Keithley 237 - Page 125

+2
VOLTS
Note: Entering a step value that is lower than the
resolution of the source range
will
result
with
the
message
"VALUE OUT OF
RANGE"
when
the pa-
rameters are saved. A step value of zero will
be
used.
The source
will
never exceed the level of the first
sweep point.
Note: The maximum step value is twice the
full
scale
range
of
the highest range used
in
generating the
sweep.
10.
Press ENTER The pulse
on
time will then be dis-
played.
If
the on time is presently set to
100msec,
the
following will be displayed:
00.100SEC
ONTIME
11.
To change the pulse on time
(00.001
to
65.000
sec-
onds), key-in the value
using the keypad. The fol-
lowing shows a keyed-in value of
200msec:
+.2
SECONDS
12.
Press ENTER. The programmed off time
will
be dis-
played. For example,
if
the off time is presently
1/2
second, the following
will
be displayed:
00.500
SEC
OFF TIME
13.
To change the off time, key-in the time value using
the keypad. The following shows a keyed-in value of
300msec:
+.3
SECONDS
14.
Press ENTER The bias level will then be displayed.
For example,
if
the bias is presently set to
OV,
the fol-
lowing
will
be displayed:
+0.0000
V
BIAS
15.
To change the bias level, key-in the value from the
keypad. The following shows a keyed-in bias level of
-1.25V:
-1.25
VOLTS
16.
Press ENTER The currently selected source range
will
be displayed. For example,
if
110V
range cur-
rently selected, the following
will
be displayed:
llO.OOV
RANGE
+
+
SECTION2
Operation
17.
To change the source range, use the
SELECT
buttons
to display the desired range. The following shows
the
11
V
range selected:
ll.OOOV
RANGE
NOTE: Selecting a fixed range that is lower than the
highest keyed-in source
or
bias value
will
result in
the message ''VALUE
OUT OF
RANGE"
when
the
parameters are saved.
In
this situation, the source
will default to
BEST
FIXED
range.
18.
Press ENTER The following message
will
be dis-
played:
SAVE?
ENTER/CANCEL
19.
Atthis point, the keyed-in parameters can be entered
and
saved,
or
canceled. Perform one of the following
steps:
A.
To enter
and
save the keyed-in parameters, press
ENTER The GENERATING SWEEP message
will
be displayed. Sweep
create will disable and
the Source Measure
Unit
will
return to the
source-measure display state.
B.
To cancel the keyed-in parameters, press CAN-
CEL.
Sweep
create
will
disable
and
the Source
Measure Unit
will
return to the source-measure
display state. The previously programmed
sweep parameters
will
prevail.
NOTE
The
on
and
off times for a pulse sweep define
the entire period
of
each pulse waveform. The
on
and
off times include the effects of integra-
tion rate, filter,
and
default delay.
If
the Source
Measure
Unit
is configured such that it cannot
run
fast enough to
output
pulses at the pro-
grammed
on
and
off times, the message
"PULSE
TIME
NOT
MET"
will
be displayed.
The sweep can be performed,
but
it
will not
conform to the programmed on
and
off times.
Speed
can be increased
by
using a faster inte-
gration rate, less filtering,
and
by
disabling
default delay. Note that the message ''PULSE
TIME
NOT MET" is always displayed
when
AUTORANGE is enabled (see paragraph
2.13).
2.19.9
Log
Staircase
Pulse
Sweep
Perform the following steps to create a sweep for a loga-
rithmic staircase pulse waveform (see Figure
2-36):
2-73