IEC 60079 27 Edition 2 0 2008 01 INTERNATIONAL STANDARD NORME INTERNATIONALE Explosive atmospheres – Part 27 Fieldbus intrinsically safe concept (FISCO) Atmosphères explosives – Partie 27 Concept de r[.]
Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60079-0,
IEC 60079-11 and IEC 60079-15 as well as the following apply
NOTE Additional definitions applicable to explosive atmospheres can be found in IEV 60050-426.
Abbreviations
FISCO Fieldbus Intrinsically Safe Concept
FNICO Fieldbus Non-Incendive Concept
General
Apparatus shall be constructed in accordance with IEC 60079-11 except as modified by this standard
The apparatus documentation shall confirm that each apparatus is suitable for use in a FISCO system in accordance with this standard.
FISCO power supplies
General
The power supply shall either be resistive limited or have a trapezoidal or rectangular output characteristic The maximum output voltage, U o , shall be not greater than 17,5 V nor less than
14 V under the conditions specified in IEC 60079-11 for the respective level of protection
The maximum unprotected internal capacitance Ci and inductance Li shall be not greater than
The output from the power supply may be connected to earth
No specification of the internal parameters Li and Ci or the maximum external parameters Lo and Co is required on the certificate or label
The determination of power supply output parameters shall take into account the possible opening, shorting and earthing of field wiring connected to the field terminals of the apparatus.
Additional requirements of “ia” and “ib” FISCO power supplies
The maximum output current Io for any “ia” or “ib” FISCO power supply shall be determined in accordance with IEC 60079-11 but shall not exceed 380 mA For rectangular supplies,
Table 1 may be used for assessment
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Table 1 – Assessment of maximum output current for use with “ia” and “ib” FISCO rectangular supplies
Permissible current, for IIC (includes 1,5 safety factor) mA
Permissible current, for IIB (includes 1,5 safety factor) mA
17 81 240 17,5 75 213 NOTE The two largest current values for IIB are derived from 5,32 W
The maximum output power P o shall not exceed 5,32 W.
Additional requirements of “ic” FISCO power supplies
The maximum output current I o for an “ic” FISCO power supply shall be determined in accordance with IEC 60079-11 For “ic” FISCO rectangular supplies, Table 2 may be used for assessment
Table 2 – Assessment of maximum output current for use with “ic” FISCO rectangular supplies
Permissible current, for IIC mA
Permissible current, for IIB mA
NOTE The maximum output power P o from “ic” FISCO power supplies is not restricted to 5,32 W.
FISCO field devices
General
These requirements apply to apparatus other than the power supply terminators and simple apparatus connected to the intrinsically safe bus whether installed inside or outside the hazardous area
In addition to the relevant sections of IEC 60079-11, hand held terminals shall comply with the requirements for field terminals
Field devices must meet specific requirements, including a minimum input voltage of \$U_i = 17.5 \, V\$, a maximum unprotected internal capacitance of \$C_i \leq 5 \, nF\$, and bus terminals that are isolated from earth as per IEC 60079-11 Additionally, the bus terminals of separately powered field devices must be galvanically isolated from other power sources in accordance with IEC 60079-11 to ensure passive operation and prevent multiple earthing of the bus.
Licensed to MECON Limited for internal use in Ranchi/Bangalore, this document outlines that under normal or fault conditions as per IEC 60079-11, the bus terminals must remain passive, ensuring they do not act as an energy source for the system, except for a leakage current not exceeding 50 µA Additionally, field devices must be assigned an appropriate level of protection and be compatible with the specified apparatus group.
IIC in accordance with IEC 60079-11; g) field devices intended to be installed within the hazardous area shall be temperature classified in accordance with IEC 60079-11.
Additional requirements of “ia” and “ib” FISCO field devices
The FISCO field devices must meet specific additional requirements: they should have minimum input parameters of \$I_i = 380 \, \text{mA}\$ and \$P_i = 5.32 \, \text{W}\$, and an internal inductance \$L_i\$ that does not exceed \$10 \, \mu\text{H}\$.
