KEPCO KIT 219-0533, BOP 1000W Firmware Upgrade - Manual (Page 12)

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B.34.3 [SOURce:]LIST:WAIT:LOW COMMAND
LIST:WAIT:LOW
Syntax: Short Form: LIST:WAIT:LOW value
Long Form: LIST:WAIT:LOW value
where:
= programmed current (Amps) for current list, or programmed voltage (Volts) for voltage list.
Description: Waits for the trigger input to go low before advancing to next step. When the command is executed the output
is immediately set to the . Pins 1 (GND) and 3 of the Trigger Port are used as the input trigger. If the trigger
input is low (TTL logic 0 or short-circuit) and a wait time has been established by LIST:SET:WAIT, the step is imme-
diately skipped. If the trigger input is high (TTL logic 1 or open circuit), the unit will proceed to the next step when
either a) the trigger input goes low or b) the wait time expires (non-zero wait values only), whichever comes first. If
the wait time is 0, the unit must wait until the trigger input goes low before proceeding to the next step.
In all cases, the trigger input must be high or low for at least 2 microseconds to be considered stable. This 2 micro-
second delay provides a noise filter to insure only a level causes the output change.
This command must be preceded by LIST:CURR or LIST:VOLT command, otherwise a -221 “Settings Conflict”
error results. The entries of the dwell list must match the values in the current or voltage list, otherwise a -236 “Lists
Unbalanced” error results. (See Figures B-2A and B-2B.)
FIGURE B-2C. USING LIST:WAIT COMMANDS TO CONTROL GENERATION OF A WAVEFORM MEASURED BY
MULTIPLE EXTERNAL DEVICES USING THE LOW-GOING LEADING EDGE OF AN EXTERNAL PULSE
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 low-going edge is received from the host computer, then
take a few measurements. The same low-going edge is applied to the Trigger 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 can be very short (less than 2
microseconds) with this functionality.
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 Clears the list.
list:volt:apply level,.001,0 Establishes the list as a voltage list, output set to 0V.
list:wait:ledge 0 Maintains output at 0V, waits for Input trigger to have a high to low edge before pro-
ceeding.
--- Host computer issues high pulse. 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 measure-
ments.
list:dwell:points? Returns the current point location (3). (Used for list:repeat.)
list:repeat 1,2,1.1,2.2,3.3,4.4,5.5,6.6,7.7 Repeats step 1 and 2 (list:volt:apply lev and list:wait:ledge), except each pair is set
to the voltage specified in the array. This adds 14 points to the list and sets the out-
put values of each pair to be 1.1V, 2.2V, 3.3V, 4.4V, 5.5V, 6.6V and 7.7V.
list:count 2 Implements the waveform through two loops of the data.
curr 5;:outp on Set output on, output current to 5A.
VOLT:MODE LIST Executes the above list. At each high-to-low transition of the Trigger Port input, the
BOP increases its output voltage in 1.1 volt increments. The duration of each incre-
ment is not controlled by the internal clock of the BOP, but instead by the high-to-low
edge of the pulse from the host computer.