User`s guide

Remarks
You must select the limit math function (CALC:FUNC LIM) and turn on
math operations (CALC:STAT ON) before you set a limit value.
You can assign a lower limit, an upper limit (see CALCulate:LIMit:UPPer
command), or both. The lower limit must always be less than or equal to
the upper limit, even if you are using only one of the limits.
Limit crossing: If a reading is less than the specified lower limit, bit 11
("Lower Limit Failed") is set in the Questionable Data Register, which
results in an SRQ if enabled. You can use the
STATus:QUEStionable[:EVENt]? command to read the event register. See
STATus Subsystem Introduction for further information.
The instrument clears all limits after a Factory Reset (*RST command) or
an Instrument Preset (SYSTem:PRESet command), or when the math
function or measurement function is changed.