...

It's a common question to ask what are the rates that the accelerator can generate.  The table below lists the rates that are natural for the accelerator.  These are the periodic rates that repeat exactly at the ~0.98 second period of the timing/MPS system.  Of course, we can generate other rates as well that aren't exactly periodic by doing the sort of thing you described - dropping shots or irregular sequences.  This has been useful for the OPCPA laser development in deciding the exact frequencies they will support.

If a base accelerator rate is chosen (e.g. 33kHz) then other rates having the same prime factors as the accelerator rate are allowed, according to this table:

(python3_env) [weaver@lcls-dev3 lcls2-timing-patterns]$ python lcls/fixed_rate_table.py

Matt provides this example of how you can determine if various trigger rates overlap: 16kHz (16581 in the table) has factors (2,2,2,7).  102Hz has factors (2,2,5,5,7,13).  It's missing one factor of 2, so it only overlaps 1/2 of the time.  51Hz has (2,2,2,5,5,7,13), so it contains all the factors from 16kHz and thus overlaps 100%.

If a base accelerator rate is chosen (e.g. 33kHz) then other rates having the same prime factors as the accelerator rate are allowed, according to this table:

(python3_env) [weaver@lcls-dev3 lcls2-timing-patterns]$ python lcls/fixed_rate_table.py

