TECHNICAL WHITE PAPER INTRINSICALLY SAFE FIELDBUS IN HAZARDOUS AREAS Decision Guidance for Intrinsi cally Safe Fieldbus Solutions Currently di fferent solu tions are available for i trinsi ally safe
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TECHNICAL WHITE PAPER INTRINSICALLY SAFE FIELDBUS IN HAZARDOUS AREAS Decision Guidance for Intrinsi cally Safe Fieldbus Solutions Currently di fferent solu tions are available for i trinsi ally safe

This pa per chrono logically accounts the history of all intrinsically safe explo sion pro tectio n concepts fo r fieldbus and gi ves an outlook on DAR and the redundant F SCO concepts The pa pe r then go es on to co mpare all methods oneonone wi th

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TECHNICAL WHITE PAPER INTRINSICALLY SAFE FIELDBUS IN HAZARDOUS AREAS Decision Guidance for Intrinsi cally Safe Fieldbus Solutions Currently di fferent solu tions are available for i trinsi ally safe




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Presentation on theme: "TECHNICAL WHITE PAPER INTRINSICALLY SAFE FIELDBUS IN HAZARDOUS AREAS Decision Guidance for Intrinsi cally Safe Fieldbus Solutions Currently di fferent solu tions are available for i trinsi ally safe"— Presentation transcript:


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TECHNICAL WHITE PAPER INTRINSICALLY SAFE FIELDBUS IN HAZARDOUS AREAS Decision Guidance for Intrinsi cally Safe Fieldbus Solutions Currently di fferent solu tions are available for i trinsi ally safe fieldbus like Entity, FIS O or High-Power Trunk and recently an- nounced r dundant FIS O and DAR concept . This pa per chrono logically accounts the history of all intrinsically safe explo sion pro- tectio n concepts fo r fieldbus and gi ves an outlook on DAR and the redundant F SCO concepts. The pa pe r then go es on to co mpare all methods one-on-one wi th a pra ct ical view on

their meri ts and drawbacks. This paper i directed at technical decision m kers involved in planni ng fieldbus topo logies for the hazardous area i search of solutions. 28/07/2008 ED M TD 548_ ENG 211701 Prepared by: Armin Beck Product Portfolio Manager – Fieldb us Infrastructure Andreas Hennecke Product Marketi g Manager – Field us Infrastructure
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Peppe l+Fuch s is the prove ma rket l er for i nnova ti ve and hi ghly available com one ts for y ur fiel d- bus ac cor in g to IEC 6115 8-2. With qua ity compone ts to fit your pro ess automation system and de- man s in th e field

our hig reliabl a ene gy -efficie t desi gn allo ws you to fo cus on th e task at han . Knowi that your fi eldb us is run in g. The High-Pow er T unk Concept with Entity or FISCO devices: Connect the ma mum nu mb of vic s to the same field us t unk; an d at the s me time ma ke us e of ma ximum cabl e le ngths . This concept utilizes stand rd po r s pplies s ch as the easy to install an d config uration free Powe r Hub. Segment Protectors and FieldB arri ers a install d close to fie d d vices an d limit the en ergy at the s ur. You are f to work on fiel d devic s witho t hot wor pe rmit. D T c

o y f i T l i b t ency to field us. S ee d up commissionin g with auto ted doc me nt ation. Meas ur e field us per orma nce d de te c ge s in the con l oom be for the b come critical to your plants o ation. You ca n rely o pro ts b ilt to serv your ev y n in fiel db us fo r pro ess aut mation. Yo u can g in from the expe rien ce of kno led ble e ngin s to cr eate your fiel db us solution . You can b at ease with pro ucts and solutions fr om Pe pp er Fuc
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in sa Fi in Hazardous Areas Intro uction Table of C ntents Introducti on

.................................................................................................................... Entity .............................................................................................................................. 2.1 Descri ion ......................................................................................................................... 2.2 Appraisal ............................................................................................................................ FISC O – F eld us Intrin sic lly Safe C ept

........................................................................ 3.1 Descri ion ......................................................................................................................... 3.2 Appraisal ............................................................................................................................ Redundant FISCO ............................................................................................................. 4.1 Descri ion

......................................................................................................................... 4.2 Appraisal ............................................................................................................................ The High-Pow er Trunk Concept .......................................................................................... 5.1 Descri ion .......................................................................................................................... 5.2 Appraisal

............................................................................................................................. DART – Dyna mic Arc Recognition and Termination ............................................................... 6.1 Descri ion ......................................................................................................................... 6.2 Appraisal ............................................................................................................................ Technical Comparison

...................................................................................................... 7.1 Gene ral pe rfor man of the intrin si cally s fe fiel dbus sol tions ............................................. 7.2 Compa ison sed on re al-li e a plication re qui rem nts ....................................................... Concl si on ...................................................................................................................... References ......................................................................................................................

