Communication systems for meters - Part 2: Wired M-Bus communication

This draft European standard is applicable to the physical and link layer parameters of baseband communication over twisted pair (M Bus) for meter communication systems. It is especially applicable to thermal energy meters, heat cost allocators, water meters and gas meters.
NOTE    It is usable also for other meters (like electricity meters) and for sensors and actuators. For generic descriptions concerning communication systems for meters and remote reading of meters see EN 13757-1.

Kommunikationssysteme für Zähler - Teil 2: Drahtgebundene M-Bus-Kommunikation

Systèmes de communication pour compteurs - Partie 2 : Communication M-Bus filaire

La présente Norme européenne est applicable aux paramètres de la couche physique et de liaison de la communication en bande de base sur paire torsadée (M-Bus) pour les systèmes de communication des compteurs. Elle s'applique tout particulièrement aux compteurs d'énergie thermique, aux répartiteurs de frais de chauffage, aux compteurs d'eau et aux compteurs de gaz.
NOTE   Elle est également applicable à d'autres compteurs (tels que les compteurs électriques) ainsi qu'à d'autres capteurs et organes de commande. Pour les descriptions génériques concernant les systèmes de communication et de télérelevé de compteurs, voir l'EN 13757-1.

Komunikacijski sistemi za števce - 2. del: Žične komunikacije po M-vodilu

Ta osnutek evropskega standarda se uporablja za parametre fizične in povezovalne plasti komunikacije v osnovnem pasu prek sukane parice (M-vodilo) za komunikacijske sisteme za merilnike. Uporablja se zlasti za merilnike toplotne energije, delilnike stroškov, merilnike vode in merilnike plina.
OPOMBA:    Lahko se uporablja tudi za druge merilnike (npr. merilnike električne energije) ter za tipala in pogone. Za generične opise v zvezi s komunikacijskimi sistemi za merilnike in oddaljeno odbiranje merilnikov glej standard EN 13757-1.

General Information

Status
Published
Publication Date
03-Apr-2018
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
04-Apr-2018
Completion Date
04-Apr-2018

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.0YRGLOXKommunikationssysteme für Zähler - Teil 2: Drahtgebundene M-Bus-KommunikationSystèmes de communication pour compteurs - Partie 2 : Communication M-Bus filaireCommunication systems for meters - Part 2: Wired M-Bus communication35.100.10Physical layer33.200Daljinsko krmiljenje, daljinske meritve (telemetrija)Telecontrol. TelemeteringICS:Ta slovenski standard je istoveten z:EN 13757-2:2018SIST EN 13757-2:2018en,fr,de01-junij-2018SIST EN 13757-2:2018SLOVENSKI

STANDARDSIST EN 13757-2:20051DGRPHãþD
SIST EN 13757-2:2018
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 13757-2
April
t r s z ICS
u uä t r râ
u wä s r rä s râ
u wä t v rä { {â
{ sä s v rä w r Supersedes EN
s u y w yæ tã t r r vEnglish Version
Communication systems for meters æ Part
tã Wired MæBus communication Systèmes de communication pour compteurs æ Partie
t ã Communication MæBus filaire
Kommunikationssysteme für Zähler æ Teil

tã Drahtgebundene MæBusæKommunikation This European Standard was approved by CEN on

z February
t r s zä

egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä

translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä

CEN members are the national standards bodies of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Serbiaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey and United Kingdomä

EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre:
Rue de la Science 23,
B-1040 Brussels

t r s z CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä EN

s u y w yæ tã t r s z ESIST EN 13757-2:2018
EN 13757-2:2018 (E) 2 Contents Page

European foreword ....................................................................................................................................................... 3 Introduction .................................................................................................................................................................... 5 1 Scope .................................................................................................................................................................... 5 2 Normative references .................................................................................................................................... 6 3 Terms and definitions ................................................................................................................................... 6 4 Physical layer specifications ....................................................................................................................... 6 4.1 General ................................................................................................................................................................ 6 4.2 Electrical requirements slave ..................................................................................................................... 7 4.3 Electrical requirements master ................................................................................................................. 9 4.4 Electrical requirements mini-master ................................................................................................... 12 4.5 Repeaters ........................................................................................................................................................ 12 4.6 Burst and surge requirements ................................................................................................................ 13 5 Link Layer (master and slave) ................................................................................................................. 13 5.1 General ............................................................................................................................................................. 13 5.2 Baud rate ......................................................................................................................................................... 13 5.3 Bit position ..................................................................................................................................................... 14 5.4 Byte format ..................................................................................................................................................... 15 5.5 Block format ................................................................................................................................................... 15 5.6 Datagram abort on collision ..................................................................................................................... 15 5.7 Datagram description ................................................................................................................................. 16 6 Tables and figures ........................................................................................................................................ 18 Annex A (informative)

Schematic implementation of slave ..................................................................... 23 Annex B (informative)

Protection against mains voltages ......................................................................... 24 Annex C (informative)

Slave powering options ............................................................................................. 25 Annex D (informative)

Slave collision detect ................................................................................................. 26 Annex E (informative)

Wire installation .......................................................................................................... 27 E.1 General ............................................................................................................................................................. 27 E.2 Type A: small in house installation ........................................................................................................ 27 E.3 Type B: large in house installation ........................................................................................................ 27 E.4 Type C: small wide area net ...................................................................................................................... 27 E.5 Type D: large wide area net ...................................................................................................................... 28 E.6 Type E: mini installation (meter cluster) ............................................................................................ 28 Annex F (informative)

Protocol examples ...................................................................................................... 29 F.1 Startup .............................................................................................................................................................. 29 F.2 Slave (meter) readout ................................................................................................................................ 29 Bibliography ................................................................................................................................................................. 30 SIST EN 13757-2:2018

EN 13757-2:2018 (E) 3 European foreword This document (EN 13757-2:2018) has been prepared by Technical Committee CEN/TC 294 “Communication systems for meters”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2018, and conflicting national standards shall be withdrawn at the latest by October 2018. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 13757-2:2004. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. The following significant technical changes have been incorporated in the new edition of this European Standard: a) more precise definition of collision state under 4.3.3.8; b) modification of application under 5.7.3.4 from “required” to “optional”; c) additional explanations for usage of REQ-SKE under 5.7.3.4; d) addition of new datagram SND-UD2 under 5.7.3.5; e) alignment of Annex D with revised definition of collision state under 4.3.3.8 and f) editorial alignments with other parts of this standard, e.g. replacement of $E5 with ACK. EN 13757 is currently composed with the following parts: — Communication systems for meters — Part 1: Data exchange; — Communication systems for meters — Part 2: Wired M-Bus communication; — Communication systems for meters — Part 3: Application protocols; — Communication systems for meters and remote reading of meters — Part 4: Wireless meter readout (Radio meter reading for operation in SRD bands); — Communication systems for meters — Part 5: Wireless M-Bus relaying; — Communication systems for meters — Part 6: Local Bus; — Communication systems for meters — Part 7: Transport and security services; — CEN/TR 17167, Communication systems for meters — Accompanying TR to EN 13757-2,-3 and -7, Examples and supplementary information. SIST EN 13757-2:2018

EN 13757-2:2018 (E) 4 According to the CEN-CENELEC Internal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. SIST EN 13757-2:2018