 rate, Hz  | factor | factors
 928571 rate, Hz  | factor | factors
 928571          1   1
 464285          2   (2,)
 232142          4   (2, 2)
 185714          5   (5,)
 132653          7   (7,)
 116071          8   (2, 2, 2)
  92857         10   (2, 5)
  71428         13 1   (13,)
  66326 1
 464285         14 2   (2, 7)
  58035 232142         16 4   (2, 2, 2, 2)
  185714 46428         20 5   (2, 2, 5)
  37142 5,)
 132653         25 7   (57, 5)
  116071 35714         26 8   (2, 132, 2)
  3316392857         2810   (2, 2, 75)
  2653071428         3513   (513, 7)
  2321466326         4014   (2, 2, 2, 57)
  1857158035         5016   (2, 52, 2, 52)
  1785746428         5220   (2, 2, 135)
  1658137142         5625   (25, 2, 2, 75)
  1428535714         6526   (52, 13)
  1326533163         7028   (2, 52, 7)
  1160726530         8035   (25, 2, 2, 2, 57)
  1020423214         9140   (72, 2, 2, 135)
   928518571          10050   (2, 2, 5, 5)
  17857  8928         10452   (2, 2, 2, 13)
   829016581          11256   (2, 2, 2, 2, 77)
  14285  7428         12565   (5, 5, 513)
  13265  7142         13070   (2, 5, 137)
  11607  6632         14080   (2, 2, 52, 2, 75)
  10204  5306         17591   (57, 5, 713)
   5102 9285        182 100   (2, 72, 5, 135)
   4642 8928        200 104   (2, 2, 2, 5, 513)
   4464 8290        208 112   (2, 2, 2, 2, 137)
   3714 7428        250 125   (2, 5, 5, 5)
   3571 7142        260 130   (2, 2, 5, 13)
   3316 6632        280 140   (2, 2, 2, 5, 7)
   2857 5306        325 175   (5, 5, 137)
   2653 5102        350 182   (2, 57, 5, 713)
   2551 4642        364 200   (2, 2, 72, 5, 135)
   2321 4464        400 208   (2, 2, 2, 2, 5, 513)
   2040 3714        455 250   (2, 5, 75, 135)
   1857 3571        500 260   (2, 2, 5, 5, 513)
   1785 3316        520 280   (2, 2, 2, 5, 137)
   1658 2857        560 325   (2, 2, 25, 2, 5, 713)
   1485 2653        625 350   (52, 5, 5, 57)
   1428 2551        650 364   (2, 52, 57, 13)
   1326 2321        700 400   (2, 2, 2, 52, 5, 75)
   1275 2040        728 455   (2, 25, 2, 7, 13)
   1061 1857        875 500   (52, 2, 5, 5, 75)
   1020 1785        910 520   (2, 52, 2, 75, 13)
    928 1658       1000 560   (2, 2, 2, 52, 5, 57)
    1485 892       1040 625   (25, 25, 25, 2, 5, 13)
    742 1428       1250 650   (2, 5, 5, 5, 513)
    1326 714       1300 700   (2, 2, 5, 5, 137)
    663 1275       1400 728   (2, 2, 2, 57, 5, 713)
    1061 637       1456 875   (25, 25, 25, 2, 7, 13)
    571 1020       1625 910   (52, 5, 57, 13)
    530928       17501000   (2, 52, 2, 5, 5, 75)
    510892       18201040   (2, 2, 52, 2, 75, 13)
    464742       20001250   (2, 25, 2, 2, 5, 5, 5)
    408714       22751300   (52, 2, 5, 75, 13)
    371663       25001400   (2, 2, 52, 5, 5, 57)
    357637       26001456   (2, 2, 2, 52, 57, 13)
    331571       28001625   (2, 2, 2, 25, 5, 5, 713)
    285530       32501750   (2, 5, 5, 5, 137)
    265510       35001820   (2, 2, 5, 57, 5, 713)
    255464       36402000   (2, 2, 2, 2, 5, 75, 135)
    212408       43752275   (5, 5, 57, 5, 713)
    204371       45502500   (2, 2, 5, 5, 75, 135)
    185357       50002600   (2, 2, 2, 5, 5, 5, 513)
    178331       52002800   (2, 2, 2, 2, 5, 5, 137)
    142285       65003250   (2, 2, 5, 5, 5, 13)
    132265       70003500   (2, 2, 2, 5, 5, 5, 7)
    127255       72803640   (2, 2, 2, 2, 5, 7, 13)
    114212       81254375   (5, 5, 5, 5, 137)
    106204       87504550   (2, 5, 5, 57, 5, 713)
    102185       91005000   (2, 2, 2, 5, 5, 75, 135)
    178  92       100005200   (2, 2, 2, 2, 5, 5, 5, 513)
     81142        113756500   (52, 2, 5, 5, 75, 13)
     71132        130007000   (2, 2, 2, 5, 5, 5, 137)
    127  66       140007280   (2, 2, 2, 2, 5, 57, 5, 713)
    114  57       162508125   (2, 5, 5, 5, 5, 13)
     53106        175008750   (2, 2, 5, 5, 5, 5, 7)
     51102        182009100   (2, 2, 2, 5, 5, 7, 13)
     40 92      22750 10000   (2, 2, 2, 52, 5, 5, 75, 135)
     35 81      26000 11375   (25, 25, 25, 2, 5, 5, 57, 13)
     28 71      32500 13000   (2, 2, 52, 5, 5, 5, 13)
     26 66      35000 14000   (2, 2, 2, 52, 5, 5, 5, 7)
     25 57      36400 16250   (2, 25, 25, 2, 5, 5, 7, 13)
     20 53      45500 17500   (2, 2, 5, 5, 5, 75, 137)
     16 51      56875 18200   (52, 2, 52, 5, 5, 7, 13)
     14 40      65000 22750   (2, 2, 2, 5, 5, 5, 57, 13)
     13 35      70000 26000   (2, 2, 2, 2, 5, 5, 5, 5, 713)
     10 28      91000 32500   (2, 2, 25, 5, 5, 5, 7, 13)
      8 26     113750 35000   (2, 2, 2, 5, 5, 5, 5, 7, 13)
      7 25     130000 36400   (2, 2, 2, 2, 5, 5, 57, 5, 13)
      5 20     182000 45500   (2, 2, 2, 2, 5, 5, 5, 7, 13)
      16 4     227500 56875   (2, 2, 5, 5, 5, 5, 7, 13)
      14 2     455000 65000   (2, 2, 2, 5, 5, 5, 5, 7, 13)
      13 1     910000 70000   (2, 2, 2, 2, 5, 5, 5, 5, 7, 13)

Event Codes

• 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)

Trigger Types

...

• sequences
• ac-line rate (1,5,10,30Hz...)
• fixed-rate patterns (1, 10, 100, 1000, 10000, 71kHz, 929kHz)

...

