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6.8
Coupler
and
Interface
Electronics
Troubleshooting
The
following
paragraphs
describe
some
of
the
methods
for
isolating
a
problem
to
a
given
plug-in
module.
For
coupler
bus
signal
line
information,
refer
to
Table
4-1
and
the
10740A
unit
manual.
6.9
10745A
HP-IB
INTERFACE
TROUBLESHOOTING.
The
10745A
interface
transfers
instructions
from
a
calculator/controller
to
the
10740A
Coupler
backplane
bus. The
instructions
are
examined
by
each
of
the modules
plugged
into
the
coupler
for
applicability
to
a
specific
module.
These
modules
function
according
to
the
specific
instruction
and
in
some
cases
trans-
fer
data
back
to
the
controller
via
the
coupler
bus
and
the
10745A
interface
module.
If
the
sys-
tem
does
not
respond
to
any
instructions
and
the
controller
diagnostics
verify
proper
controller
operation,
either
the
10745A
module
i s
the
source
of the
trouble
or
another
module
is
prevent-
ing
the
backplane
handshake
lines
from
operating.
The
10745A
has
two
LED
indicators
near
the
front
edge
of the
circuit
board.
One
signifies
that
the
10745A
has
been
addressed
to
talk
by
the
HP-IB
controller;
the
other
indicator
signifies
that
the
10745A
has
been
addressed
to
listen.
Check
these indicators
to
verify
correct
address-
ing
by
the
controller
and
to
verify
that
the
10745A
address
switches
are
properly
set.
6.10
10746A
BINARY
INTERFACE.
The
10746A
interface
transfers
instructions
and
data
between
the
10740A
Coupler
backplane
bus
and
a
system
controller
(usually
a
computer).
If
communication
between
these
devices
does
not take
place and
the
controller
diagnostics
verify
proper
operation
of
the
controller,
either
the
10746A
is
the
source
of
the
problem
or
an-
other
module
is
preventing
the
backplane
handshake
lines
from
operating.
The
10746A
contains
one
LED
indicator
to
signify that
the
board
i s
in
the
data
mode
of
oper-
ation.
Be
sure
to
observe
that
power
is
available.
If
the
problem
appears to
be
within the
10746A
module,
check
that
the
controller
applies
a
"command"
signal
to
the
10746A
prior
to
replacing
the
module.
6.11
10755A
COMPENSATION
INTERFACE.
The
10755A,
in
response
to
coupler
backplane
bus
instructions,
transfers
velocity-of-light
compensation
data
to
the
coupler
backplane
bus
data
lines.
The
10755A
converts
the
BCD
compensation
data
from
a
10756A
Manual
Com-
pensator
or
5510A
OPT
010
Automatic
Compensator
to
binary
data
for
placement
on
the
coupler
backplane
bus.
If
the
compensation
number
is
erroneous,
check
the
compensator
for
proper
operation
according
to
the
information
given in
the
separate
compensator
operating
and
service
manual.
If
compensation
data
i s
not
placed
o n
the
coupler
backplane
bus
upon
command,
the
10755A
module
is
probably
the
source
of
the
trouble.
6.12
10760A
COUNTER
TROUBLESHOOTING.
The
10760A
accepts
a
reference
signal
from
the
laser
head
and
a
measurement
signal
from
the
receiver
in
a
given
measurement
axis.
LED
indicators
on
the
10760A
circuit
card
light
when
the
reference
and
measurement
signals
are
present.
Note,
however,
that
these
indicators
will
light
even
if
the
10760A
card
is
not
plugged
into
the
10740A
Coupler.
They
obtain
operating
power
from
the
connector
o n
the
front
edge
of the circuit
card.
After
verifying
that
the
proper
reference
and
measurement
signals
(approximately
2MHz,
differ-
ential)
are
available
at
the
circuit
inputs,
you
can
assume
a
malfunction
of
the
10760A
if
it
fails
to
perform
any
of
its normal
operating
functions.
Most
systems
contain
more
than
one
measurement
axis
and,
consequently,
more
than
one
10760A
Counter.
If
trouble
is
suspected
with
a
counter
card, exchange
it
with
another
card
in
the
sys-
tem
to
verify
the
suspected
malfunction.
(Remember
to
change
the
address
jumper
and
any
other
jumpers
that
may
be
set
differently.)
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Table of Contents
Troubleshooting
