the babar ifr low voltage system

1Marcello Piccolo Napoli Dec., 1997

The Babar IFR Low Voltage The Babar IFR Low Voltage SystemSystem

Naples, 12/15/1997

Electronic review


RequirementsRequirements

The FEC’s for the IFR include 3200 boards to do discrimination, pulse shaping and address encoding.

The FEC’s are located as close as possible to the pickup electrodes not to spoil with long cables the good time resolution of the RPC’s

FEC’s come in two flavors, as induction electrodes are on both sides of the RPC’s. Power consumption is different by 20% :

positive input FEC’s use more power than negative.

Two voltages are needed : +7 and -5.2 V Typical consumption are: +.31/-.12 neg.. Fec’s

+.37/-.16 pos. Fec’s Total power drawn: W (+7) , 2.5 KW(-5.2)

Corresponding currents : 1100 A (+7) , 450 A (-5.2)


Design PhilosophyDesign Philosophy

Given the amount of current to be supplied, locate power modules relatively close to utilization.

Use a relatively high number of power modules so that (unlikely) failures would bring down a limited part of the IFR.

Select a very reliable product (MTBF >40,000 h)

Use a connection scheme in which each board is independently attached to L.V.: most of the barrel boards in fact cannot be reached without opening BaBar …. and this is not even enough.


Power supply selectionPower supply selection

The devices we have selected are produced (almost custom) by Power Control System: Models chosen come in two types: 400W or

100W (output power). The MTBF quoted by the manufacturer is 80,000 h

and 100,000 h respectively. At full power = 75% (see Tech data sheet)

Other features include Forced ventilation for the 400 W model

95 oC shut-off

TTL/CMOS ramp down/up capability

Primary current limit @ 30 A for the 400 W model

Line regulation better than 1%

Load regulation better than 1% .

Calibrated shunts to measure output currents.


S-100-P Data Sheet S-100-P Data Sheet


S400-7 data sheet S400-7 data sheet


Power clustersPower clusters

The maximum number of boards to feed is : 1536 barrel 864 backward end cap 924 forward end cap

The spatial distribution of the boards forces the use of power cluster for each subsystem.

We have planned 2 power clusters for the barrel on each (East and West) platform, and one power cluster on each half endcap. The barrel power clusters consist of two 6U crates

(Barrel Supply Power Modules)which contain 3 7V/400W modules and one -5.2V/400W module.

The end-caps power clusters consist of ;

1 6U crate containing two 7V/400W modules and three -5.2V/100 W modules (HPSM) and 1 3U crate containing 1 7V/400W module and 1 -5.2/100W module.

The total power capability installed is 9.6 KW @+7V and 3.2 KW @-5.2. The power margin is about 20%.

Power dissipation of the cluster: 800 W barrel 400W end-caps.


The 6U barrel crateThe 6U barrel crate


The End-cap 6U crateThe End-cap 6U crate


Boards power distribution Boards power distribution

It is highly desirable to have individual (dis)connect of the boards, even if each of them is fused on the two voltages ( and crow-bared on the +7).

Very reliable connection needed (10,000 connections to do)

Use faston connections for individual boards

inside iron gaps.

Boards from the last three layers in the barrel and vertical strips in the end-caps are located in small crates on the outside of BaBar.

Power cables for the iron gap FEC’s go through the conduits used to extract signals, in separate compartments. Plenum rated cables (Belden parts # 83503) are used.

12 conduits on each end (+z and -z) carry the cables to the outside world in the barrel and three conduits are used for each half end-cap.


Boards power distribution Boards power distribution (cont.)(cont.)

In the barrel each conduit has a fan-in/fan-out device sitting on top of the wire-ways

24 (12 on each end) of those distribution points have to be equipped. One distribution point power 48 iron gap Fec’s (layer 1-16) and one minicrate (layers 17,18 19).

One sextant is serviced by 2 distribution points connected to DIFFERENT power modules.

In the end-caps, each half door has three distribution points for the iron gap FEC’s. (Each of these has to feed 72 negative FEC’s).

All the positive FEC’s in the end-caps are in minicrates , so individual connection for series of those are foreseen.

Distribution points were designed so that a max. current between 20 and 25 A would be split in them: this figure sets the gage for the interconnecting wires.