2008- 7- 28 EDM TD 548_ ENG 211701 ww w.peppe l- fuchs. com 1/9
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Intro uction Intri sically fe Fiel db us i Ha zardous A eas Introduction Process production plants are het ro geneo s and compl x in many r spects: field d vices of very differ nt types ar e mo unte d alon gsi e co n- ventional motors an d sim le digital s nsors. Sites pla e re qui rem nts fo r lon c ble l ngths distributed across buildi ngs and floors, with installation i safe nd e osion- ha ou s areas with th eir stringent safety regul ons. In short, a typical plant layout consists of practi- cally a y type of

ap plicat io n, a nd this ha s to be taken into conside ation when signi ng an installing fiel dbus systems. Limiting the amount of en ergy in a ha rdo s ea w in in sa is ba rr ie h s bee aro since the 196 ’s, a nd thes circuits are e sily validated by c mpa in g the safety pa ram ters of the powe r s ur ce, with t ose of the suppli d appa ratus an d the co nn ect ng ca- ble. Howeve r, a field us is tradition lly a net work with tr unk- an d-s ur t pology whe e each device is co ect d to a h me run cabl e via dis tribution interfaces. To validate the overall i trinsic safety it is requi red to

compile all field devices a ca bles saf ty pa ra mete rs, a match them agai nst the power so urce. In the begi nnin thi effort an d t e very low a ount of ene gy i itiall y availabl e prohibited application of fie in ha ou s ar ea s. Today the m rket is able to look ba ck o a re sp ec ta e an d r ve lop en t of in tr in sic lly safe field us imple ent tion. This pa r pro- vides an overview on how this technology has improve to the point wh ere today it is meetin the techni cal requireme of modern pro ess plants. It considers techni cal specificatio ns and output r leva nt to se gme t layout an

d desig and com es individual solutions. Latest devel- opme nts ar e desc ribe d, w ich will prov ide fur- ther enha nce ents to the process in dust ry. Entity 2.1 Descri ption The Entity model as d fine by IEC 60 079- 11 [5] is a method of validating an stallation of intrinsi- lly sa fe an d a ssoc ed ap pa ra tu s thr h th e use of i trinsi cally safe parameters. In additio to the devices parameters t e cable capacitance and in ductan ce is assume d as bei conce trated a nd h s to be considered as well. Simpli- fications for Fieldb us we re n t considered within this specifi ion an d pl nne

rs ha d other option than to accept the co mplex and ti me con- suming calcul ation efforts t validate an i stalla- tion. The first initiative to broadly define standardi ed IS parameters for fieldbus was started by the rele ase of the FOUNDATION fieldbus FF-816 Physical Laye r Profile [2]. B sed on the co nserva tive Entity model this doc me nt re com en de safety parameters of U = 24 V, = 2 0 mA an d = 2 W for powe r su lie used for gas grou IIC (g roup A, B) applicat ions. Developi ng Entity compli ant fiel db us prod uc ts by observing these va g t mu ea sie how ve the ma mum available pow

r of 1.2 W co ntinued to be a limita- tion, preve ting re asona le us e. ses of grou p IIB ( ro up C) need more e ergy to ignite. In an attempt to overcome the 1.2 W limi- tation one manufact urer intr od uc ed a IIB Entity powe r s ly . Wiri ng block furth r li mited the er for II C tity fie d devic s. ng ha to be locate d in a IIB location even for I C a ppli tions. 2.2 Appraisal Applying the Entity model t fieldbus i practical applications i rathe rare , there a e o ly a few power s ppli es confo ming to the Entit model available tod y. Typically t ey provide 1 …12 and 7 …1 00 mA whi h is

