
guarantees
that
talkers
and
con-
trollers
do
not
send
messages
faster
than
other
devices
can
accept
them.
It
also
provides
an
excellent
error-checking
capability.
Each
message
must
pass
through
each
device.
When
a
device
receives
a
message,
it
does
not
pass
it
on
to
the
next
device
until
it
is
ready
to
receive
the
next
message.
Consequently,
when
the
message
returns
to
the
sourcing
device,
it
knows
for
certain
that
all
devices
in
the
loop
have
received
the
message
and
are
ready
for
the
next.
3468A
Loop
Capabilities
The
following
table
lists
the
HP-IL
functional
subsets
that
the
3468A
responds
to
and uses.
R
The
3468A
handshakes
as
a
receiver
D
Handshakes
as
a
driver
to
the
next
device
AH
Handshakes
as an acceptor
SH1
Handshakes
as
a
source
T1,2,3,5,6
Basic
Talker,
Send
Status,
Send
Device
ID,
Talk
Only,
and
unad-
dressed
as
a
Talker
when
addressed
to
Listen
TEO
No
extended
Talker
capability
L1,3
Basic
Listener
and
unaddressed
to
Listen
when
addressed
to
Talk
LEO No extended Listener capability
co
The
3468A
cannot
serve
as
a
controller
AAI
Can
be
autoaddressed
by
the
controller
AEO
No
extended
addressing
capability
AMO
No
multiple
addressing
capability
DC2
The
3468A
responds
to
a
Device
Clear
and
Selected
Device
Clear
DT1
The
3468A
responds
to
a
Device
Trigger
RL2
Basic
Remote,
Local,
and
Local
Lockout
capability
SR2
Basic
Service
Request
and
Asynchronous
Service
Request
capabili-
ty
PPO
The
3468A
does
not
respond
to
a
parallel
Poll
MS1
The
3468A
does
have
a
manual
Service
Request
PDO
The
3468A
does
not
have
a
power-down
capability
DDO
The
3468A
does
not
implement
device
dependent
Talker
or
Listener commands
100