Keysight Technologies 34450A Programmer's Reference Manual page 304

2 SCPI Programming
Return Format
The query command returns the present trigger source: "IMM", "BUS", or "EXT".
Examples
The following command selects the bus (software) trigger source. Note that the *TRG command will not be
accepted unless the instrument is in the "wait-for-trigger" state (INIT command).
TRIG:SOUR BUS
INIT
*TRG
FETC?
The following query returns the trigger source currently selected.
TRIG:SOUR?
Typical Response: IMM
See Also
Triggering the Multimeter
*TRG
304 Keysight 34450A Programmer's Reference