just eno gh to oper ate 2...3 field devices per segm ent (gas gro p IIC). In the end Entity: Prov ides po r fo r s gm ents with up to 3 instruments Requires a significant calculation effo rt to validate i trinsic safety IIB solution offers more pow r, howev r not suita le w ere ma ny applications re- qui re g ou p II C From a market point of view the limitati ons pre- vented th e conservative custome bas from really ado tin int insically safe fiel db us when it was eval uate d for use i haza rdo s are s. This restraint was intensified by the high initi l cost of intrinsicall y safe techno logy

in gene l. The very nat re of the elect al d sig in cludin g double (Ex ib) or triple (Ex i ) redundant circuits for current limitation and constant voltage to- gether with galvanic isolations were inv king a high effort with a direct in flue nce o th e cus- tomer’s e pe nse. Com are to the expense of using traditional protection methods s ch as Ex e and Ex d nd no n-i ce ive field wi ng the technology w s not com et itive at all. 2/9 ww w.peppe l- fuchs. com 2008- 7- 28 EDM TD 548_ ENG 211701
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Intri sically s fe Fiel db us i Ha zardous A eas FISCO – Fiel db us Intri sicall y

Safe Concept FISCO – Fi eldbus In trinsically Safe Concept 3.1 Descri ption 7- 28 EDM TD 548_ ENG 211701 Utilizing fiel us i ge ner l for pla t ins rum tation became globally mo re and more po pula r in the early 1990s. For fieldb us in ha zardo s area applications h wever a feasi le solution s still missing. Fast adoption of fieldbus t chnolo gy in factory automation caused a desi re to reevaluate the application of fieldb us in process a toma tion as an alte rnative to 4…20 interf ace te ch nology. Prelimi y experim nts cond ucte by the Physikalisch Technis he B esa stalt (PTB), Germa y sho

ed that lo cabl e le ngt hs con nect ed to a powe r sourc did not si gn ificantly increase the ince ndivity of a spark. Un der the premise to re check the con ervative approach of Entity with co nce trated ca ble ind ctan ces an d ca pacita nces and with th e objective to s mplify system calcul ations and to allow more power in the field, PTB asce rtain d e pe rime ntally new IS pa ram ters fo r fieldb us wit the following objec tives: Incre se avail ble po wer Stand rdize the install tion para mete rs and limits Simplify system calculations and docu- mentation The results of this study were

publish d as a report by PTB in 1994 [1 ]. Two years lat r Pep- pe rl+F uchs i trodu the first power supply compatible with the re port’s requireme ts (Figure 1). Analo to Entity one ma fa cturer de ded t provide a II B FISCO soluti on. This approach effec- tively offered more e gy to the field e abli ng longe r tr unk len ths a more fiel d devices. Entity field d vices are int rfa usin special “add -on coupl rs”. The field us i stallati on ha to be located in a IIB loc tion. F rthe r spe ial activ wi ring interfa es w re re ire to take fieldb us s urs into a I C e ronm ent. FISCO pres cri es

that only one pow r s pply is pe rmitted pe r fieldb us se gme t an d that all other devices are powe r d ns with meas ures in pla e preve ng uninte ntional pow r f eed bac to the ca ble. F r the first time a stan da rd pl aced actual restri ctions on cabl an d el ect ic appa ra- tus with regards to para sitic ca pa city an d ind tanc e. Inst ruments a nd power s pplie requir certification through a no tified body. Ca bles are docume nted t rough a de cl aration by the man facturer. Figure 1: First FISCO power su pply KFD2-BR Ex1 3PA.93 FISCO validation of intrinsi c safety is limited to the

docume ntation of FISCO complia of all hard wa re inv lv ed. L ter the F SCO re port tur ed into the tech nical s ific ation IEC TS6 0079- 27 d ad op ted in the ye ar 2 a sta da rd IEC 60 079-27 ]. 3.2 Appraisal FISCO offers t e easi st method for vali dation of explosion pro ection, which ex plains its popul ar- ity. It shifted the bulk of the respo sibility for soun d ele tric desig fro the pla r nd o erator of process pla ts to equipment m fac- ture rs. FISCO improve the available IS powe r. Unde r re al-lif e conditions i is suitable for small applications with very short cabl e len s and

