Keithley 237 - Page 107

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SECTION2
Operation
Sweep
Operation
Operation
Overview
The basic steps to perform a sweep are as follows:
1.
Use
create to define the parameters
of
the
desired
waveform (paragraph 2.19).
2.
If
needed,
use
append
and/
or
modify to alter
the
ba-
sic sweep waveform (paragraphs
2.20
and
2.21).
3. Configure the triggers. Triggers
are
used
to
start
and
control a
sweep
(paragraph 2.22).
Paragraph 2.23 (Performing a
Sweep)
summarizes
the
fundamentals
of
performing a sweep. This
short
proce-
dure
ties together information previously presented
in
this section
(Section 2).
After a
sweep
is
run, test
data
is
stored
in
the
sweep
buffer. Recalling
data
from
the
sweep
buffer
is
explained
in
paragraph
2.24.
The
Source
Measure
Unit becomes a
more
powerful tool
when
combined
with
one
or
more
additional
Source
Measure
Units
for more complex test systems (such as
semiconductor characterization). Mult-unit operation
is
covered
in
paragraph
2.25.
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2.18
BASIC SWEEP WAVEFORMS
The six basic sweep waveforms
that
are available are
de-
scribed as follows:
Fixed Level
Sweep:
As
shown
in
Figure 2-31, this sweep
sources a fixed
de
level. The programmable parameters
of
this
sweep
include; bias, source level, delay,
number
of
measurement points,
and
source range.
When
this
sweep
is triggered
to
start,
the
output
will
go
from the bias level to
the
source level. The
duration
of this
sweep
is determined
by
the
number
of
measurement
points
(1
to 1000),
the
time period of
the
delay
and
the
measurement time. Notice
that
a delay precedes every
measurement. After
the
last measurement,
the
output
will
return
to
the
bias level.
Linear
Staircase
Sweep:
As
shown
in
Figure 2-32, this
sweep
steps from a
start
source value to
an
ending
source
value. The programmable parameters
of
this sweep
in-
clude;
start
level, stop level, step, delay,
bias~
and
source
range.
When
this sweep
is
triggered
to
start,
the
output
will
go
from
the
bias level to
the
start source level. The
output
will
then
change
in
equal steps until
the
stop source level
is
reached. The time
duration
at
each
step
of the
sweep
is
largely determined
by
the
programmed
delay. A meas-
urement
occurs after
the
delay
on
each step. After taking
the
last measurement
at
the
stop
source level, the
output
returns
to
the
bias level.
2-55