caen power supplies - ucsbhep.ucsb.edu/si_workshop2006/talks/04_060512_cdf...crate naming...

CAEN power suppliesThe neverending story

Jennifer PursleyJohns Hopkins University

Silicon Workshop II, May 10-12, 2006University of California, Santa Barbara

J. Pursley - Silicon Workshop II 2

System overview:

Diagram courtesyof J. R. Mumford


Infrastructure: the SY527Universal Multichannel Power Supply system

! CAEN mainframe, has 10 board slots! NOT custom-made, also used for plug power supplies! Communicates via serial connection (RS232 port or

CAENET coaxial cable)! Control power supplies

(settings and on/off) from front panel

! NOT radiation hard, but located in the collision hall!

! These are what you hockerize (reboot the crate CPU)


Collision Hall Map: 16 crates! Mounted on CH

walls, with fib racks

! 4 crates in each corner, numbered clockwise (sort of…)

! Roughly, 2 PS crates = 1 fib

! Even number fib is SVX, odd is ISL/L00Diagram courtesy

of M. Stanitzki


Crate Naming Conventions

NW Bot BotSVX NW Bot 4Crate 8NW Bot TopSVX NW Bot 3Crate 7SW Bot BotSVX SW Bot 4Crate 6SW Bot TopSVX SW Bot 3Crate 5SW Top BotSVX SW Top 2Crate 4SW Top TopSVX SW Top 1Crate 3NW Top BotSVX NW Top 2Crate 2NW Top TopSVX NW Top 1Crate 1

PS InterlocksReset PanelCrate

West Side


Crate Naming Conventions

NE Bot BotSVX NE Bot 4Crate 16NE Bot TopSVX NE Bot 3Crate 15SE Bot BotSVX SE Bot 4Crate 14SE Bot TopSVX SE Bot 3Crate 13SE Top BotSVX SE Top 2Crate 12SE Top TopSVX SE Top 1Crate 11NE Top BotSVX NE Top 2Crate 10NE Top TopSVX NE Top 1Crate 9

PS InterlocksReset PanelCrate

East Side


The Workhorse: SVX Modules (A509)! Occupies 1 slot in SY527! 1 board powers 1 wedge

" 5 Bias channels" 5 Low voltage (AVDD & DVDD)" 2 portcard (2V & 5V DOIMs)" Total: 18 channels

! 73 supplies in CH (72 for SVX wedges, 1 for a L00 wedge)

! VMax = 250V, IMax = 5 mA! Cable pinouts designed for SVX

6014060170170VMax(V)

43210Layer


Next up: ISL Modules (A510)! Occupies 2 slots in SY527! 1 board powers 1 wedge

" 10 Bias channels" 5 Low voltage (AVDD & DVDD)" 2 portcard (2V & 5V DOIMs)" Total: 23 channels

! 30 supplies in CH! VMax = 250V, IMax = 5 mA! Bias Adapter, double LV cables

140140140140140VMaxCNTL

601406014060VMaxFWD

40,4130,3120,2110,1100,01Layer


Finally: L00 Modules (A509H)! Occupies 2 slots in SY527! 1 board powers 1 wedge

" 4 + 1 Bias channels" 4 Low voltage (AVDD & DVDD)" 2 portcard (2V & 5V DOIMs)" Total: 15 channels

! 11 supplies in CH! VMax = 500V, IMax = 36/23 mA! Sense, LV, and Bias adapers!! Extra feature: crowbar on bias line

160

3a,3b

909090VMax (V)

210Layer


L00 Crowbars

! Protect Si from PS failure! 2 mA fuse on each bias line! Now frequently blown in beam

incidents (eg kicker prefires or nasty quenches)! Blown fuse = no bias on sensor! Most L00 sensors draw measurable current now; check

for blown crowbars by biasing L00, look for 0 current

Automatic crowbar tester!

No light = blown fuse


Junction Cards! Same junction card used for SVX, ISL, and L00

" Extra LV and Bias connectors to accommodate ISL

! Cables in CH run from PS racks down into the bore" And across the COT face…

! This is the closest we can get to the silicon!

Diagram courtesyof J. R. Mumford


Common Failure Modes – SY527! Crate CPU gets in a funny state

" Some symptoms:! “Crate xx lost communication” (or you see anything turn

blue in IMON)! All supplies in one crate spontaneously turn off ! Garbled readback of voltage/current of a ladder (could

lead to trigger inhibit)

" Solution: hockerize!! Fan failures: frequent in plug crates, but

none of ours (yet…)! 1 damaged backplane (not fun!)! Remember: must turn crate off for ~10 mins

before removing power supplies, or could blow a PS fuse


Common Failure Modes – PS! Overcurrent trips

" Maybe the current is going high – try raising limit, watch plots" Also a common PS failure, usually fixable at FCC

! Overvoltage/Undercurrent trips" Approx. the same thing – if the voltage is set above the limit,

the supply clamps it down before tripping" Usually a PS failure

! Undervoltage trips" Supply can’t get to the set voltage" Common PS failure (esp. of ISL supplies), NOT fixable at FCC

! Software protection trips" Voltage/current doesn’t trip the hardware" Software limits stricter than hardware, but requires the value

stay above the limit for several mins before tripping" Usually denotes a readback problem, check values in IMON


Less Common Failure Modes! Transistor regulating the Bias voltage blows

" Symptoms: ladder voltage ramps up to VMax (250V or 500V) and doesn’t trip

" Can’t be turned off, have to cut power to the whole crate" This is the failure mode crowbars were introduced to prevent!

! Large current offsets! Erratic or oscillatory voltages/currents (seen on DVDD

and Bias)! Crate doesn’t recognize power supply

" Not fully connected to backplane, X28HC256 prom is garbled…" None of the other supplies in the crate will work if there’s one

in there the crate can’t recognize!

! Supply won’t work in one particular slot/crate, but is fine in another

! Usually require expert diagnosis!


Summary! Love ‘em or hate ‘em, CAENs are here to stay! Increasing frequency of failures may be due

to radiation exposure or aging" 9 PS swaps in 2005; 4 in first 3 months of 2006

! Do our best to:" Work w/ FCC to minimize downtime from common

failure modes (eg hockerization)" Hassle CAEN to make more spare crates and PS

(and to fix the broken ones faster!)" Get creative (such as, put a PS with failure on one

ladder in for a wedge where that ladder is out of the HWDB for other reasons!)

Backup Slides


Loadbox testing! Must test a new

PS before hooking it up to the detector

! Do this by cabling it to a junction card with a loadboxattached

! Loadbox uses constant and variable resistances to mimic a silicon wedge

caen power supplies - ucsbhep.ucsb.edu/si_workshop2006/talks/04_060512_cdf...crate naming...

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