4…8 d vices pe r se gme t de pen in g on the g gro up it is used in. (S for Re al-L ife app ica ion on page 8). sp ite of the im ovem ts offe b FI SCO a real bre akth ough of int sically saf fieldb us failed to appe ar. This was d e to the fact that the expected savi ngs in install tion cost and effort coul d not be realize , even if FISCO allow prac- tically the operation of twi e as ma ny field in- struments when compared to Entity. Further other dis dva tag s move d to the fo re gro which h ven’t changed wit the i troduction of FISCO: No po wer s pply red nda nc y. Powe r s p- ply as single

point of failure ww w.peppe l- fuchs. com 3/9 2008-
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Red t FI SCO Intri sically s fe Fiel db us i Ha zardous A eas Very little flexibility in segment design be- ca use mix of d vices fo r saf an d h za rd ous areas on one segment is not permit- ted 7- 28 EDM TD 548_ ENG 211701 Ope ation of more field d vices but still marginal co ed to 32 possible d vice s as d fine d i t e fiel db us st and rd IEC 61158-2 [4]. Ne of sp ec ia l “a dd de vic s for si- multa eo us use of FISCO a d Entity fiel d devices. Redundan t F SCO 4.1 Descri ption The de man f r high availa bility for ma

pro ess applicatio ns lead to the concept of red n- dant FISCO power s pplie . To achieve red dan y of pow r supplies fo r a FISCO seg ent it must be ens red that o ly one pow r supply is active at any time. For du nd an t FI SCO tw o in trinsically saf po wer s pplies are managed by two arbitration mod les. T e arbit ation modul ens re that only one pow r supply is switche onto the fiel db us se gme t at any given time. They monitor the voltage output level of each supply, an d in the event the voltage level of a supply falling below a spec ific level the switch over is initiated bet een the

two interacting arbitration modul s. t c a r s o t switch of th e active arbitration mo dule opens and after a fi nite period of time the other one closes. (See F gure 2). For a short period of time the fieldbus l ooses power and the seg ent volt- age dro s. As a rule of thumb, 10 0 s is pe rmis- sible as maxi mum glit ch time to avoid field de vices res tting due to a po wer loss. However the red nda ncy tr ansfe will have a significa nt influ- enc on the c mmunication s by destroyi ng t le- gra s with very high pr obability due to the powe r dro . The FISCO stand I C 6 0079- 27 perm

its only one powe r pply pe r el ect ic circ uit [3]. This is ens re d by t e a bitration mod les, wh ich will re qui re c rtifi ation by a no tified body. Timing is critical and the hardwa m b c tested to en sure ex plosion protection during red nda ncy tr ansfe . Figure 2: Red ndant F SCO Principle Diagra m 4.2 Appraisal Com ar ed to FI SCO w th si su pp lie four ele troni modul s are required to provide red nda ncy. This req ires about 3 times more cabi net s ac for the s me numbe of fi eld de- vic s an d the sa me ble le ng ths. Re du nd an t FISCO ca n b classified as inte rim sol tion

for applications with the sa me re quirem ents as FISCO an d a nee for hi gh er pla t avail bility. du nd an t FI SCO c ar es to sta FI SCO a follows: Not certifie d yet, test metho s are n eed ed to verify funct onality and i trinsi c safety of p wer supplies and arbitration modu les Same limitations with regards to cabl e length a n mbe of devic s as FISCO An extension to the cu rr en t FI SCO stan dar m y be re qui red fo r gen l ac ce tance High probability of commu nication e rror du rin red nd ancy tra sfe Arbitration m dules re qui re extra po we r which is drawn from th e segment

putting furthe r co nstraints on ca bl e len th an numbe of dev ces Significa ntly more ca binet spa e re quire Higher ca pital cost 4/9 www.pepperl-fuchs.com 2008-
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Intri sically s fe Fiel db us i Ha zardous A eas The High-Pow er T unk Con ept The High- ower Trunk Concept 5.1 Descri ption The High-Pow er Trunk Con ept (HPTC) was intro- duced in 2002. It removed the limitatio s with reg s to segme t len th and n of de- vices. Fieldbus in hazardo s area a ppli ations was more co mmonly acce pted aft rwards. HPTC was developed and intr oduc ed by Pepp erl+Fu s (See Fig re 3). 7-