EN 13757-2:2018 (E) 5 Introduction This European Standard belongs to the EN 13757 series, which covers communication systems for meters. EN 13757-1 contains generic descriptions and a communication protocol. EN 13757-3 contains detailed description of the application protocols especially the M-Bus Protocol. EN 13757-4 describes wireless communication (often called wireless M-Bus or wM-Bus). EN 13757-5 describes the wireless network used for repeating, relaying and routing for the different modes of EN 13757-4. EN 13757-6 describes a twisted pair local bus for short distance (Lo-Bus). EN 13757-7 describes transport mechanism and security methods for data. The Technical Report CEN/TR 17167 contains informative annexes from EN 13757-2, EN 13757-3 and EN 13757-7. An overview of communication systems for meters is given in EN 13757-1, which also contains further definitions. The Physical and Link Layer parameters for baseband communication over twisted pairs have first been specified in EN 1434-3:1997 (“M-Bus”) for heat meters. This standard is a compatible and interworking update of a part of EN 1434-3:2015 and includes also other measured media (e.g. water, gas, thermal energy, heat cost allocators), the master side of the communication and newer technical developments. It should be noted that EN 1434-3: 2015 covers also other communication techniques. It can be used with various application layers especially the application layer of EN 13757-3. SIST EN 13757-2:2018

EN 13757-2:2018 (E) 6 1 Scope This European Standard is applicable to the physical and link layer parameters of baseband communication over twisted pair (M Bus) for meter communication systems. It is especially applicable to thermal energy meters, heat cost allocators, water meters and gas meters. NOTE

It is usable also for other meters (like electricity meters) and for sensors and actuators. For generic descriptions concerning communication systems for meters and remote reading of meters see EN 13757–1. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 13757-1:2014, Communication systems for meters - Part 1: Data exchange EN 60870-5, (all parts), Telecontrol equipment and systems (IEC 60870-5 series) EN 60870-5-1, Telecontrol equipment and systems - Part 5: Transmission protocols - Section 1: Transmission frame formats EN 60870-5-2:1993, Telecontrol equipment and systems - Part 5: Transmission protocols - Section 2: Link transmission procedures EN 61000-4-4, Electromagnetic compatibility (EMC) - Part 4-4: Testing and measurement techniques - Electrical fast transient/burst immunity test EN 61000-4-5, Electromagnetic compatibility (EMC) - Part 4-5: Testing and measurement techniques - Surge immunity test 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 13757-1:2014 and the following apply. 3.1 unit load one unit load (1 UL) is the maximum mark state current of 1,5 mA 4 Physical layer specifications 4.1 General Figure 1 shows the principal electrical concept of the physical layer: Information from the master to the slaves is transmitted via voltage level changes. A mark state voltage UMark (idle state, typically 36 V) and an space state voltage which is typically 12 V below UMark (but at least 12 V) is used for the data transmission. The high voltage step improves the noise immunity in the master to slave direction. The required minimum voltage supports a stable remote powering of all slaves of a segment. Signalling via a voltage change rather than by absolute voltage levels supports even large voltage drops due to wiring SIST EN 13757-2:2018

EN 13757-2:2018 (E) 7 resistance of the cable installation. All slaves are constant current sinks. Their mark state current of typically 1,0 mA to 1,5 mA can be used for powering the transceiver IC in the slave and optionally also the slave (meter). The active (space state) current transmit of a slave is signalled by an increase of this constant current by (11 to20) mA. Signalling via constant current improves the immunity against induced voltages and is independent on wiring resistance. On the input of each slave transceiver a rectifier bridge makes each slave independent of the wiring polarity and reduces installation errors. Protective resistors in front of each slave transceiver simplify the implementation of overvoltage protection and safeguards, the bus against a semiconductor short circuit in a slave by limiting the current of such a defective slave to 100 mA. Annex A shows the principal function of a slave transceiver. Integrated slave transceivers which include a regulated buffered voltage output for slave (meter) powering, support of battery supply with supply switchover and power down signalling are commercially available.

