Requirements%20of%20CMS%20on%20the%20BST

1
LHC Experiment Accelerator Data Exchange Working
Group
Requirements of CMS on the BST 
1. Trigger Fast Control 2. Detector Control
System 3. Requirements on BST
J. Varela LIP Lisbon / CERN
2
Trigger Fast Control
TTCmi
DAQ Event Managers
Global Trigger
LHC-BST GPS
aTTS
Central Control
Partition Control
Partition Control
Partition Control
L1A Control Front-end Emulators, Trigger
Rules Trigger Throttling System (sTTS and
aTTS) Calibration and Test Triggers Dedicated
runs, Special triggers during runs Synchronization
Control Timing signals, Resync procedures
Partitioning 8 independent partition groups, 8
independent triggers
Local Triggers
Local Control
Local Control
Local Control
BST
TTC
sTTS
TTC
sTTS
TTC
sTTS
FrontEnd
FrontEnd
FrontEnd
TTCrx
TTCrx
TTCrx
3
Trigger Control Components
BST link
To EVM
GLOBAL TRIGGER CRATE
To/from aTTS
TTCmi
Central Trigger Control
ClockOrbit
TTC
(x 32)
(x 32)
TTS
Local Triggers
Fast Merging Module
BST link
CPU int
F M M
TTCex
TTCci
F M M
LTC
TTS
...
...
FMM
TTC
SYNC TTS
TTS Link
Subdetector Master TTC Crate
TTC Link
From/To SUBDETECTOR FRONTEND CRATES
Local Trigger Controller
4
TTCci Module

• TTCci Functions
• Selecting Central or Local control
• Internal storage of B commands
• Timing of B commands
• Internal Trigger generation
• L1A and B-data transmission

Interface to TTC optical distribution Replaces
TTCvi
Development by Tony Rohlev (Wisconsin/CERN)
5
Trigger Interface to DAQ
Trigger Record to EVM (Included in Event
Record) Begin of event 64 bits //Trigg
type, Eventnr, BCnr, SourceID.. Trigger number
24 of 32 //Nr of all L1A hex 00NN NNNN
DAQ TriggType BCnr 20 bits of 32 // 4412
bits , hex00DT 0BBB Subdetector partitions
32 bits // 1 partition is connected, 0 not
connected Event Number 24 bits of 32 // hex
00NN NNNN Orbit number 32 bits Technical
trigger bits 32 bits Algo bits_0 32 bits
Physics trigger algorithm bits 0...31 Algo
bits_1 32 bits Physics trigger algorithm
bits 32...63 Algo bits_2 32 bits Physics
trigger algorithm bits 64...95 Algo bits_3 32
bits Physics trigger algorithm bits
96...127 Algo bits_4 32 bits reserved for
optional upgrade Algo bits_5 32 bits
reserved for optional upgrade GPS time_0 32
bits // bytes 0-3 GPS time_1 32 bits //
bytes 4-7 End of Event 64 bits //Event
length, CRC.. (as for DAQ)
6
Detector Control System
GPS Time allows to correlate Event Data
with Detector Control Data

• Detector subsystems
• HV/LV
• Fluids and environment
• Cooling
• Racks/Crates
• Temperatures
• Infrastructures
• Test systems (Laser, LED, alignment camera etc..)
• Detector safety (DSS)
• Temperature
• Gas
• Radiation
• Experiment supervision
• DCS Resources handling
• Alarm and loggings
• History data base
• External systems communication.

7
Interface to LHC BST
LHC Beam Synchronous Timing System (BST)
gt BST used to synchronize LHC beam
instrumentation gt Distribution of BST messages
(once per orbit) uses TTC gt BST message 32
bytes, of which 8 bytes for GPS Time
Usage in CMS GPS Time added to Event
Record BST/TTC link to Central Trigger Control
(1 link) BST/TTC link to Local Trigger
Controllers (10 links) GPS Time and LHC Data
added to DCS Data BST/TTC link to central VME
receiver (BOBR) (complementary to access to LHC
data via DIP)
8
BST Message Contents
time granularity of 1ms
Subject to change ?
time granularity of 1turn
9
BST Overview
BOBR
Clocks
Bunch Turn Clocks
Universal time Machine Events (?) Beam Parameter
s Real-time commands Hardware triggers
BST MESSAGE RECEIVER
TTCrx
Data Bytes
1
TTC Optical Network
BST MESSAGE ASSEMBLER
TTC Encoder Optical Transmit.
1
CTC
TTCrx
10
LTC
TTCrx
CMS specific BST items should be located in racks
S1 E 8-10 (LHC, BPTX, BPM)
Located in Central Trigger and TTC racks (S1 E
2-4)
10
Summary of Requirements to BST
Distribution of BST messages to the
experiment Final specification of BST message
content and format Specification of BST/TTC
message protocol and timing Update of GPS time
once per 10 orbits (or better) CMS specific BST
items should be located in racks LHC, BPTX or BPM
(S1 E 8-10)