Hi,
You can use the A and B triggers to set up triggering on sequential events for example, where the A trigger acts as a qualifier. You can read more about their dual usage in page 134 of the
MSO 4 series user manual.
As for the SCPI commands you are looking for;
- Setting trigger source to channel 3 (example using edge trigger type):
TRIGger:{A|B}:EDGE:SOUrce CH3
- Setting trigger level to 50% can be done with;
TRIGger:{A|B|B:RESET} SETLevel
Furthermore, if you want to know what the trigger parameters are after setting it to 50%, you can also query using (example using trigger A):
TRIGger:A?
-Iris