28 EDM TD 548_ ENG 211701 The pri ci ple idea of the HPTC is to deliver en ergy on the fi eldb us trun k not limited for ex plo- sion protectio close i to the haz rdous area. Within the h zardous area it is distrib ted via energy -limiting wiring interf aces to its final des- tination, the field inst rum nt. The t un k is in stalled utilizi ng increased safety methods (Ex e) and is the ore prote te d fro m chanical dam ge an d effects s ch as uninte ntional dis- conn ect or cor osion et c. Com ar ed to ll othe in tr insically safe i stalla- tion methods stand po wer s ppli s can be applied for

th e HPTC, which are m ch sim le r by desig a nd available at a lo w price. For Z ne 1/0 (DIV 1) appli ations the wiri ng interface, t pically calle d FieldBa rrie is used and a ts as d stribu- tion interface providing fo ur galvanically isolated outputs certified Ex ia IIC ’. Each o tput acts as inde pe nd ent F SCO or Enti ty pow r s pply Up to four Fiel dBa rriers m y b o ate on o e s ment, allowi up to 16 IS field devices and a overall maxim cable length of 1900 m. The HPTC e les high er availability of the field bus se gm ent as the po we r supplies may be op- erate in red t config

uration. Conn ecte d i pa rallel both powe r s ppli s shar e the lo ad cu rent. I the event of a power supply fail ure the other s pply t akes ove im mediat ely wit out a interruption. Additionally the life expect ancy of the powe r s ppli s is long er in red nda nt con figuration due to the sh ared lo wer co inuous provide current whi h is h lf of the act al load cu rr ent. 5.2 Appraisal The intro uction of the HPTC c ed the br ak through an d gen ral acce ptan ce of fiel db us in pro ess a to mation. It is t e en ablin t chnol ogy for fieldb us in haza rdo s areas, be cause it satisfies the

nee for lon trunk cables while at the same time allowing a larg e numbe of de- vices per segment. Th e des red cost reduction in engi nee in g, installation, chec k-o t an d com missioning a e a hieved. Figure 3: High- Power Trunk fo r any hazardo area Se gme t Protectors provide short-circuit protection and non-ince ndive energy limitation (Ex nL). . Fi eldBarriers provide intri nsic safety (Ex i). ww w.peppe l- fuchs. com 5/9 2008-
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DART – Dynamic Arc Reco gnition and Termination Intri sically s fe Fiel db us i Ha zardous A eas 7- 28 EDM TD 548_ ENG 211701 The sam to pology

can b us ed for al l areas: non-h za rdo s, Zone 2 a nd i trinsi cal y safe Zone 1, 0 a ppl ications. Attri utes en able by the HPTC are: Highest possible ove all ca ble l th a at the s me ti me l rgest numbe of fi eld devices per se gme t Live wor o fi eld devic s all wed without hot work permit 4 times l ss v luable cabinet space re- qui re d with st and pow sup lies com pared to FISC O compliant s pplies Easiest vali dation of int insi c saf ty once pe r s with no c lc ulation re ire Mix and match of FISCO and Entity co m- pliant devices on one segment Red cy of the pow su ppli s Inte grat

ed ph ysical lay r di agnostics for long-t rm mo nitoring DART – Dynamic Arc Recognition and Termination 6.1 Descri ption Acco rdi ng to I C 60 079-11 [ ]a n ele tric rc uit is considered intrinsically s if it can be guaran- teed that “ele ctrical en ergy within the appa ratus and of inte rc onne cting wir ng e pos d to the potentially e plosiv e atmos he re is rest ri cted to a level below that which can cause i gni tion by either sparking or h eatin g effe cts”. Curre tly intrinsically safe system designs rely primarily on the co ntinuo us limitat on of the available powe r. Dy nam c A Re

cog ion an d T rmi ation (DART) technology eliminates this restricting factor th rough a totally new approach t energy limitation: Whe a spark occurs it ad ually heat s up. It remains non-i cendive duri ng its initial phase rea hin in cendive t erat ures d ri ng the critical phase (Figure 4). DART dete cts the cha act ri stic elect ic b havior of a s k, m re s ificall the sha p curre chan ge di/dt, see Figure 4. DART safely li mits the energy within the first 5…1 mi cro s co nds of a spa k bei ng tecte (Figur e 5), which is during the initial ph ase of the spark, a nd th erefore spa k is extin

uishe be fo re it becomes incen- dive Figure 4: Typic l electric behavior of a spark. Cur- rent, voltage and power show n over time. Figure 5: An electric spark terminated by DA RT before it becomes incendive. Verification of intrinsic safety of DART power su pp lie an d Se en t P ote tor is p ssib e acco rdi ng to existing stan dar s usin g modified testing metho s. These new methods for testing of dynamic ll y acting po r supplies a e c rently b in g introd uc ed to the standard. Valida- tion of intrinsic safety wi ll utilize the same mech anisms currently use to ve rify FISCO a plications.

