Bulletin 48B03A00-01E-H

P r o S a f e - S L S , S O L I D S T A T E S Y S T E M C O N C E P T

A DETAILED LOOK AT ProSafe-SLS

Yokogawa servingIndustrial Safety

The company

Yokogawa participates in all industriallandscapes in the world. Even more, Yokogawais a leading supplier in test and measurement,industrial automation and information service inthousands of advanced production processesall over the world. Yokogawa employs approx.19,000 employees world-wide. Yokogawa isone of the world’s most experienced Safety andControl firms and has acquired a history of over40 years in supplying Safety Systems. We arecommitted to offer cost effective protectionsystems for all the Safety Integrity Levels (SIL 1-4) for the oil & gas, petrochemical, chemical,nuclear & conventional power industries. Thecapability to offer integration of Safety systemswith process control systems is especiallyappreciated by our customers.

Yokogawa will combine the know-how andexpertise related to total automation solutionsfor the process industry, including manufacturingexecution systems, distributed controlsystems, safety systems, SCADA systems andFOUNDATION fieldbus instrumentation.

Enterprise Technology Solutions

Our customers have valued Yokogawa’sexperience with integrated system solutions formany years. Our total integration capability isknown as Enterprise Technology Solutions(ETS). It includes products and services,ranging from the design and manufacture offield instruments to process control systems,Safeguarding systems, Supervisory & DataAcquisition and complete ManagementInformation Systems.Yokogawa’s ETS concept provides all theelements you need to minimize risk, to optimizeperformance and maximize the profitability ofyour plant.

Safety assessment

Safety Instrumented Systems play an increasinglycrucial role in many process plants today.Safety standards such as IEC 61508/61511and ISA 84.01, that have world-wide recognition,are creating more stringent Safety requirementsfor process plants. Therefore, users in theprocess industry are looking for system suppliersunderstanding the Safety standards and offeringsolutions to meet the Safety requirements.Yokogawa offers at Yokogawa Service CenterEurope a department of specialists toguarantee adherence to the Safety standardsand to issue a Safety Assessment Certificate foran individual application.

The ProSafe products

Yokogawa has created the ProSafe products,to cover all requirements in today’s Safetysystems. ProSafe consists of two product lines,the ProSafe-SLS and the ProSafe-PLC. Eachproduct line covers specific requirements forindividual Safeguarding systems.

The ProSafe-SLS offers a superior solution inSafeguarding System applications that requirea SIL 3-4 or TÜV AK 5-7 rating. These high-integrity Safety systems are appliedin the oil and gas, petrochemical, chemical andconventional & nuclear power industries, such as for:

• Emergency-Shut-Down (ESD) systems inSafety critical process units;

• Environmental & assets protection systems;• Burner Management Systems for incinerator

furnaces and boilers;• Compressor protection systems for rotating

and piston type compressors;• PSD & ESD at Offshore platforms and Floating

Production, Storage & Off-loading Vessels (FPSO);• High Integrity Protection Systems (HIPS) for

critical processes and pipeline protection;• Wellhead protection systems, sub-sea

systems;• Natural gas (LNG) storage & loading

installations; • High Integrity Protection Systems in

Chemical process plants; • Replacement of Relay systems.

Today, over 1000 ProSafe-SLS systems have been

installed in the world protecting people, the environ-

ment, valuable assets and production installations.

YOKOGAWA’S OFFER TO THE CUSTOMER:

ProSafe-SLS provides the ultimate solution, when Safety allows no compromise.

The ProSafe-SLS is a Safety InstrumentedSystem that is developed for applications,which require the highest Safety Integrity Levels(SIL 3 & 4). It employs solid-state elements toprocess the functional logic. This technology iscapable of executing all typical Safety tasks, aswell as the related supplementary Non-Safety-Critical functions. This comprises interfacingwith a Human Machine Interface, ProcessControl System, Sequence of Event Recordingsystem, SCADA system, etc.The sophisticated design and superior Safetyperformance have created the Safety referencestandard for solid-state Safety InstrumentedSystems.A radical Safety achievement, is the eliminationof software for an operating system and for self-diagnostics. Instead, a unique inherent self-testtechnology is employed, throughout all Safety-related parts of the ProSafe-SLS system.