Additional requirement of “ic” FISCO field devices
The additional requirement of “ic” FISCO field devices is that they shall have an internal inductance L i not greater than 20 àH.
Terminator
The system requires line terminators that consist of a resistor-capacitor combination, which must present an equivalent circuit at its terminals of a minimum resistor value of 90 Ω in series with a maximum capacitor value of 2.2 àF, including tolerances.
NOTE 1 IEC 61158-2 specifies the component values necessary for operational reasons
The terminator shall a) be allocated a level of protection and be suitable for apparatus group IIC; b) have an input voltage parameter U i not less than 17,5 V;
If the capacitive components are deemed capable of failing and causing a short circuit, the necessary power rating for the resistors is 5.1 W Additionally, the temperature class must be established based on this power dissipation.
To ensure safety in hazardous areas, devices must be isolated from earth as per IEC 60079-11 standards Additionally, the maximum unprotected internal inductance (L_i) should not exceed 10 µH Furthermore, any terminators installed within these hazardous zones must be temperature classified according to IEC 60079-11.
The terminators may be incorporated within field devices or power supplies
NOTE 3 For safety assessment purposes, the effective capacitance (C i ) of the terminator is considered not to affect the intrinsic safety of the system.
Simple apparatus
Simple apparatus used in intrinsically safe systems must comply with IEC 60079-11 standards It is essential to know the capacitance and inductance of the simple apparatus to evaluate the system requirements outlined in section 5.1 Additionally, the total inductance and capacitance of each simple apparatus connected to a FISCO system should not exceed specified limits.
When classifying the temperature of simple apparatus in an “ia” or “ib” system, it is crucial to consider that the maximum available power can reach up to 5.32 W In contrast, the temperature classification for an “ic” system is determined during normal operation.
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Marking
All apparatus, except for simple devices, must be labeled with the term "FISCO" along with a description of its function, such as power supply, field device, or terminator Furthermore, each apparatus should be marked in compliance with relevant standards.
IEC 60079-11, except where modified by this standard For example, the manufacturer’s name and address shall still be marked
When apparatus is dual marked for use in both FISCO and conventional intrinsically safe systems, it is essential to clearly distinguish between the FISCO marking and the marking for the conventional intrinsically safe system.
For FISCO power supplies, output parameters U o , I o , C o , L o , P o and L o /R o need not be marked For FISCO field devices or terminators, input and internal parameters U i , I i , C i , L i , P i and L i /R i need not be marked.
Examples of marking
Serial No: 012345 d) Dual marked field device
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General
A system is usually of the form illustrated in Annex A
The cable specifications for the system must adhere to specific parameters: a loop resistance ranging from 15 Ω/km to 150 Ω/km, a loop inductance between 0.4 mH/km and 1 mH/km, and a capacitance of 45 nF/km to 200 nF/km Additionally, the maximum length for each spur cable is set at 60 m for both IIC and IIB classifications, while the total length of each trunk cable, including all spur lengths, must not exceed 1 km in IIC.
When cable, which complies with this standard, is used, no further consideration of cable parameters is necessary
The installation and construction requirements for individual cables and multicore cables carrying multiple IS circuits are outlined in IEC 60079-14 Additionally, Annex C of this standard provides guidance on determining cable parameters.
A system is deemed adequately safe when it includes one power source, up to 32 field devices, and a maximum of two terminators, all adhering to the specified standards, along with a compliant cable.
The system will be assigned a protection level of “ia”, “ib”, or “ic”, based on the least stringent protection level of the equipment utilized within the system It is essential for the safety documentation to reflect the designated protection level accurately.
Different sub-systems within a system can have varying levels of protection, which should be justified through assessment and documented accordingly For instance, a spur classified as "ia" can be derived from an "ib" trunk by incorporating a properly certified interface.
