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• The accelerator provides exactly 910,000 buckets in exactly 0.98 seconds
• The accelerator patterns repeat on this 0.98s interval
• The ratio of these two numbers is what gives rise to the 929kHz (~1MHz) machine rate.  Also is 13/14MHz
• timing arrives 100us prior to beam
• The 71428Hz rate is special: common between LCLS1 and LCLS2

Presentation

A presentation from Matt:

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• 288 bits of "event codes":
  • some have well-defined meanings (in progress)
  • 16 highest bits are hutch specific for sequences (272-287)
  • DAQ readout groups are "extra bits" included at end of timing frame
• timing frames have "destinations": e.g. bykiks, and bykikh both go to "bsy" dump
• unlike LCLS1 we will not be using event-codes to understand when bykiks has fired: use destinations instead
• To trigger on "every shot" with beam (the equivalent of LCLS1's eventcode 140) use "Mode=FixedRate:1MHz, Destination=Include:DumpSXR" (without the "destination" field I believe you will just get a pure 1MHz trigger)

Rates

• timing arrives 100us prior to beam
• accelerator max rate is 13/14MHz=929kHz
• The 71428Hz rate is special: common between LCLS1 and LCLS2
• 928kHz is max rate, but accelerator pattern repeats every 910k buckets

Trigger Types

• timing trigger types:
  • sequences
  • ac-line rate (1,5,10,30Hz...)
  • fixed-rate patterns (1, 10, 100, 1000, 10000, 71kHz, 929kHz)
• need to coordinate hutch sequence-pattern scripts with accelerator sequence-pattern

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