Key 1 Bus Voltage at Repeater, Master transmits to Slave 2 Current composition of a Slave, Slave transmits to Master t time Figure 1 — Representation of bits on the M-Bus All specification requirements shall be held over the full range of temperature and operating voltage for the responsible system component. 4.2 Electrical requirements slave 4.2.1 Master to slave bus voltages Maximum permanent voltage: - 50 V to 0 V to + 50 V (no damage). Voltage range for meeting all specifications: ± (12 V to 42 V). The Bus voltage at the slave terminals in mark-(quiescent) state of master slave communication (= UMark) shall be ± (21 V to 42 V). SIST EN 13757-2:2018

EN 13757-2:2018 (E) 8 The mark voltage shall be stored by a voltage maximum detector with an asymmetric time constant. The discharge time constant shall be greater than 30 × (charge constant) but less than 1 s. The stored voltage maximum UMark may drop in 50 ms by not more than 0,2 V for all voltages between 12 V and UMark. a) Bus voltage Mark/Space state for master slave communication: 1) Space: UBus < UMark - 8,2 V; 2) Mark: UBus

UMark - 5,7 V; b) maximum space state time: 50 ms; c) maximum space state duty cycle: 0,92. 4.2.2 Slave bus current and multiple unit loads 4.2.2.1 General A slave device may require a maximum mark state current of an integer multiple N (in the range 1 to 4) unit loads. Each terminal device shall be marked with the unit load number N (If > 1) and the device description shall contain a note on the multiple unit loads for this device. 4.2.2.2 Mark state current of a slave device The mark state current IMark shall be

N unit loads. 4.2.2.3 Variation of the mark state current over bus voltage For bus voltages in the range of ± (12 V to 42 V) a voltage variation of 1 V to 15 V shall not change the bus current by more than N × 3 µA/V. 4.2.2.4 Short-term variation of the mark state current At constant bus voltage the bus current shall not change by more than ± 1 % within 10 s. 4.2.2.5 Total variation over allowed temperature and voltage range of slave device The total variation of the mark state current of a slave device shall not vary by more than ± 10 % over the full voltage and temperature range of the slave device. 4.2.2.6 Maximum bus current for any single semiconductor or capacitor defect 1 min after any single semiconductor or capacitor defect the maximum current of any slave device shall be less than 100 mA for any bus voltage

42 V. 4.2.2.7 Slow start For any bus voltage in the range of (0 to ± 42) V the bus current shall be limited to

N × UL. SIST EN 13757-2:2018

EN 13757-2:2018 (E) 9 4.2.2.8 Fast change After any bus voltage change the bus current shall be

N × UL within 1 ms. 4.2.2.9 Space state current The bus current for a slave space state send shall be higher by (11 to 20) mA than in the mark state for all allowed bus voltages: ISpace = IMark + (11 to 20) mA 4.2.2.10 Input capacitance at the slave terminals:

0,5 nF This capacitance shall be measured with a DC bias of (15 to 30) V. 4.2.2.11 Startup delay In case of a bus voltage drop below 12 V for longer than 0,1 s the recovery time after applying an allowed mark state voltage until reaching full communication capabilities shall be less than 3 s. 4.2.2.12 Galvanic Isolation The isolation resistance between any bus terminal and all metal parts accessible without violating seals shall be > 1 M. Excluded are terminals for the connection of other floating or isolated external components. The test voltage is 500 V. For mains operated terminal devices the appropriate safety rules apply. 4.2.2.13 Optional reversible mains protection The slave interface can be equipped with an optional reversible mains protection. This guarantees that even for a prolonged period (test duration: 1 min) the slave interface can withstand mains voltages of 230 V + 10 % and 50 Hz or 60 Hz and that afterwards all specifications are met again. This mains protection function is recommended for all mains operated terminal devices. For possible implementations see Annex B. 4.2.3 Dynamic requirements Any link layer or application layer protocol of up to 38 400 Baud is acceptable if it guarantees that a mark state is reached for at least one bit time at least once in every 11 bit times and not later than after 50 ms. Note that this is applicable for any asynchronous protocol with 5 data bits to 8 data bits (with or without a parity bit) for any baud rate of at least 300 Baud, including a break signal (see 4.3.3.8). It is also applicable for many synchronous protocols with or without bit coding. 4.3 Electrical requirements master 4.3.1 Parameters 4.3.1.1 Max current (IMax) A master for this physical layer is characterized by its maximum current IMaximum. For all bus currents between zero and IMax it shall meet all functional and parametric requirements. For example a maximally loaded segment with up to 250 slaves with 1 UL each (375 mA) plus an allowance for one slave with a short circuit (+ 100 mA) plus the maximum space send current (+ 20 mA) an Imax