The modular design allows the creation of fault-tolerant structures to achieve very highavailability, without affecting the superior Safetyperformance. A 1oo2, or 2oo3 configuration, asdefined by the standards IEC 61508/61511and ISA 84.01, allows the connection of redun-dant sensors and actuators in a very cost-effectiveway. This will balance the availability of thesefield devices with the high system availability ofthe ProSafe-SLS system. In these redundant structures on-line repair ispossible in order to restore the original fault-tolerant architecture, without a shut down of theprocess.

Safety-by-design

Fault-tolerance by redundancy creates veryhigh availability

The ProSafe-SLS system conceptThe SLS (Solid State Logic Solver) System wasdesigned with the objective of establishing anuncompromising safeguarding system, of whichthe Safety Integrity Level is eminent andverifiable. The ProSafe-SLS concept has successfullyeliminated all known sources of unsafe failures. Ineach logic processing system the inherent self-test is performed, while working with the realfunctional logic of the application. This furtherimplies that logic processing and self-test isexecuted at exactly the same moment intime and by the same components of thehardware. During every scan, whichtakes only one millisecond, the systemoutputs are recalculated by execution ofthe complete functional logic. In this way,the Safety critical parts do not requirememory elements to store the results ofthe logic solver over a period longer than onemillisecond. This unique inherent self-test technology, whichis employed in the SLS concept, has created therobust Safety achievement that eliminatespotential Safety hazards.Non-Safety-Critical functions and computerinterfaces are implemented with microprocessortechnology.

The SLS magnetic coretechnology

The SLS is inherently fail-safe

This unique technology is called “inherently fail-safe”, meaning that by the self-testing natureof the basic circuit it will act fail-safe, withoutthe necessity of utilizing additional test- ordiagnostic circuits. The logical signal status,which reflects the ‘safe’ condition of criticalprocess parameters, is represented by pulse-trains. In this way all the circuits remaindynamic continuously, during normaloperation. The logic solver functions are processed by bi-stable magnetic core elements, which have

inherent fail-safecharacteristics.

Amplifyingtransistors

serve only to restore the lost energy of thepulse-trains that have passed through thesemagnetic logic elements.

SLS when Safety

allows no compromise

The essence of the ProSafe-SLS,solid-state logic solver

The basic principle (MagLog) was invented in1965 and has been utilized in a large numberof SIS installations in the hydrocarbon, thechemical and the (nuclear) power industry.This technology, based on magnetic logic,has been upgraded using up-to-datecomponents and fabrication methods,without changing the unique inherent Safetyprinciple. By the simplicity of the fundamental principle,it allows any method of in-depth Safetyassessment and verification. The SLS systemhas scored highest on the scale of Safety,using the traditional qualitative methods, andexcels even more if the up-to-dateQuantitative Risk Assessment methods areapplied. These methods are recommendedby the IEC 61508/61511 standard.

The Communication interfaceProSafe-COM

The functions of Communication, Sequenceof Event Recording and remote Input andOutput functions are realised by the ProSafe-COM modular system. The specific functionsare implemented by software and dedicatedmodules of the ProSafe-COM system.An open communication structure with othersystems is created by the support of commonlyused industrial communication standards,such as ModBus, Ethernet and OPC.

Further ProSafe-SLS systemqualifications:

Full compliance with the recommendations ofthe following guidelines for SIS systems:

• IEC standards 61508 & 61511;• ISA standard 84.01;• HSE, Health & Safety Executive, PES/SIS

documents 1 and 2;• EEMUA Publication 160 – ‘Category 1’

applications;• Standard engineering practices, as

implemented by prominent operatingcompanies.

In addition, the ProSafe-SLS system wasassessed successfully for Safety & Availability

by the following organisations and others:TÜV, SINTEF, TNO, WIB, KEMA.

Unique reputation of the ProSafe-SLSby following features:

• Superior fault-tolerance for Unsafe faults,which puts it in SIL 4 & AK 7 Safety categories;

• Mean time between testing according to IEC 61508 methodology typically exceeds 10 years;

• High Availability (or low False Trip Rate) by lowparts count and reliable design. Furtherimprovement can be achieved byredundancy of associated field devices;

• Robust for harsh environmental conditionslike extreme temperatures, EMI, etc.;

• No software in safety functions, therefore nocostly updates;

• Fast response-time independent from systemsize or I/O count;

• Integrated computer interfaces & Sequenceof Event Recorder;

Auxiliary non-Safety related Inputsand Outputs

Additional modules and the ProSafe-COMsystem can handle non-Safety-critical I/O in acost-effective manner, such as for the controlof annunciation matrix and mimic panels andfeatures:• Bi-directional serial communication with

other systems, operating as a master or asa slave, utilizing the ModBus protocol;

• Handling of Non-Safety-Critical functions;• Standard alarm sequences & first-up

handling and other functions, which arereadily available in the engineering tool;

• Point-to point connections by dedicatedmodules.