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The terminators must be positioned at the ends of the trunk, with the power supply located within 60 meters of one end If the power supply is connected through a spur, the length of that spur is also limited to 60 meters.
The standard limits the number of field devices that can be connected to a spur to a maximum of 32 due to operational constraints.
Connection facilities and switches can be integrated into a system without altering the safety assessment Additionally, simple apparatus that meets IEC 60079-11 standards can be connected to a FISCO system, provided that the total inductance does not exceed 10 µH and the total capacitance remains under 5 nF Furthermore, the combined total of simple apparatus and field devices must not surpass 32 units.
Safety documentation can be streamlined into a list of equipment along with the corresponding apparatus documentation It is essential that this documentation clearly specifies the protection level for each component of the system.
The apparatus group of the power supply determines the apparatus group of the system
The temperature classification for each piece of equipment must be established and documented Additionally, it is essential to verify that the maximum allowable ambient temperature for each apparatus is appropriate for its designated location.
Additional requirements of “ic” FISCO systems
Apparatus designed and approved to the FNICO requirements of the first edition of this standard may be used in an “ic” FISCO system
Field devices, terminators and other ancillaries complying with the requirements of intrinsic safety but not as FISCO apparatus in accordance with this standard may be used with a
In a FISCO system, the power supply must have input parameters of \$U_i\$ no less than 17.5 V, along with internal parameters \$L_i\$ and \$C_i\$ that do not exceed 20 µH and 5 nF, respectively.
Apparatus that is not certified as FISCO but is built to meet the IEC 60079-15 standards for energy-limited “nL” devices can be utilized if it has input parameters of Ui at least 17.5 V and internal parameters of Li and Ci not exceeding 20 µH.
5 nF respectively, may be used in an “ic” FISCO system
In an “ic” FISCO system, it is essential to indicate the use of FNICO, intrinsically safe, or energy-limited apparatus at the installation point This should be clearly marked with a plant label designated as “ic.”
FISCO system” is an acceptable way of satisfying this requirement
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IEC 60050-426, International Electrotechnical Vocabulary (IEV) – Chapter 426: Electrical apparatus for explosive atmospheres
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4.2.2 Exigences supplộmentaires des alimentations FISCO ôiaằ et ôibằ 19
4.2.3 Exigences supplémentaires pour la source d'alimentation FISCO ôicằ 19
4.3.2 Exigences supplộmentaires des dispositifs de terrain FISCO ôiaằ et ôibằ 20
4.3.3 Exigences supplộmentaires des dispositifs de terrain FISCO ôicằ 20
5.2 Exigences supplộmentaires pour la source d'alimentation FISCO ôicằ 23
Tableau 1 – Evaluation du courant maximal de sortie approprié aux alimentations à caractộristique de sortie rectangulaire FISCO avec ôiaằ et ôibằ 19
Tableau 2 – Evaluation du courant maximal de sortie approprié aux alimentations à caractộristique de sortie rectangulaire FISCO ôicằ 19
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Partie 27: Concept de réseau de terrain de sécurité intrinsèque (FISCO)
The International Electrotechnical Commission (IEC) is a global standards organization comprising national electrotechnical committees Its primary goal is to promote international cooperation on standardization in the fields of electricity and electronics To achieve this, the IEC publishes international standards, technical specifications, technical reports, publicly accessible specifications (PAS), and guides, collectively referred to as "IEC Publications." The development of these publications is entrusted to study committees, which allow participation from any interested national committee Additionally, international, governmental, and non-governmental organizations collaborate with the IEC in its work The IEC also works closely with the International Organization for Standardization (ISO) under an agreement established between the two organizations.
Official decisions or agreements of the IEC on technical matters aim to establish an international consensus on the topics under consideration, as each study committee includes representatives from the relevant national IEC committees.