0,5 A is required. SIST EN 13757-2:2018

EN 13757-2:2018 (E) 10 4.3.1.2 Max allowable voltage drop (Ur) The maximum voltage drop Ur (>0 V) is defined as the minimum space state voltage minus 12 V. Ur divided by the maximum segment resistance between the master and any terminal device (meter) gives the maximum usable bus current for a given combination of segment resistance and master. 4.3.1.3 Max baud rate (BMax) Another characterization of a master is the maximum baud rate BMax up to which all specifications are met. The minimum baud rate is always 300 Baud. 4.3.1.4 Application description Each master device shall include a description about the required cable and device installation for proper functioning. 4.3.2 Function types 4.3.2.1 Simple level converter The master function can be realized as a logically transparent level converter between the M-bus physical layer and some other (standardized) physical layer (e.g. V24). It is then bit transparent for allowable baud rates of 300 to BMax. No bit time recovery is possible. Hence a simple level converter cannot be used as a repeater. 4.3.2.2 Intelligent level converter An intelligent level converter can perform space bit time recovery for any asynchronous byte protocol at its maximum baud rate BMax. Other baud rates BMax/L (L = 2 to LMax) are allowed, but bit time recovery cannot be guaranteed for these other baud rates. Such a level converter can be used as a physical layer repeater for its maximum baud rate. 4.3.2.3 Bridge The master function can be integrated with a link layer unit thus forming a (link layer) bridge. If this bridge can support the required physical and link layer management functions it can support also multiple baud rates. 4.3.2.4 Gateway The master function can be integrated into the application layer of a gateway or it can be fully integrated into an application. 4.3.3 Requirements 4.3.3.1 Mark state voltage For currents between: ()02442IUVUV=+maxMarkr...:... 4.3.3.2 Space state voltage 12UUV<−SpaceMark, and 12UVU≥+Spacer'

SIST EN 13757-2:2018

EN 13757-2:2018 (E) 11 4.3.3.3 Bus short circuit Reversible automatic recovery shall guarantee full function not later than 3 s after the end of any current higher than IMax. 1 ms after the beginning of a short circuit situation the bus current shall be limited to < 3 A. 4.3.3.4 Minimum voltage slope The transition time between space state and mark state voltages from 10 % to 90 % of the steady-state voltages shall be

1/2 of a nominal bit time. The asymmetry of these transition times shall be

1/8 of a nominal bit time. Test conditions (CLoad selected from the E12 value series): — baud rate 300 Baud: CLoad = 1,5 F; — baud rate 2 400 Baud: CLoad = 1,2 F; — baud rate 9 600 Baud: CLoad = 0,82 F; — baud rate 38 400 Baud: CLoad = 0,39 F. 4.3.3.5 Effective source impedance The voltage drop of the bus voltage for a short (<50 ms) increase of the bus current by 20 mA shall be

1,2 V. 4.3.3.6 Hum, ripple and short-term (<10 s) stability of the bus voltages Hum, ripple and short-term (<10 s) stability of the bus voltages: < 200 mV peak to peak. 4.3.3.7 Data detection current (Reception of slave current pulses) Bus current

Bus idle current + 6 mA: Mark state receive. Bus current

Bus idle current + 9 mA: Space state receive. Measurement with current pulses of < 50 ms, duty cycle < 0,92. 4.3.3.8 Reaction at large data current (collision state, break signal) A current increase beyond a certain level shall be considered as a collision state. Current increases