With DART all HPTC characteristics such as amount of available po wer, re an cy, dia nostics and support of FISCO/E tity devices ma in en ab le Ad tionally the tru k is n intrinsic lly safe allowin mainte na nce along the trunk unde r ation wi th out hot work permit. 6.2 Appraisal DART represents the next, though revolutionary ste fr om the Hig ow er Tr un nc ept. DA fieldb us allow up to 1000 m cable le ngt h and up to 24 devices pe r se gm ent. I mm ary: Intri sically s fe protection of the entire segment i cluding the trunk Support of Po wer supply redundancy Conne ction of any FISCO and

Entit compli ant dev ce, s me as H TC 6/9 ww w.peppe l- fuchs. com 2008- Continuo us A ed Phy ical Laye r di agnostics.
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Intri sically s fe Fiel db us i Ha zar ous A eas Techni cal Co mpa ison Technical Comparison 7.1 General per formance of the intrinsi ally safe fieldb s solutions As a summa ry the following table gives a brief overview of the basic meri ts and dra cks o the four intri sically safe fieldbus solut ons in- troduced i th is paper: Table 1: Gen l Performance Summ ry Entity FISC O (redun nt) High-Power Trunk DART Available Power + + Validation of Explosion

Protection + + + Power Supply Redund ancy *) + + Long term Physical Layer Diagnostics + + Segment Design Mix Cabinet Spac e Requireme t + + Power Supply Initial Cost Trunk Live Working + + * currently not c rtified 7.2 Compariso n based on real-life application requirements As basis for the cas study the following values and limits are taken into con ideration: The ave ag e curre t is de rived f om value foun d in d tas eets of o di ry i str ments such as Rosemo unt 8 00C Flow meter, ABB pressure t ansmitter 265DC and Eme son Temperat ure T ans itter 848T. 7- 28 EDM TD 548_ ENG 211701 IEC

61158-2 defines 9 V as the mi nimum voltage level a inst rume nt nee s fo r pro o er ation. A ddi ng a s fety m in of 10% is us ually demanded by specifica- tions as res rve. This result s in a mini- mum fiel d dev ce voltag e l vel of 10 V. In o der to allow future extensions of one or two instr ments an d to avoid over use of the powe r s lies a c nt rese rv e of 20 % is factored i . Distribution units protect th e trunk from spur sho ts. A short additionally loads the trunk with 20 mA i the event. Distribution units contai n elect onics d cons ume approxi ately 5 mA per unit. An AWG 18 fiel

db us cabl e o erate at a temperat ure o 50C has a re sistor value of 50 ohms per km. Table 2: Basic values for case study calculation Parameter Value Instrume nt average current consum ption 20 mA Minimum avail bl e vol age available to instrument 10 V Current reserve for future exten- sions per segment 20% Power supply load reserve for short-circuit co ndition 20 mA Current cons um ption per wiring interface, where used 5 mA Cable specification AWG 18, 50 /km ww w.peppe l- fuchs. com 7/9 2008-
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Intri sically s fe Fiel db us i Ha zardous A eas The com aris on shown i

T ble 3 ill stra tes the significa nt dif ere ces in a tual avail bl e cabl e length, n er of fi eld instrume nts f r ea ch method described in this paper. Pri arily the voltage level i the const ai nt for the m ximum achievabl ca ble len th, w ile the curre t value is the constraint for the number of field instru- ments that ca n b o ate . Calculation b sis is the voltage level a po wer supply provides under lo ad which is typically 10…2 0 % less than the ma ximum voltage avail- able at no loa . The eff ctiv ely availabl e current describes the current avail ble fo r the f eld in struments.