• Simplicity makes it easy to service by normallyskilled people;

• PC based engineering tool keepsdocumentation up-to-date;

• Product lifetime: we still service systemsdelivered in the early seventies;

• Low power consumption;• Independently isolated Inputs & Outputs;• System size often smaller than a PLC

solution;• Impressive list of reference projects at

reputable companies on all continents andoffshore.

Project realization with the SystemEngineering Tool, ProSafe-SLS SET.

The engineering of system applications is fullysupervised by the PC based, SystemEngineering Tool (SET). The tool allows theproject engineer to fully employ his expertiseand preferences for system layout and thecreation of autonomous sub-systems. At all times, during not only engineering but alsoextending to the whole useful life of the realizedproject, ProSafe-SLS SET organizes theconsistency of project files.

Specification highlights:

Principle of operation Magnetic cores serve as logic processing elements;

Inherent self-testing in Fail-safe Inputs & Outputs.

Special Features Inherently fail-safe;

No system software in Safety-Critical parts;

Galvanic isolation of I/O and logic-solver.

Electromagneticinterference High immunity to EMI, >30V/M.

Operating Temperature -20º C to +70º C.

Number of Inputs & Outputs Unlimited.

Input rangeDiscrete: 24 Vdc.;

Analogue 0-20 mA, 0-10 V or 0-5 Vdc.;

Communication: Inputs via ModBus and Ethernet interfaces.

Output rangeFail-safe: 5 Watts & 20 Watts; 24 Vdc., 48Vdc. or 110 Vdc.;

Relay: DC and AC;

Communication: Outputs via ModBus and Ethernet Interfaces.

Timer Range 7 millisecond to 70 hours.

Scan-time 1 millisecond for I/O scan and Safety logic processing; independent of number of I/O.

Auxiliary modules for Line-fault detection. Microprocessors for non-critical functions such as: Annunciation, Communication & SER-Diagnostics.

Engineering tool ProSafe-SLS SET logic symbols related to the SLS circuits.

Programming Hardwired programming of the Safety

Interlocks with protected (IP 20) cold crimp contacts.

Safety certification byTÜV: AK 1-7 based on VDE/DIN V 19250;

Factory Mutual: SIL 1-4 based on IEC 61508 & 621511.

Yokogawa has engineering offices andproduction facilities for Safety Systems in theNetherlands, Japan and Malaysia and operatesvia the world-wide network of Yokogawa Salesand Service subsidiaries. Our project organization operates on a world-wide basis and has a strong commitment toquality and is ISO9001 certified. The activitiescomprise the realization of turnkey projects,after sales service and technical customertraining.Through the Yokogawa offices and the regionalYokogawa subsidiaries, we provide advice onSafety assessment and related issues.

Customer support and training

When the installation is operational, our TrainingDepartment provides tailored courses foroperators and maintenance staff. Experiencedinstructors provide training at a Yokogawatraining center or on site, anywhere in the world. By service contracts that guarantee a quickresponse time, our service engineers canensure continuous operation of the installationand carry out modifications that may berequired.

Project organization

Printed in The Netherlands, 02-207 (A)BU 48B03A00-01E-H Subject to change without notice. Copyright ©

Yokogawa System Center EuropeYokogawa System Center Europe B.V.Lange Amerikaweg 55, 7332 BP ApeldoornP.O. Box 20020, 7302 HA ApeldoornThe NetherlandsTel.: +31 (0) 55 538 9500Fax: +31 (0) 55 538 9511E-mail: Info@yokogawa.nl

Yokogawa Industrial Safety Systems Sdn. Bhd.No. 8, Jalan 12/91A, Taman Shamelin Perkasa3 1/2 Miles, Jalan Cheras56100 Kuala LumpurMalaysiaTel.: +60 (0) 3 9200 2100Fax: +60 (0) 3 9200 5100E-mail: Info@yokogawa.nl

Yokogawa Electric CorporationIndustrial Safety Systems dept.Industrial Automation Systems Business Div.2-9-32 Nakacho, Musashino-shi, Tokyo180 8750 JapanTel.: +81 422 52 5816, Fax.: +81 422 52 0571E-mail: Prosafe@csv.yokogawa.co.jp

For more information:www.yokogawa-europe.com