)
     10      91000   (2, 2, 2, 5, 5, 5, 7, 13)
      8     113750   (2, 5, 5, 5, 5, 7, 13)
      7     130000   (2, 2, 2, 2, 5, 5, 5, 5, 13)
      5     182000   (2, 2, 2, 2, 5, 5, 5, 7, 13)
      4     227500   (2, 2, 5, 5, 5, 5, 7, 13)
      2     455000   (2, 2, 2, 5, 5, 5, 5, 7, 13)
      1     910000   (2, 2, 2, 2, 5, 5, 5, 5, 7, 13)

Triggering Devices With Beam

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).  See table below where DumpSXR destination corresponds to destination bit 4.   It is also important to set the "select" field to "Inclusive" (see below for daq configuration object GUI).

Another important method (used especially for low rate 1,10,100Hz triggers that are in-synch with the beam) is to use an event-code generated by ACR (see Control Sequence Bit for currently supported event codes).  cpo thinks event codes like "SC_SXR BSA" (e.g. 100Hz is eventcode 30) on that page would be commonly used by the hutches. NOTE: We have seen empirically that these event codes do not include a destination setting, so it is necessary to also select destination 4 with the "select" field set to "inclusive" with them.  Matt writes: "Event code 30 will follow the offset used by SXR, but it isn't aware of MPS mitigating the beam rate.  We use the destination 4 filter to also pickup when MPS has inhibited the beam."

Image Added

Some details:

• there are 288 bits of "event codes" available
  • some have well-defined meanings, like the low-rate ones described above (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, in particular DumpBSY for "dropped" or "background" shots
• some devices reference to "sequencer engineer number" and "sequence bit number" instead of "eventcode".  The formula to convert between the two: eventcode=(sequenceEngine#<<16 | sequencerBit#).

Trigger Destinations and Types

Timing receivers share a common logic module for generating triggers.  They consist of the logical AND of two components, a rate component and a beam destination component.

• Rate component.
  • sequences / event code
  • ac-line rate (1,5,10,30Hz...) + timeslot mask
  • fixed-rate patterns (1H, 10H, 100H, 1kH, 10kH, 71kH, 1MH)
• Beam destination component
  • "Dont Care" : beam or no beam, we don't care
  • "Inclusive" : specify a set/mask of destinations to which the beam must be destined; see the table below
  • "Exclusive" : specify a set/mask of destinations to which the beam must not be destined; see the table below.

Note: destination "DumpBSY" corresponds to dropped-shots.

Need to coordinate hutch sequence-pattern scripts with accelerator sequence-pattern (patterns repeat on 1H marker).

Sequencing Example

See https://github.com/slac-lcls/lcls2/blob/master/psdaq/psdaq/seq/rixexample.sh (high level example for bursts and period patterns) and Integrating Detectors in RIX.  See also Matt's documentation.

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.event codes total.

A current example for doing this is done by executing:

(first use Matt's high-level utility to generate two event codes that run at 10Hz and 100Hz (periods 91000 and 9100 respectively)

(ps-4.5.26) drp-srcf-mon001:psana$ periodicgenerator -p 91000 9100 -s 0 0 -d '10Hz' '100Hz' >& 10hz_100hz.py

(now program sequence engine 0 and start it using the python code generated above. since we're programming engine 0, the first two event codes will be 272,273 according to the above table)

(this command must be executed on a node that can access the XPM PV's, e.g. drp-srcf-*)