The IEC publications are issued as international recommendations and are approved by the national committees of the IEC The IEC makes every reasonable effort to ensure the technical accuracy of its publications; however, it cannot be held responsible for any misuse or misinterpretation by end users.
To promote international consistency, the national committees of the IEC commit to transparently applying IEC publications in their national and regional documents as much as possible Any discrepancies between IEC publications and corresponding national or regional publications must be clearly stated in the latter.
5) La CEI n’a prévu aucune procédure de marquage valant indication d’approbation et n'engage pas sa responsabilité pour les équipements déclarés conformes à une de ses Publications
6) Tous les utilisateurs doivent s'assurer qu'ils sont en possession de la dernière édition de cette publication
The IEC and its administrators, employees, agents, including external experts and members of its study committees and national committees, shall not be held liable for any injuries, damages, or any other type of loss, whether direct or indirect This includes any costs or expenses, such as legal fees, arising from the publication or use of this IEC Publication or any other IEC Publication, or from the credit attributed to it.
8) L'attention est attirée sur les références normatives citées dans cette publication L'utilisation de publications référencées est obligatoire pour une application correcte de la présente publication
It is important to note that some elements of this IEC publication may be subject to intellectual property rights or similar rights The IEC cannot be held responsible for failing to identify such property rights or for not indicating their existence.
La Norme Internationale CEI 60079-27 a été établie par le sous-comité 31G: Matériels à sécurité intrinsèque, du comité d’études 31 de la CEI: Equipements pour atmosphères explosives
Cette deuxième édition annule et remplace la première édition publiée en 2005 Elle constitue une révision technique
Les modifications principales par rapport à l’édition précédente sont que dans cette norme les exigences FNICO sont remplacộes par les exigences d’un systốme FISCO ôicằ
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Le texte de la présente norme est issu des documents suivants:
Les rapports de vote indiqués dans le tableau ci-dessus donnent toute information sur le vote ayant abouti à l'approbation de cette norme
Cette publication a été rédigée selon les Directives ISO/CEI, Partie 2
Une liste de toutes les parties de la CEI 60079, sous le titre général Atmosphères explosives, est disponible sur le site web de la CEI
The committee has decided that the content of this publication will not be modified until the date of the maintenance results indicated on the IEC website At that time, the publication will be updated accordingly.
• remplacée par une édition révisée, ou
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Partie 27: Concept de réseau de terrain de sécurité intrinsèque (FISCO)
This section of IEC 60079 provides details on equipment, systems, and installation methods for use in accordance with the Fieldbus Intrinsic Safety Concept (FISCO) It is based on the principles of Manchester coded fieldbus systems designed according to IEC 61158-2, which is the standard for the physical layer of fieldbus installations.
The construction and installation requirements for FISCO equipment and systems are defined by IEC 60079-11, IEC 60079-14, and IEC 60079-25, except where modified by this standard Each component of the fieldbus system may be protected by one of the explosion protection methods listed in IEC 60079-0, suitable for the intended usage area In these cases, the requirements of this standard apply only to the part of the equipment directly connected to the intrinsic safety line or segment.
Certification according to FISCO requirements does not prevent equipment from also being conventionally certified and marked according to IEC 60079-11, allowing for their use in other systems.
Materials certified prior to the publication of this standard, while not necessarily compliant with its electrical parameters, may be labeled as "Adapted to FISCO systems." These materials can be accepted into the FISCO system if a comparison of the electrical parameters \(U_o\), \(I_o\), and \(P_o\) with \(U_i\), \(I_i\), and \(P_i\) demonstrates compatibility with the rest of the system, provided that all other requirements of the current standard are met.
NOTE 2 Un système typique est illustré à l’Annexe A
FISCO systems are primarily designed for use in Zone 1 and Zone 2 environments However, with specific authorization outlined in the documentation, they can also be utilized in Zone 0.
