User`s guide

Remarks
This command has no effect if the sample count is 1 (see SAMPle:COUNt).
After setting the sample count, sample source, and the sample interval or
trigger delay time, you must place the instrument in the "wait-for-trigger"
state using the INITiate or READ? command. A trigger will not be accepted
from the selected trigger source (see TRIGger:SOURce command) until the
instrument is in the "wait-for-trigger" state.
The instrument sets the sample source to "IMM" after a Factory Reset (
*RST command) or an Instrument Preset (SYSTem:PRESet command).
It is recommended that all triggered measurements be made using an
appropriate fixed manual range. That is, turn autorange off
(SENSe:<function>:RANGe:AUTO OFF), or set a fixed range using the
SENSe:<function>:RANGe, CONFigure, or MEASure command.