It is calcul ated by the 20 % current rese rv e, the subtr ction 20 mA shor t circ uit t 5 ltip lied b the num er of distribution units in us e. From the perf orma nce in di cator values listed in Table 3 th e concl sion can be draw n th at the High-Pow er T unk co ncept enabl s the longest cabl e runs w ile at sa me time allo win for satisfactory mb er of fi el d d vices. DA RT how- ever has the potential to b come the altern ative once it has b een gen rally accepte , as it pro- vides a compl tely intrinsi cally safe solut on with the same amo nt of powe r for the same n mb er of d vice s an

d c e le ng th. Table 3: Value calculated for Real-Life appl ication Entity FISCO Performance indicator IIC IIB IIC IIB High-Power Trunk DART Maximum outp ut vol age Output voltage under load 10.9 V 10.6 V 18,6 5 V 17 V 14 V 12.4 V 14.8 V 13.1 V 30 V 28.5 V 24 V 22 V Maximum output current Effectively available current 100 mA 55 m 35 0 m 55 m 120 mA 66 mA 265 m 177 mA 500 mA 360 m 360 m 248 mA Real -l ife trunk l ng th (theoretic trunk length) 180 m (1900 m) 700 m (1900 m) 570 m (1000 m) 290 m (1900 m) 670 m (1900 m) 670 m (1000 m) Real-life spur length (theoretic spur length) 30 m (120 m 60 m

(120 m 60 m (60 m) 60 m (60 m) 100 m (120 m 100 m (120 m) Max. Number of field devices 2 8 4 8 12 12 8/9 ww w.peppe l- fuchs. com 2008- 7- 28 EDM TD 548_ ENG 211701
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Intri sically s fe Fiel db us i Ha zardous A eas Concl sion Conclusion Begi nnin with a historic re view how the i trinsi cally saf technology developed and h w the High-Pow er T un k has le ad to the wide option of fieldbus te chnology this paper provid es valu- able d cision makin crite ia whe e FIS O and comparable s lutions such as the HPT have their merits and drawbacks Of all existing tech niques th e Hi

gh-Po Trun k co nce t off rs most ben fits to users wh en a fieldb us inst allation implements intrinsically saf field device. For the future, DART with a total power rating of watts per s gment offers more than 4 times the amount of in trinsically s en ergy tha with FISCO and 3 times more field devic s. This im- provem ent wil have the biggest influen on the success of fieldb us com are to any other previ- ous improve ents. This time we ca n reall speak about the “next generation of int insic safety. 7- 28 EDM TD 548_ ENG 211701 Figur 4 D RT the f tur of intrinsic s fe fieldbus te chni que As

a logi cal progression to t e High-Po er Trunk Concept, DART meets th e demand fo r an intrinsi- cally safety trunk line wh ile providin higher levels of avail ble pow r. It is the ne xt mil stone and the lo gic l next cha ter in the stor y of “In- trinsically Saf F eld us in the Haz ous Are References [1] PTB re port PTB- W-53 : „Investigations into Int insic Safety of fiel d bus systems”, Physikalisch Technis he B ndes nstalt, Braunschweig August 1994 [2] FF- 816: FOUNDATION TM Specification „31.25 kbit/s Physical Layer Profile”, Fieldbu Foundation Revision 1.0, May 1996 [3] IEC 60 079-27:

Inte rnation l stand p- pa ratus for ex plosive g s atmosphe res FISCO/FNICO”, Intern ion l E ec tr otec h- nical Commis ion, First Edit ion 2005-04 [4] IEC 61158-2: International s andard „Di i- tal d ta comm uni ation fo r meas ureme t and co ntrol Fieldbus for use in in dust ria control systems Part 2: Physical Layer specification , Intern ion l E ec tr otec h- nical Commis ion, Fourth e ition 2 007 -12 [5] IEC 60 079–11: Int ational stand plosiv e atmos he res – Eq ui pme t prote tion by i trins c safety “i” “,International Elect otech ical Commissio , Fifth e ition 20 06- 7 [6] 5’th PC IC

Euro pe: „DART – T e Ne w Di mension of Int insic Safety”, Pet olium & Chemical Industry Committee, Weimar Germa y June 20 08- ww w.peppe l- fuchs. com 9/9 2008-
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Subject to reaso able modifica tions due to technical advances Copyright PE PPE RL+FUCHS • Pri ted in Ger any • Part No: 11701 07/2008 07/2008