Termes et définitions
Pour les besoins du présent document, les termes et définitions de la CEI 60079-0, de la
CEI 60079-11 et de la CEI 60079-15 ainsi que les suivants s’appliquent
NOTE Des définitions supplémentaires applicables aux atmosphères explosives se trouvent dans le
Abréviations
FISCO concept de réseau de terrain de sécurité intrinsèque
FNICO concept de réseau de terrain non incendiaire
Généralités
Le matériel doit être construit en conformité avec la CEI 60079-11 à l’exception de ce qui est modifié par cette norme
La documentation du matériel doit confirmer que chaque matériel est adapté pour une utilisation dans un système FISCO en conformité avec cette norme.
Sources d'alimentation FISCO
Généralités
The power supply must either have limited resistance or exhibit a rectangular or trapezoidal output characteristic The maximum output voltage, U₀, should not exceed 17.5 V or fall below 14 V, in accordance with the conditions specified in IEC 60079-11 for the respective level of protection.
La capacité interne non protégée maximale C i et l’inductance L i ne doivent pas dépasser, respectivement, 5 nF et 10 àH
Aucune spécification des paramètres internes, L i et C i , ou des paramètres externes maximaux, L o et C o , n'est exigée dans le certificat ou le marquage
La sortie de l’alimentation peut être connectée à la terre
La détermination des paramètres de sortie de l’alimentation doit prendre en compte la possibilité d’ouverture, de court-circuit et de mise à la terre du câblage aux bornes du matériel
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Exigences supplémentaires pour la source d'alimentation FISCO ôicằ
Le courant maximal de sortie I o pour tout type de source d'alimentation FISCO ôiaằ ou ôibằ doit être déterminé en conformité avec la CEI 60079-11 mais ne doit pas dépasser 380 mA
Pour les alimentations rectangulaires, le Tableau 1 peut être utilisé pour l'évaluation
Tableau 1 – Evaluation du courant maximal de sortie approprié aux alimentations à caractộristique de sortie rectangulaire FISCO avec ôiaằ et ôibằ
Courant autorisé pour IIC (coefficient de sécurité 1,5 inclus) mA
Courant autorisé pour IIB (coefficient de sécurité 1,5 inclus) mA
17 81 240 17,5 75 213 NOTE Les deux valeurs supérieures pour IIB sont déduites de 5,32 W
La puissance de sortie maximale P o ne doit pas dépasser 5,32 W
4.2.3 Exigences supplộmentaires pour la source d'alimentation FISCO ôicằ
Le courant maximal de sortie I o pour une alimentation FISCO ôicằ doit ờtre dộterminộ conformộment à la CEI 60079-11 Pour les alimentations rectangulaires FISCO ôicằ, le
Tableau 2 peut être utilisé pour l’évaluation
Tableau 2 – Evaluation du courant maximal de sortie approprié aux alimentations à caractộristique de sortie rectangulaire FISCO ôicằ
Courant autorisé, pour IIC mA
Courant autorisé, pour IIB mA
NOTE La puissance de sortie maximale P o des alimentations FISCO ôicằ n’est pas limitộe à 5,32 W.
Dispositifs de terrain FISCO
Généralités
These requirements pertain to equipment other than the power supply for line ends and simple devices connected to the intrinsic safety bus, whether installed inside or outside of hazardous locations.
En plus des sections applicables de la CEI 60079-11, les raccordements manuels doivent satisfaire aux exigences des raccordements de terrain
The requirements are as follows: a) field devices must have a minimum input voltage of U i, 5 V; b) the maximum unprotected internal capacitance Ci of each network device must not exceed 5 nF; c) the connection terminals must be isolated from the ground in accordance with the specified standards.
Licensed to MECON Limited for internal use in Ranchi and Bangalore, supplied by Book Supply Bureau The connection terminals of separately powered field devices must be galvanically isolated from other power sources in accordance with the regulations.
CEI 60079-11 ensures that terminals remain passive and prevents multiple grounding connections during normal operation or fault conditions as defined in the standard.
