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QPS Data Transmission after LS1

R. Denz, TE-MPE-EP TIMBER

PMWinCC OA

Tsunami warning: https://cds.cern.ch/record/1424362 (Feb. 2012)

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QPS - protection of superconducting elements in the LHC

Circuit type Quantity

Main bends and quads 24

Inner triplets 8

Insertion region magnets 94

Corrector circuits 600 A 418

Total 544

Protection system type Quantity

Quench detection systems 13440

Quench heater discharge power supplies 6076

Energy extraction systems 13 kA 32

Energy extraction systems 600 A 202

Data acquisition systems 2574 (~2300 exposed to ionizing radiation)

Software supervision channels 93584

System interlocks (hardwired) 13560

• Dependability of the system is critical for LHC performance.• Due to the mere size of the system, reliability, availability and

maintainability are a major challenge.• QPS supervision is used for the operation of the system and for

the diagnostics of the superconducting elements.• During LHC operation access to the QPS systems is very

restricted and practically impossible for the superconducting elements ( warm-up!).

• In consequence it is vital to have a maximum of information available for remote diagnostics.

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QPS supervision - basic architecture

nQPS

IPD, IPQ, IT600 A Leads main circuits EE

QPS supervision provides data for:• Operator screens (WinCC OA) and expert consoles• Software interlocks (QPS_OK signal)• LHC logging database• Post mortem servers, viewers and automatic analysis• Warning generation (SMS, email) for pre-defined faults states

(e.g. loss of a quench heater power supply)

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QPS DAQ systems

Fieldbus (WorldFip™) controlled data acquisition system

– Synchronized to accelerator time (∆t = 1 ms)

– Up to 8 analog input channels and up to 80 digital I/O channels

– Interfaces to associated equipment (SPI or I2C)

• Up to 16 active clients

2574 devices in LHC (~2300 exposed to ionizing radiation)

– Required radiation tolerance restricts functionality of field devices e.g. for data buffering and filtering

The present soon obsolete and not fully radiation tolerant field-bus coupler of the MicroFip™ type will be superseded by the CERN made NanoFip

– New circuit boards, firmware, supervision software …

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QPS raw data rates (the view from the bottom …)

Fieldbus of the WorldFIP™ standard (1 Mbit/s)

• WorldFIP™ macro-cycle length tmacro = 100 ms (pre LS1 200 ms)

• Clients are based on the MicroFIP™ ASIC

• Consumed variables TIME (global) and COMMAND, 8 Bytes each

• Produced variables DATA0, 1, 2, 3 (24 Bytes each)

• About 90% of the QPS fieldbus couplers are exposed to ionizing radiation

• Limited functionality with respect to data buffering and filtering

Raw data rates (not compressed, containing all available information)

post LS1/ pre LS1 = QPS2014/QPS2008 = 2 (≠ Moore’s law)

MB/s GB/h GB/day TB/week TB/year

Nominal 1.1 4.0 96.6 0.7 35.3

Maximum 2.5 8.9 213.5 1.5 77.9

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QPS data types

Booleans (flags) and states

• On change recording acceptable if signal refreshment can be traced (is true ...)

Slow analog values (0.1 Hz)

• Newly created for post LS1 operation

• Quench heater discharge power supply charging voltage (fast recording only during PM required)

• HTS current lead protection systems

• Bus-bar splice protection systems

• On change recording or filtering not permitted

“Fast” analog values (10 Hz)

• Magnet protection systems

• Systems treat signals significantly faster but transmit only during PM at full speed (some kHz)

• On change recording of filtering not permitted

• The major change compared to the pre LS1 situation is the suppression of the on change data recording of analog values using dead bands.

• Many complaints by QPS operators and users.• Significant part of recorded analog data actually has been

rendered useless by on change recording.• Post LS1 QPS operation will introduce automatic consistency

checks depending on properly recorded data.• Substantial effort to acquire data in the LHC environment not to

be spoiled easily.

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Conclusion

QPS supervision is an essential part of an important machine protection system

• Proper functioning cannot guaranteed without adequate data acquisition

• On change recording (or any kind of filtering) of analog data is not acceptable

• Data transmission rates might be slightly lowered in case of major problems

QPS upgrades introduced during LS1 focus on:

• Reduction of system down time, improved reliability and system maintainability

• Remote maintenance options

• Configuration database

• Improved radiation tolerance

• Enhanced supervision capabilities e.g. for quench heater circuits

• Automatic tools for system integrity checks

Limitation by the high level control systems in handling the QPS data flow needs to be understood

• Technology, manpower, hardware where is the real bottleneck?