(ps-4.5.26) drp-srcf-mon001:psana$ seqprogram --seq 04:10hz_100hz.py --pv DAQ:NEH:XPM:3 --start
** engine 0 fname 10hz_100hz.py **
descset  None
seqcodes {0: '10Hz', 1: '100Hz'}
Remove -1
idx 2
Removing seq 2
[10, 1, 5, 3, 0, 0, 0, 0, 2, 0, 6, 2048, 0, 0, 0, 3, 2, 1, 3, 3, 0, 0, 2, 0, 6, 908, 0, 0, 0, 1, 5, 2, 0, 0, 0, 0, 3, 2, 1, 0, 8, 0, 0, 2, 0, 6, 2048, 0, 0, 0, 3, 2, 6, 3, 3, 0, 0, 2, 0, 6, 908, 0, 0, 0, 1, 2, 0, 0, 0, 0, 0]
Confirmed ninstr 10
Sequence  found at index 2
desc ['10Hz', '100Hz', '', '', '', '', '', '', '', '', '', '', 'burst', '', '', '']
seqcodes_pv epics:nt/NTTable:1.0 
    string[] labels [EventCode, Description, Rate, Enabled]
    structure value
        int[] EventCode [272,273,274,275,276,277,278,279,280,281,282,283,284,285,286,287]
        string[] Description [10Hz, 100Hz, , , , , , , , , , , burst, , , ]
        int[] Rate [11,102,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
        byte[] Enabled [1,1,1,1,0,0,0,0,0,0,0,0,1,1,1,1]
    string descriptor 
    alarm_t alarm
        int severity 0
        int status 0
        string message 
    time_t timeStamp
        long secondsPastEpoch 1683163040
        int nanoseconds 339389440
        int userTag 0

(now query the xpm to see what is running in the 4 sequence engines, each having 4 event codes)

(ps-4.5.26) drp-srcf-mon001:psana$ pvget DAQ:NEH:XPM:3:SEQCODES
DAQ:NEH:XPM:3:SEQCODES 2023-05-03 18:17:31.339    
EventCode Description Rate Enabled
      272        10Hz   10       1
      273       100Hz  102       1
      274                0       1
      275                0       1
      276                0       0
      277                0       0
      278                0       0
      279                0       0
      280                0       0
      281                0       0
      282                0       0
      283                0       0
      284       burst    0       1
      285                0       1
      286                0       1
      287                0       1
(ps-4.5.26) drp-srcf-mon001:psana$ 

Note: the periodicgenerator "repeat" argument specifies the number of repeats of the slowest event-code.

There is a similar "traingenerator" script which you can read about in Matt's documentation.

Visualizing Sequences

NOTE: this sequence browser currently only exists in the "allow_order" branch of git, but presumably will be migrated to the main branch.

This can be done on rhel6-64.stanford.edu (or other machine with access to afs) to visualize patterns:

git clone https://github.com/slaclab/lcls2-timing-patterns.git
cd lcls2-timing-patterns
make
source env.sh
python tools/seqbrowser.py --seq 0:codes.py 3:beam.py --time 2.0

codes.py and beam.py were created with these scripts in the psdaq package:

traingenerator -s 14000 -b 28 -n 32001 -r 2 -d "burst" -t 910000 > beam.py
periodicgenerator -p 91 91000 -s 0 0 -d '10kHz' '10Hz' --repeat 3 --notify > codes.py

The seqbrowser.py command brings up this window which shows the two periodic event codes (programmed into the first simulated sequence engine) and the one "beam burst" event code (programmed into the fourth simulated sequence engine):

Image Removed

Sequence Start/Stop

Some technical details from a discussion on March 23, 2023

you can read about in Matt's documentation.

Visualizing Sequences

This can be done with the same environment used to generate the sequences above.

cd ~tmoopr/daq
source setup_env.sh
seqplot --seq 0:codes.py 3:beam.py --time 2.0

codes.py and beam.py were created with these scripts in the psdaq package:

traingenerator -s 14000 -b 28 -n 32001 -r 2 -d "burst" -t 910000 > beam.py
periodicgenerator -p 91 91000 -s 0 0 -d '10kHz' '10Hz' --repeat 3 --notify > codes.py

The seqplot command brings up this window which shows the two periodic event codes (programmed into the first simulated sequence engine) and the one "beam burst" event code (programmed into the fourth simulated sequence engine):

Image Added

Sequence Start/Stop

Some technical details from a discussion on March 23, 2023

Since a sequence in a lower-level XPM can "overwrite" sequence eventcodes from a higher-level XPM it is important to be able to stop lower-level sequences.  Matt says one does this by setting DAQ:NEH:XPM:2:SEQENG:3:ENABLE (for example) to 0.  The current example where we have to careful of this is for XPM0 which the laser group uses for eventcodes 272,273,274.

