4349B
T
o
Set
the
Contact
Check
The
Cont Check
annunciator(
9
) tells
the
current
contact
check
status
.
T
o
set
or
abort
the
contact
check function:
Note
Before
performing
the
contact check,
perform the
OPEN correction
to measure
the
reference
value
of the
contact check.
Note
The
contact
check
feature
of
the 4349B
discriminates Contact/NO
Contact
based
on the
dierence in
capacitance between
when the
DUT
is
connected
and
when it
is not
connected (Open).
Therefore,
if
the
change
of
capacitance
between
those
two
dierent states
is not
enough, the
discrimination
may
fail.
T
o
enable
or
disable
the
contact
check
function:
1.
Press
.
2.
Select
ON/OFF
using
or and
press
to
select.
3.
Select
On
or
Off
using
or ,
and
press
to
exit
to
the
previous
display
.
4.
Select
Exit
using
or ,
and press
to
exit.
5.
The
Cont
Chk
annunciator(
9
)
turns
ON
if
the
contact
check
function
is enabled.
In
the
case
of
the
contact
check
function
is
enabled,
N.C.
(No-Contact)
will be
displayed
when
the
contacts
between
dut
and
xture
are
open.
See
\Contact
Check
Eective Range
"
in
Chapter 8 for the contact check eective range
.
To perform the contact check eectively
, note the following:
Connect the coaxial cable as close to the DUT
as possible
.
If the judgment result is Contact when the DUT is
not connected due to variation in residual
capacitance of the xture or cable used for the automated test
equipment, set an Oset
value for the Limit value to provide a stricter discrimination criterion.
For the principle of operation of the contact check, refer to Chapter 3 \Principle of Operation."
Contact check compares a measured capacitance data of dut with a limit data. Interpretation
of the limit data and the measured capacitance data of the dut are shown below.
2-8 Operating the 4349B