The single barrel conduit The single barrel conduit distribution box distribution box


The power distribution on one The power distribution on one end of the barrel (conceptual)end of the barrel (conceptual)


The power distribution on one half The power distribution on one half the back end-cap (conceptual)the back end-cap (conceptual)


The power distribution on one half The power distribution on one half the forw.end-cap (conceptual)the forw.end-cap (conceptual)


Components inventory and Components inventory and purchasingpurchasing

Item Bought at Code number Unit

Needed (Barrel only) Ordered On hand To receive Used Left To reorder Price/unit

LV distributionP.Supply to boxBlack wire AWG2 (GND) SLAC stores 61-328-372-01 FT 1000 485 515 0.54Red wire AWG2 (+7V) SLAC stores 61-328-372-03 FT 1000 827 173 0.54White wire AWG2 (-5.2V) SLAC stores 61-328-372-02 FT 1000 1000 0.54Connection lugs Buckles-Smith (*) GB Electrical 14-801 EA 72 150 150 3.47Heat-shrinking tube SLAC stores 47-224-400-18 4' 10 10

BoxesSteel box Electrical Materials, Inc. 8106RHC EA 24 40 40 28.14Inner plate Electrical Materials, Inc. N108P EA 24 40 40 2.47Nylon grommets Newark 96F7217 Roll/25' 3 3 4 22.75Contact strips Newark 82F9833 Roll/100 8 9 8 1Standard tracks Newark 82F9834 3' 10 11 1 9 1End stops Newark 82F9836 Box/100 2 2 2Flat faston tabs Newark 96F7925 Box/100 8 8 1 7 27.21Faston tabs 45 deg Newark 87F2455 Box/100 8 8 1 7Faston tabs 90 deg Newark 95F1128 Box/100 8 7 2 6 30.56Faston jumpers Newark 87F2458 Box/100 7

DaisychainsFastons AWG14 SLAC stores 59-294-751-02 Box/100 12 12 9.67Black wire AWG14 (GND) SLAC stores 61-328-365-01 Spool/500' 1 1 19.40Red wire AWG14 (+7V) SLAC stores 61-328-365-03 Spool/500' 1 1 19.44White wire AWG14 (-5.2V) SLAC stores 61-328-365-02 Spool/500' 1 1 21.13

LV to MinicratesFastons AWG12 SLAC stores 59-294-751-03 Box/100 1 2 2 18.20Black wire AWG12 (GND) SLAC stores 61-328-366-01 Spool/500' 0.2 1 1 27.80Red wire AWG12 (+7V) SLAC stores 61-328-366-03 Spool/500' 0.2 1 1 31.75White wire AWG12 (-5.2V) SLAC stores 61-328-366-02 Spool/500' 0.2 1 1 29.45

(*) (408)280-7777 John, X107

HV distributionHV plastic boxGround lugs SLAC stores 59-294-707-50 Box/1000 1 1 1 213.50Ground lugs Newark 50N454 Box/100 1 1 9.78

Current Monitor cablesIDC 14 poles Newark 46F4656 EA 200 200 1.77Strain reliefs 14 poles Newark 46F4666 EA 200 200 0.20Cable 60 pairs Newark 97F8632 Spool/100' 15 7 8 38.03IDC 64 poles w. strain relief Allied 515-1956 EA 32 2.29


Fast tour of componentsFast tour of components

3 conductor cable Plenum Belden parts # 83053

Faston and faston blocks AMP parts #

Metal containers for faston blocks

Connection wires to the power modules: AWG 2 10 m. power supply distrib. Box AWG 10 5 m. distr. Box barrel minicrates AWG 2 5 m. power supply end-caps minicrates

Power supply modules Crates 6U and 3U eurocrate standard with slides Monitoring cables

buffer amplifiers to match GMB’s input range

Fan unities 12 (one per crate) Solid state relay to remotely turn on crates

Din Rail power supplies switches and cables (12) Interface for software turn-on.


Installation scheduleInstallation schedule

Power supply modules: 80% purchased; 70% at SLAC

Cables: FEC’s connection purchased ; harness in

production at Naples. Supplies-distributors on hand (SLAC store)

Contact blocks: purchased, being delivered at SLAC (Anderson)

Faston purchased being delivered at SLAC (Anderson)

Crates Purchased being delivered at Frascati Some work to do on the to punch holes slots etc.

ready by the 10th of January.

Prototype crate (BPSM) ready with all the cabling /monitoring before

Christmas.

Few BPSM ready at SLAC by end of January.


ConclusionsConclusions

The low voltage system for the FEC’s is essentially designed; prototype is finished and production is ready to go.

In spite of the standard type of requirements, practical design has presented few challenges mainly due to the sizable amount of power one has to produce and distribute.

Solutions have been chosen to maximize reliability and ruggedness of the plant.

With our design we’ll be able to handle single boards connections from the outside of the detector .

Reliability of the active parts are well above the limit we could have tested with the RPC quality controls runs during production.

the babar ifr low voltage system

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