Keithley 237 - Page 130

SECTION2
Operation
NOTE:
The Q commands to create a sweep list (QO through Q5)
are explained in paragraph 2.19.3.
HP BASIC 4.0 Programming Example:
The following program will append a fixed level sweep
to a staircase sweep.
10 REMOTE716
20
OUTPUT 716; "F0,1X" Source V
Measure I
(sweep)
30
OUTPUT 716;
"BO,O,X" Set bias level to OV
40
OUTPUT716;
Create lin stair sweep
"Q1,1,10,1,0,500X"
list
50
OUTPUT716;
Append a fixed level
"Q6,2,0,300,5X"
sweep
60 END
Lines 10 through 40 create a sweep list for the linear stair-
case
sweep waveform. The staircase will start at 1 V and
step in 1V increments up to 10V. The programmed dwell
on each step is 1/2 second. Line 50 will append a fixed
level (2V, 5 points,
and 300msec delay) sweep to the stair-
case sweep.
Complete information on the IEEE-488 bus and these
commands can be found in Section 3 of this manual.
2.21 MODIFY SWEEP
The modify feature permits source level and delay time
changes to be made for any measurement point in the
currently defined sweep. This feature allows custom
shaped waveforms to be fabricated.
An example of a modified sweep is shown in Figure 2-45.
The linear staircase sweep waveform is modified as
shown to demonstrate the versatility of the modify fea-
2-78
+
+
ture. The first four measure points of the staircase are un-
changed. The fifth point is changed to the same level as
the fourth point (4V). The result is a staircase step that has
more than one measure point. This allows multiple meas-
urements to be performed on a single step of a staircase
waveform.
The rest of the sweep (points 6, 7 and 8) is
modified to step down to the bias level using a longer
dwell time on the steps.
General Modify Rules:
1. Enabling MODIFY displays the source value of the
first sweep point. Any sweep point can be displayed
with the rotary knob. SELECT~ and <IIIII SELECT tog-
gles
the display between the source and delay pa-
rameter for the displayed sweep point.
2. A
source value is modified as follows:
A.
Using the rotary knob, display the sweep point
to be modified.
B. Using the keypad, key in the new source value
and press ENTER.
C.
Using the SELECT buttons, display the desired
source range and press ENTER.
3. A
delay period is modified as follows:
A.
Using the rotary knob, display the sweep point
to be modified.
B. Using the keypad, key in the new delay period
and press ENTER.
4. Exit
the modify menu by again pressing MODIFY.
In many test situations, only minor modifications to a
sweep waveform that is already being used will be re-
quired.
Complex waveform fabrication will require a lit-
tle
more planning. The following hints may be helpful:
1. Sketch the waveform that you wish to fabricate. Indi-
cate
source levels, measure points and delay times.
2. Select
and define (CREATE) a standard sweep
waveform that will be the easiest to modify into your
custom waveform.
3.
Consider the value of appending one or more
waveforms to the one you just defined (see Append
Sweep; paragraph 2.20).
4.
With a good fundamental waveform defined, go
ahead and modify it as follows.