Wiki source code of Trigger Howto

Version 10.1 by sndueste on 2019/09/17 14:29
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sendels 1.1 1
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sndueste 6.1 3 {{toc/}}
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sndueste 10.1 5 = Introduction (user panel)
6 =
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sndueste 6.1 8 The MTCA based triggers have a jitter in the few ps range, the delay can be shifted in 1 ns steps (over many ms), one can choose between 10 Hz triggers, frequencies locked to the pulses (e.g. 1MHz) and the actual bunch patterns. A detailed description can be found in [[x2Timer manual>>attach:x2Timer.pdf]].
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sndueste 6.1 10 in short: the triggers are for low impedance (~~50 OHM terminated ?? ), 5V triggers with an adjustable width. The main control panel for the x2 timer has the control options for the 3 front modules (connected with a RJ45 cable - connecting to a "trigger box" with 2 trigger exits (Lemo) each) and 8 Lemo exits at the back of the crate. in the BL-beamline case these triggers are connected to the BNC (patch panel) ports at the rack.
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sndueste 6.1 12 The main control can be done with a simplified user panel which can handle the timing in respect to the FEL pulses and not in respect to some (arbitrary) reference time ( Event)[[~[~[image:url:http://hasfweb.desy.de/pub/Setup/TriggerHowto/Trigger_scheme.gif~|~|alt="Trigger_scheme.gif" width="800"~]~]>>attach:Trigger_scheme.gif]]
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sndueste 10.1 17 = Different trigger events (starting points) =
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sndueste 6.1 19 one can configure each channel for an individual trigger event
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21 **FLASH1**
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sendels 2.1 23 (% class="wrapped" %)
sendels 1.1 24 |(((
25 trigger No
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27 function
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30 16
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32 the MCA trigger 3.11 ms before the Flash1 pulses (same as A6 but more stable)
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37 A6 event. still possible to use but less precise than 16
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42 A2 event as earliest ( 24 ms before the FEL)
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47 E0 event of the BL fast shutter ( 19 ms before the FEL)
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50 225
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52 E1 event of the PG fast shutter ( 19 ms before the FEL)
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55 21
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57 Trig16 + first bunch of FLASH1 - this trigger is shifted when FL1 starts later than "700"
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64 **FLASH2**
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sendels 2.1 66 (% class="wrapped" %)
sendels 1.1 67 |(((
68 trigger No
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70 function
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73 22
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75 Trig116 + first bunch of FLASH2 - this trigger is shifted when FL2 starts at a different start time
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78 181
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sndueste 6.1 80 shifts with the start time of FLASH2 as event 22 but comes 22 ms ! before the FEL
sendels 1.1 81 )))
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sndueste 5.1 83 from this trigger as starting point one can shift the timing in 9 ns steps first and finally in 0.9 ns steps for fine adjustment.
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sndueste 6.1 87 = Expert panels =
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sndueste 6.1 91 [[image:attach:image2019-9-17_13-10-56.png||height="250"]] [[image:attach:image2019-9-17_13-8-46.png||height="400"]]
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sndueste 7.1 93 With the **"Expert overview"** one gets the overview over all channels available on the timing card and can configure the card. This is useful to look what channels are using clock settings or burst mode settings that one wants to change ... and using the other tabs one can set parameters for clocks and bursts (see below)
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sndueste 7.1 97 For each trigger channel there is in addition an **"Expert panel"** to set the properties of THIS channel
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99 [[image:attach:image2019-9-17_13-14-52.png||height="250"]] [[image:attach:image2019-9-17_13-15-38.png||width="550"]]
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sndueste 10.1 107 = Set a constant frequency to a channel =
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109 =
sndueste 6.1 110 [[image:attach:image2019-9-17_13-18-9.png||height="250"]][[image:attach:image2019-9-17_13-18-37.png||height="149"]] =
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sndueste 7.1 114 The timer card provides the option to generate  frequencies that are synched to the FEL reprate on the ps level. One can set 3 Clocks by deviding the reference frequency of 54.2 MHz by n.** Please check (using the Expert overview ) before changing a frequency of it is used for some other channel !!**
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116 Since our main FEL frequency is 100.31 MHz the dividers are not straight forward:
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sndueste 10.1 118 [[image:attach:image2019-9-17_14-22-29.png||width="450" align="right"]]
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sndueste 7.1 122 (% class="wrapped" %)
sndueste 6.1 123 |=(((
124 Clock frequency
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sndueste 7.1 126 Divider to be set
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129 "1 MHz" (1000.31 kHz)
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sndueste 7.1 134 "500 kHz" (501.5 kHz)
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sndueste 7.1 136 107
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sndueste 7.1 139 "250 kHz" (250.8 kHz)
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sndueste 7.1 141 215
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sndueste 7.1 143 |(% colspan="1" %)(((
144 "200 kHz" (200.6 kHz)
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146 269
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148 |(% colspan="1" %)(((
149 "100 kHz" (100.3 kHz)
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151 539
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sndueste 7.1 162 Once a clock is configured with the right frequency one can choose in the "expert panel" of the according channel the "FPGA clock" in the "input source select"  chooser.
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sndueste 10.1 170 One has to set the delay to values less than the repetition rate ... (so for 1 MHz between 0 and 990 µs)  and the trigger width also less than the rep rate ...
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178 This results in a continuous train of pulses with the set trigger width :
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180 = Creating an (own) burst trigger =
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182 One can use now a SECOND trigger channel which is set to a regular 10 Hz trigger  and gate the clock output to create a burst with defined start point and length,
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sendels 1.1 198 * in order to generate a stable frequency one has to set the input source to FPGA clock (and use dividers to get the desired frequency)
sndueste 4.1 199 * to generate the burst patterns of the FEL one has to choose a trigger event (best 116 for FLASH 2 and 16 for FLASH1) and activate Destination 1 for FLASH1 and Destination 2 for FLASH2 . finally one has to assign the activated Bunch pattern mask to the trigger channel of choice . now the pattern can be shifted and the trigger width can be changed as with the 10 Hz triggers. **IMPORTANT: to move the bunchtrain to the desired starting point the DELAY in the expert panel (see below) has to be used. The Trigger in the user panel (see above) has to be set to 0 !!!**
sendels 3.1 200 [[~[~[image:url:http://hasfweb.desy.de/pub/Setup/TriggerHowto/mtcatrigger2k.png~|~|alt="mtcatrigger2k.png" width="607" height="458"~]~]>>attach:mtcatrigger2k.png]]
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sndueste 4.1 202 here an example defining the bunch pattern for FLASH1 to mask 1
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