Keysight Truevolt Series Operating And Service Manual page 306

MAX selects 1 billion readings. However, when pretrigger is selected, the maximum is 50,000 readings
l
( without the MEM option) or 2,000,000 readings ( with the MEM option).
This parameter is set to its default value after a Factory Reset (*RST) or Instrument Preset
l
(SYSTem:PRESet).
SAMPle:COUNt:PRETrigger {< count >|MIN|MAX|DEF}
SAMPle:COUNt:PRETrigger? [{MIN|MAX|DEF}]
Allows collection of the data being digitized before the trigger. Reserves memory for pretrigger samples
up to the specified number of pretrigger samples.
It is recommended that all triggered measurements be made using an appropriate fixed
manual range. That is, turn autorange off
a fixed range using the SENSe:<function>:RANGe, CONFigure, or
Parameter
0 to 1,999,999. Default: 0.
Configure AC voltage measurements using the 100 V range. Set the sample count to 10,000 and the pre-
trigger sample count to 5000 (5000 samples are taken before the trigger, and 5000 after). The trigger
occurs when the input signal reaches 0.75 volts.
CONF:VOLT:AC
VOLT:AC:RANG 100
SAMP:COUN 10000
SAMP:COUN:PRET 5000
TRIG:SOUR INT
TRIG:LEV 0.75
INIT
Applies only to the 34465A and 34470A.
l
Pretrigger applies to all measurement functions except CONTinuity and DIODe test.
l
Use SAMPle:COUNt
l
to set the number of pretrigger samples to take.
For example, with a sample count of 50,000, and a pretrigger sample count of 20,000, up to 20,000
samples are taken before the trigger, then 30,000 samples are taken after the trigger occurs.
The sample count and pretrigger count do not affect when the trigger occurs. If the memory allocated
for pretrigger samples fills up, the oldest readings are discarded. In the example above, the 20,000
most recent pretrigger samples are saved, even if more than 20,000 samples occur before the trigger.
If the trigger occurs before the pretrigger count is satisfied, only the actual pretrigger samples taken
are saved.
In all cases, after the trigger is received, only sample count minus specified pretrigger count readings
are taken. In this example, if the trigger occurs after 5 pretrigger samples have been taken (instead of
the specified 20,000), only 30,000 post-trigger samples are taken. This is because memory was
reserved for 20,000 pretrigger samples.
If a trigger occurs during a measurement, that measurement is considered to be a pretrigger sample.
l
Keysight True volt Series Operating and Service Guide
to set the total number of samples to take, then use SAMPle:COUNt:PRETrigger
SCPI Programming Reference
(SENSe:<function>:RANGe:AUTO
Typical Return
+999999
OFF), or set
MEASure command.
307