DSS Advisory Board 06.10.2003Christoph Schäfer

Rack Safety System

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Introduction

The Rack Safety System is a proposal of CMSand was discussed during the September CMS

week in detail.

It does not replace the Rack Monitoring and Control System

(RMCS),but it’s a complement and collects all directly safety relevant signals

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Philosophy

Detector Level: DCS & DSSRack Level: RCMS & RSS

Split purely safety relevant informationfrom monitoring & contol information

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reads out the ELMB’s two temperature sensorsspeed of tangential fans humidity sensor, etc.

cuts power to rack(s) via software

allows for trending and preventive maintenance

Rack Monitoring & Control System

The RMCS could be seamlessly integrated into the DCS

Hardwired safety signals could be integrated into a Rack Safety System (RSS)

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Smoke Sensors (2 per rack, logical AND)installed by ST/MA (Centrale Incendie)

Thermal Switchprovide current loop

Signal from the Detector Safety System (DSS)

RSS stores the rack map

RSS Inputs

The RSS has to deal with 3 inputs/rack

and should memorize all inputs

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cuts power to rackby sending first a signal to DCS in order to shut down power gracefully and after adjustable delay hardwired cutelectronic equipment is best protected

enables power to rackstriggers fire extinguishing system

foreseen for all UXC racks from the beginning

RSS ActionsThe RSS has to trigger 2 actions/rack

Flexible logic needed

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Each rack (320) and AC/DC converter (400) is controlled by a remotely controlled relay

each relay can be opened/closed by a current loop provided by RSS

RSS and all realys are in the service cavern

ST/EL uses only RS485 to power on/off racks and AC/DC converters (granularity to be defined)

Power Cut

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CMS uses exclusively the RSS current loop to switch on/off racks and AC/DC converters

CMS has priority to keep rack or AC/DC converter off

Power Cut

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Inside a rack there is no relay but a Power Distribution Chassis (PDC)

A PDC comprises 5 manually resettable fuses:

turbine

3 crates

distribution box

Power Cut

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Number of Channels200

US racks120

UX racks400

UX ADC

smoke detection 200 120 80

thermalswitch 200 120 400

fire ext. none 120 ?

DSS 40 30 80

grand total: 2110

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All necessary functionality of RSS already incorporated in DSS

Essentially no development for RSS needed

ELMB card read out by the RMCS, no modification necessary

RSS = DSS Clone

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Power

Thermal SwitchT

TTT

DSS

RSS

DCS

E Fire Extinguisher

E E E

Smoke SensorS

Centrale Incendie

S S S S S S

DCSELMB ELMBELMBST/EL

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Fire Extinguishing

DetectionLine

RSS

N2

orFM200

Gas Line

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Rack Monitoring & Control Systemuse current ELMB cards, no modification

Rack Safety Systemuse existing DSS hardware, no developmentabout 2000 channels

Summary

This CMS proposal covers: