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4.3.4
Note
in
the table the
column
headed
"ADDRESS SWITCH
SETTING".
It
illustrates
the positions of
switches
A1
to
A5
for
each
number
address
listed
in
the far
right
column.
To
set the
GPIB
address,
simply
select
the desired
decimal
address
for
the
counter,
refer
to
the
table,
and
set
the
switches on
the address selector
to
the
corresponding pattern
shown
in
the
column.
4.3.5
Once
an address has
been
assigned
and
stored, the controller
may
then
address the
1994
as a talker
/listener
by transmitting
the appropriate
ASCII character on
the data
lines.
The
"DATA
LINES" column
of the table
shows
the
7-bit
binary
codes
for
every
talk/listen
address assigned
to
the counter.
The
controller transmits these
codes
to
the
counter
to establish
its
talker/listener status.
4.3.6
Note
also
in
the table that there are
two
address codes
for
each
GPIB
address
number.
Each code
represents a
different
ASCII
character.
For example,
if
an
address
of 02
is
assigned
to
the counter, the
talk
address
is
the
ASCII
character
B
and
the
listen
address'
is
the
ASCII character
".
The
only
difference
in
the binary
code
in
each
case
is
the state of data
lines
D6
and D7.
4.3.7
The
counter's
GPIB
address can be displayed
in
decimal form
using
key
sequence
SHIFT
RECALL ADDR.
If
the
1994's
bus address
is
changed,
the
previous
key
sequence must be repeated
to
display the
new
address.
Press the
CONTINUE
key
to
return the
1994
to
the
measurement mode.
4.3.8
The
rear-panel
GPIB
switch
bank
provides
a "Talk-Only"
selector
switch
(see
Subsection
4.6.2).
4.3.9
The
1
994
is
preset at
GPIB
address
03
when
shipped.
4.4
GPIB
FUNCTIONAL
CHECK
4.4.1
Introduction
4.4. 1.1
The
following
procedure
verifies the 1994's
capability
to
accept, process,
and
transmit
GPIB
messages.
Complete
a satisfactory
check
of
the counter
under
local
control before starting
this
procedure
(see
Subsection
2.9).
4.4.1.2
Successful
completion
of the
GPIB
check
indicates that the counter's
GPIB
interface
is
operating properly.
4.4.1.3
For
recommended
test
equipment
use
a
Hewlett-Packard Model HP-85
GPIB
controller
with I/O
ROM
in
a drawer.
It
is
assumed
that the
select
code
for
the
controller I/O port
is
7
and
the
GPIB
address of
the
counter
is
15.
NOTE;
If
any
other
controller or
selected/GPIB
address
combination
is
used, the
GPIB
commands
in
the following
procedure
will
require
change.
4. 4.
1.4
Connect
the controller to the
GPIB
interface
of
the
counter
using a
standard
GPIB
cable.
No
connection should be
made
to Inputs
A,
B, or
C.
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