...

• 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

Sequencing

...

Example

See https://github.com/slac-lcls/lcls2/blob/master/psdaq/psdaq/seq/seqprogram.py and https://github.com/slac-lcls/lcls2/blob/master/psdaq/psdaq/seq/burst.py for an example of how to generate complex patterns of event codes (the latter file is an argument given to the former).

In this example the XPM is configured to insert event codes 272-287 into the timing stream.  Four event codes are generated by each sequence engine within the XPM.  The XPM has 4 sequence engines allowing 16 event codes total.

A current example for doing this is done by executing:

(ps-4.5.24) bash-4.2$ python psdaq/psdaq/seq/seqprogram.py -h
usage: seqprogram.py [-h] [--engine ENGINE] seq pv

sequence pva programming

positional arguments:
  seq              sequence script
  pv               sequence engine pv; e.g. NEH:DAQ:XPM:0

optional arguments:
  -h, --help       show this help message and exit
  --engine ENGINE  sequence engine

(ps-4.5.24) bash-4.2$ python psdaq/psdaq/seq/seqprogram.py psdaq/psdaq/seq/33k_35k.py DAQ:NEH:XPM:6

The event codes generation by an XPM may be queried via a status PV.

(ps-4.5.24) bash-4.2$ pvget DAQ:NEH:XPM:6:SEQCODES

DAQ:NEH:XPM:6:SEQCODES 2023-01-19 10:35:20.971    

EventCode  Description  Rate

      272 "33kHz base" 33164
      273 "35kHz base" 35715
      274                  0
      275                  0
      276                  0
      277                  0
      278                  0
      279                  0
      280                  0
      281                  0
      282                  0
      283                  0
      284                  0
      285                  0
      286                  0
      287                  0

...