EVR Data (Timing System)

This script lives in /reg/g/psdm/tutorials/examplePython/evr.py.  EVR data is often used to determine what happened on an event by looking at "event codes".  Experiments often use these event codes to indicate whether a pump laser was on/off for a particular shot, or whether beam was present on that shot ("dropped shots").  Experiments sometimes set up complex "event sequences" to create different behavior on different shots (via different event-codes generated by the LCLS timing system).

from psana import *
ds = DataSource('exp=xpptut15:run=54:smd')
for nevent,evt in enumerate(ds.events()):
    evr = evt.get(EvrData.DataV4, Source('DetInfo(NoDetector.0:Evr.0)'))
    if evr is None: continue
    for fifoEvent in evr.fifoEvents():
        print fifoEvent.eventCode(),
    print
    if nevent==3: break