Matt has added a Groups/EventCodes tab to the xpmpva tool.  It shows you the effect of overwriting and which xpm is the current source of eventcodes.

currently the XPM starts sequences on 1Hz boundary (e.g. every 910000 buckets). currently start sequences on 1Hz boundary.   this slows down the daq scan steps, so so support for a second mode is being considered:

(1) current seq mode (only program time-in-seconds or numL1Accepts)
    -seconds or numL1Accepts)
    have to coordinate the start of an accelerator burst with the daq sequence
    - are there two sequences?  one for accelerator and one for daq?
      not clear how much control the accelerator will want (e.g. burst
      all the time for stability, but silke says can damage samples)
    - each step we start one sequence:
      o may also include control of accelerator, but if not
      o have to coordinate the start of an accelerator burst with the daq sequence
    - are there two sequences?  one for accelerator and one for daq?
      not clear how much control the accelerator will want (e.g. burst
      all the time for stability, but silke says can damage samples)
    - each step we start one sequence:
      o may also include control of accelerator, but if not
      o have to coordinate the start of the daq seq with accelerator seq
        o acc seq synced to 1Hz marker (everything repeats at 1Hz on
      accelerator side)
    o trickier to sync to rates faster than 1Hz
(2) future-firmware seq mode
    - make the daq enable/disable on a user-defined event code
      o would be faster on the enable since don't have to wait for 1Hz
        marker.  still have to understand the periodicity of the accelerator
    so the user-defined event codes get sent down at the right time
    but it does mean we don't need the slow 1Hz marker.  some things like
    laser electronic delay scanning may be faster than 1Hz so could benefit
    from not using the 1Hz marker.

andor integrates over 10 shots
6 andor images in a step

mode (1):
- program 6 andor-readout-group "L1Accepts".  might be set to the parent
  group now in control.py

the readout group that is counted for the sequence is currently managed
by these lines in control.py.  Currently defaults to the "platform" readout
group which is the primary readout group: need to make this more flexible
so we can change it to the integrating detector readout group:

the daq seq with accelerator seq
        o acc seq synced to 1Hz marker (everything repeats at 1Hz on
      accelerator side)
    o trickier to sync to rates faster than 1Hz
(2) future-firmware seq mode
    - make the daq enable/disable on a user-defined event code
      o would be faster on the enable since don't have to wait for 1Hz
        marker.  still have to understand the periodicity of the accelerator
    so the user-defined event codes get sent down at the right time
    but it does mean we don't need the slow 1Hz marker.  some things like
    laser electronic delay scanning may be faster than 1Hz so could benefit
    from not using the 1Hz marker.

andor integrates over 10 shots
6 andor images in a step

mode (1):
- program 6 andor-readout-group "L1Accepts".  might be set to the parent
  group now in control.py

the readout group that is counted for the sequence is currently managed
by these lines in control.py.  Currently defaults to the "platform" readout
group which is the primary readout group: need to make this more flexible
so we can change it to the integrating detector readout group:

self.pv_xpm_part_base = pv_base + ':XPM:%d:PART:%d' % (xpm_master, platform)
self.pva.pv_put(self.pva.pvStepEnd, self.readoutCumulative)

Generating a Low Rate Sequence

From Matt.

periodicgenerator --period 1820000 --start_bucket 91000 --description 'Example 0.5Hz sequence' > 0.5Hseq.py
(ps-4.6.1) bash-4.2$ seqplot --seq 0:0.5Hseq.py --time 4.0
eng 0 fn 0.5Hseq.py
0: FixedRateSync(929kHz) # occ(2048)
1: Branch to line 0 until ctr3=43
2: FixedRateSync(929kHz) # occ(888)
3: ControlRequest word 0x1 [0]
4: FixedRateSync(929kHz) # occ(2048)
5: Branch to line 4 until ctr3=843
6: FixedRateSync(929kHz) # occ(488)
7: Branch unconditional to line 0
start, stop: 0,3640000
engine exited request 0  instr 1  returnaddr None  frame 3642047  ccnt [0, 0, 0, 0]

Should show eventcode 272 at bucket 91,000 and every 1,820,000 (2 seconds) after that.

Image Addedself.pv_xpm_part_base = pv_base + ':XPM:%d:PART:%d' % (xpm_master, platform)
self.pva.pv_put(self.pva.pvStepEnd, self.readoutCumulative)