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Getting Started
3.4
Card
connections
Each
card designed
for the
Model
707A
is
configured
as
an
8 -row by
12-
column
matrix.
The rows
are
lengthened by
adding
columns from
other cards (of the
same model num-
ber).
Connections
for
row
expansion
are usually
internal to
the
mainframe,
either
through
the
analog backplane
buses or
with
user- installed
jumpers,
depending
on
the card
model.
Rows
can
also
be
expanded
across
mainframe
boundaries,
either
in
a master/slave or stand-alone/stand-alone configu-
ration. In
a master/slave configuration
of
up
to five
main-
frames,
the
rows
are
extended
to
360 columns maximum.
(Paragraph
3.5
describes master/slave expansion.)
Expansion
of
rows
leads
to
a
long,
narrow
matrix.
If
your
application requires
few
instruments
and
many DUTs,
con-
nect the instruments
to
rows
(up
to
8)
and
the
DUTs
to col-
umns
(up
to
72
with
6
cards).
This connection
scheme
is
optimum
because
the
row-column
path has only
one
cross-
point,
as
shown
in
Figure
3-4,
1
2
3
4
5
6
7
8
9
10
11
12
Note
;
One
crosspoint closure yields
a row-column
path.
Selecting the
row
connections
for
instruments
is
important
with cards
designed
for
multiple
applications.
Using
the
Model 7072
as
an example,
the
recommended
connections
are as
follows:
•
Rows
A
and
B
(low
current)
—
Picoammeters,
electrometers.
•
Rows
C
through
F
(general
purpose)
—
DMMs,
sources.
•
Rows
G
and
H
(C-V
characteristics)
—
C-V
analyzers.
An
alternate
connection
scheme
of
the long,
narrow
matrix
has
all
connections on
the
columns,
both instruments
and
DUTs.
This
is
done
when
the
series
of
tests
requires
a
large
number
of instruments and
DUTs,
with only a
few
signals
for
each
test.
As
seen
in
Figure
3-5,
with
two
cards,
two
cross-
point relays
must
be
closed
to
complete
a path
from column-
column
(a safety benefit
when
sourcing). Paths
with multiple
crosspoints
have
additional
path
resistance
and
contact
potential
than
single crosspoint paths.
Crosspoint
programming becomes more complex
with
column-column
paths because of
the
number
of
possible
paths for large matrices
and
the
choice of
rows
to
complete
the
path.
(See Table
3-1.)
The row
completion
choice
for
column-column
paths
on
multiple application cards follows
the
recommendations
given previously
for
row-column
paths.
That
is,
with
a
Model 7072
card,
close a crosspoint
relay
in
row
A
or
B
for
low
current applications,
row
C, D, E,
or
F
for
general
pur-
pose
switching,
and
row F
or
G
for
C-V
switching.
Figure 3-4
Connecting
instruments
to
rows
3-8
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