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NOTES: 1. The power supply is assumed to be operating in constant voltage mode.
2. The WAIT commands provide a method to synchronize multiple instruments to a common control
pulse. This example assumes BOP and a number of switching DVMs are connected to a Unit
Under Test (UUT). The DVMs are programmed to wait 1 millisecond after a high pulse is received
from the host computer, then take a few measurements. The same high pulse is applied to the Trig-
ger Input (pin 3 of the BOP Trigger Port); the negative-going edge of this pulse will cause the BOP
to increment the output to the next level. Thus, each time the host computer issues a positive
pulse, the BOP increments and the DVMs take measurements on the trailing (negative-going)
edge of the positive pulse. The positive pulse must be greater than 4 milliseconds in width for this
example to operate correctly.
3. The explanation below shows how each step of the list functions once the list is entered and
VOLT:MODE LIST (the last step) is executed.
list:cle
list:volt:apply level,.001,0
list:dwell:points?
list:wait:high 0
--- Host computer issues high pulse. Trigger input goes high and List proceeds to next point.
list:wait:low 0
--- Input Trigger goes low at trailing (negative-going) edge of pulse from host commuter and List
proceeds to next point. One millisecond after pulse issued, DVM takes measurements.
list:wait:high 1.1
--- Host computer issues another high pulse. Trigger input goes high and List proceeds to next
point.
list:wait:low 1.1
--- Input Trigger goes low at trailing (negative-going) edge of pulse from host computer and List
proceeds to next point. One millisecond after pulse issued, DVM takes measurements.
list:dwell:points?
list:wait:high 2.2.
--- Host computer issues another high pulse. Trigger input goes high and List proceeds to next
point.
list:wait:low 2.2
--- Input Trigger goes low at trailing (negative-going) edge of pulse from host computer and List
proceeds to next point. One millisecond after pulse issued, DVM takes measurements.
list:dwell:points?
list:repeat 6,7,3.3,4.4,5.5,6.6,7.7
list:count 2
list:dwell:points?
list:count:skip 10
curr 5;:outp on
--- Ensure Input Trigger is low.
VOLT:MODE LIST
FIGURE B-6.
USING LIST:WAIT COMMANDS TO CONTROL GENERATION OF A WAVEFORM MEASURED BY
MULTIPLE EXTERNAL DEVICES USING A SINGLE EXTERNAL PULSE
B-20
Clears the list.
Establishes the list as a voltage list, output set to 0V.
Returns 10. (Levels below 3 milliseconds use 10 points.)
Maintains output at 0V, waits for Input trigger high before proceeding.
Maintains output at 0V, waits for Input Trigger low before proceeding.
Sets output to 1.1V (next point in waveform), waits for Input Trigger high
before proceeding.
Maintains output at 1.1V, waits for Input Trigger low before proceeding.
Returns the current point location (6). (Used for list:repeat.)
Sets output to 2.2V (next point in waveform), waits for Input Trigger high
before proceeding.
Maintains output at 2.2V, waits for Input Trigger low before proceeding.
Returns the current point location (16).
Repeats step 6 and 7 (list:wait:high and list:wait:low), except each pair is
set to the voltage specified in the array. This adds 10 points to the list and
sets the output values of each pair to be 3.3V, 4.4V, 5.5V, 6.6V, 7.7V.
Implements the waveform through two loops of the data.
Returns 10.
Bypass the first step in the repeated points.
Set output on, output current to 5A.
Executes the above list. At each low transition of the trigger line the BOP
increases its output voltage in 1.1 volt increments. The time period for
each increment is controlled not by the internal clock of the BOP but
rather the high-to-low edge of the pulse from the host computer. The use
of LIST:WAIT:HIGH followed by LIST:WAIT:LOW ensures the BOP waits
for a high-to-low edge transition on the trigger input before increasing the
output.
BOP-1K 080709
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