The connection terminals must remain passive, meaning they should not serve as a power source for the system, except for a leakage current not exceeding 50 µA Additionally, field devices must have an appropriate level of protection and be suitable for equipment classified as group IIC, in accordance with IEC 60079-11 Furthermore, field devices intended for installation within hazardous locations must possess a temperature class compliant with IEC 60079-11.
Exigences supplộmentaires des dispositifs de terrain FISCO ôiaằ et ôibằ
Les exigences supplộmentaires des dispositifs de terrain FISCO ôiaằ et ôibằ sont les suivantes: a) les dispositifs de terrain doivent avoir des paramètres d’entrée minimaux de I i 80 mA et
P i = 5,32 W; b) les dispositifs de terrain doivent avoir une inductance interne L i ne dộpassant pas 10 àH.
Exigences supplộmentaires des dispositifs de terrain FISCO ôicằ
L’exigence supplộmentaire des dispositifs de terrain FISCO ôicằ est qu’ils doivent avoir une inductance interne L i ne dépassant pas 20 μH.
Bout de ligne
The required line ends by the system must include a combination of resistance and capacitor, resulting in an equivalent circuit at the line end with a minimum resistance value of 90 Ω in series with a maximum capacitance value of 2.2 µF.
NOTE 1 La CEI 61158-2 spécifie les valeurs des composants nécessaires pour des raisons de fonctionnement.
Le bout de ligne doit a) avoir un niveau de protection et être adapté au matériel du groupe IIC; b) avoir un paramètre de tension d’entrée U i non inférieur à 17,5 V;
When considering that capacitive components may fail and cause a short circuit, the required power rating for the resistor is 5.1 W, and the temperature class should be determined with a power dissipation of 3.4 W Additionally, it must be isolated from the ground in accordance with IEC 60079-11, have a maximum unprotected internal inductance L not exceeding 10 µH, and the line ends intended for installation in hazardous locations must be temperature classified according to IEC 60079-11.
Les bouts de ligne peuvent être incorporés dans les dispositifs de terrain ou dans les sources d'alimentation
NOTE 3 Pour les besoins d’évaluation de la sécurité, la capacité effective (C i ) du bout de ligne est considérée ne pas affecter la sécurité intrinsèque du système.
Matériel simple
The requirement for simple equipment used in an intrinsic safety system is that it must comply with IEC 60079-11 To assess the system against the requirements of section 5.1, the capacitance and inductance of the simple equipment must be known.
Licensed to MECON Limited in Ranchi/Bangalore for internal use only, supplied by Book Supply Bureau The total inductance of each simple device connected to a FISCO system must not exceed 10 μH, and the total capacitance must not exceed 5 nF.
It is essential to carefully classify the temperature for simple equipment in an ô‘iaằ or ô icằ system, where the maximum available power can reach 5.32 W The temperature classification of an ôicằ system is conducted under normal operating conditions.
Marquage
Every piece of equipment, except for simple materials, must be labeled with the "FISCO" designation along with an indication of its function, such as the power source, field device, or endpoint Additionally, all equipment must be marked in accordance with the relevant standards.
CEI 60079-11, sauf si cela est modifié par la présente norme Par exemple, il faut toujours que le nom et l’adresse du fabricant apparaissent
When equipment features dual marking for use in both a FISCO system and a conventional intrinsic safety system, it is essential to take precautions to distinguish the FISCO marking from the marking for the intrinsic safety system.
Pour les sources d’alimentation FISCO, les paramètres de sortie U o , I o , C o , L o , P o et L o /R o ne nécessitent pas d’être marqués Pour les dispositifs de réseau de terrain ou bouts de ligne
FISCO, les paramètres internes et d’entrée U i , I i , C i , L i , P i et L i /R i ne nécessitent pas d’être marqués.
Exemples de marquage
N° de série: 014321 b) Dispositif de terrain
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N° de série: 012345 d) Marquage double de dispositif de terrain
Généralités
Un système est généralement de la forme de celui représenté à l’Annexe A
The cable used in the system must meet specific parameters: a) a loop resistance (\$R_c\$) ranging from 15 Ω/km to 150 Ω/km; b) a loop inductance (\$L_c\$) between 0.4 mH/km and 1 mH/km; c) a capacitance (\$C_c\$) of 45 nF/km to 200 nF/km; d) a maximum length of each cable segment of 60 m for IIC and IIB; e) a maximum total cable length, including all segments, of 1 km for IIC and 5 km for IIB.
Lorsque le câble utilisé satisfait à cette spécification, aucune autre exigence relative aux paramètres du câble n'est nécessaire
The installation and construction requirements for individual and multi-strand cables carrying more than one IS circuit are outlined in IEC 60079-14 Additionally, Annex C of this standard serves as a guide for determining cable parameters.
A system is deemed to have adequate safety when it includes a) a power source, b) up to 32 field devices, and c) up to two line ends, all compliant with the specified standards, and connected with a cable that meets the aforementioned specifications.
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The system must be assigned a protection level (ôiaằ, ôibằ, or ôicằ) determined by the least expensive protection level of the equipment used in the system It is essential to document the assigned protection level in the security documentation.
Subsystems within the system may have varying levels of protection, justified by assessment and documented accordingly For instance, a segment can be created from a line by inserting an appropriate certified interface.
Line ends must be positioned at the extremities of the line The power source should be located within 60 meters of one end of the line When the power is connected through a segment, that segment must be limited to a length of 60 meters.
The number of field devices that can be connected to a segment is restricted by operational constraints and the requirements of the standard, which limits the maximum number of field devices in a system to 32.
Des installations de connexions et/ou des interrupteurs peuvent être ajoutés à un système sans en modifier la sécurité D’autres types de matériels simples conformes à la
CEI 60079-11 devices can be connected to a FISCO system, provided that the inductance and total capacitance of each simple device do not exceed 10 µH and 5 nF, respectively Additionally, the total number of simple devices plus field devices must not exceed 32.
Security documentation can be streamlined into a list of equipment, accompanied by the relevant documentation for each piece of hardware used It is essential that the documentation clearly identifies the protection level of each component within the system.
Le groupe de matériel de la source d'alimentation détermine le groupe de matériel du système
The temperature classification for each equipment component must be established and documented It is also essential to verify that the maximum allowable ambient temperature for each part is suitable for its location.
Exigences supplộmentaires pour la source d'alimentation FISCO ôicằ
Le matộriel conỗu et approuvộ par les exigences FNICO de la premiốre ộdition de cette norme peut ờtre utilisộ dans un systốme FISCO ôicằ
Field network devices, including line ends and other auxiliary equipment that meet intrinsic safety requirements but do not qualify as FISCO equipment according to the standard, can be utilized with a FISCO power source within a system.
FISCO ôicằ à condition d’avoir des paramốtres d’entrộe de U i qui ne soient pas infộrieurs à
17,5 V et des paramốtres internes de L i et C i qui ne dộpassent pas, respectivement, 20 àH et
Similarly, equipment that is not approved as FISCO but is constructed in accordance with the requirements for limited power devices (LPD) of IEC 60079-15, with input parameters of U i not less than 17.5 V and internal parameters of L i and C i not exceeding 20 µH and 5 nF, respectively, can be utilized in a system.
When using FNICO intrinsic safety equipment or limited power devices in a FISCO system, it is essential to indicate this at the installation point of the equipment A display indicating the FISCO system is an effective way to meet this requirement.
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La Figure A.1 représente un système typique
1 Bout de ligne 5 Dispositifs de terrain
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CEI 60050-426, Vocabulaire Electrotechnique International (VEI) – Chapitre 426: Matériel électrique pour atmosphères explosives
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