25 mA shall never be detected as collision state. Current increases between 25 mA and 50 mA may be considered as collision state. Current increases of

50 mA shall be considered as collision state. For collision detection the collision state shall persist for at least 2 bit times at all supported baud rates. If a collision state persists for

50 µs the master shall not emit a break signal. If a collision state persists for > 50 µs to < 6,6 ms the master may emit a break signal. If a collision state persists for

6,6 ms the master shall emit a break signal. A break signal is characterized by a bus voltage = USpace and a duration of 40 ms up to 50 ms. This state shall also be signalled to the user side. If the bus current is > IMax, the master may switch off the bus voltage completely. Note that for voltage switch off the requirements for minimum recovery time (switch off time > 100 ms, please refer to SIST EN 13757-2:2018

EN 13757-2:2018 (E) 12 4.2.2.11) and for reversible automatic recovery and current limitation (refer to 4.3.3.3) shall be taken into account. 4.3.3.9 Galvanic isolation The isolation resistance between any bus terminal and all metal parts accessible without violating seals shall be > 1 M. The test voltage is 500 V. For mains powered masters or masters with connection to ground based systems (e.g. connection to the V24 port of a mains powered PC) this includes isolation from these power respective signal lines. For mains powered masters the appropriate safety rules apply. 4.3.3.10 Ground symmetry For mains powered masters or masters with connection to ground based systems (e.g. connection to the V24 port of a mains powered PC the static and dynamic bus voltages shall be symmetric (40 % to 60 %) with respect to ground. This requirement is only valid for ground based systems. 4.4 Electrical requirements mini-master 4.4.1 Definition of a mini-master A Mini-Master can be used in systems which can accept the following restrictions: — maximum wiring length of its segment:

50 m; — BMax: 2 400 baud; — no function required if any device fails with overcurrent; — no automatic search for secondary addresses (collision mode) required. A Mini-Master can be implemented as a simple level converter to some other standardized physical layer interface (e.g. V24) or it can be integrated into a data processing device. It usually cannot be used as a repeater. It can be implemented as a stationary or as a portable device. It can be powered from mains or it can be battery powered. 4.4.2 Requirements A Mini-Master has the following reduced requirements as compared to a full standard master: — Minimum transition slopes: For a load capacitance of 75 nF: Transition time between mark and space state voltages in both directions between 10 % and 90 % of the voltage step of the two static signal voltages: Maximum transition time tmax

— Behaviour at higher data currents (collision): No requirements. 4.5 Repeaters 4.5.1 General requirements A physical layer repeater shall meet at its slave side all requirements for a slave and at its master side all requirements of a master. Such a repeater is required in a net where one or several limits of the installation concerning maximum number of meters, maximum total cable length, maximum number of meters per segment or maximum distance are exceeded for the desired baud rate. SIST EN 13757-2:2018

EN 13757-2:2018 (E) 13 4.5.2 Additional requirements 4.5.2.1 Isolation The bus terminals at the master side shall be isolated from the bus terminals at the slave side. The isolation resistance shall be

1 M for the test voltage of 500 V. Any pertinent safety regulations for mains powered devices shall be considered. 4.5.2.2 Bit recovery Incoming data bytes with acceptable bit time distortions for a reception according to the requirements of the link layer used shall be transmitted at the other side in such a way that all the transmit timing requirements of the link layer are met. A repeater may therefore be restricted to certain baud rate(s) or may be restricted to certain byte formats or link layers. 4.6 Burst and surge requirements 4.6.1 General A device according to this standard shall fulfil at least the following burst and surge requirements according to EN 61000-4-4 and EN 61000-4-5 for the M-bus connection. Note that device standards might impose further requirements or might impose higher requirements regarding burst and surge. Note also that the values have been updated from EN 1434-3 due to field experience. 4.6.2 Requirements for devices intended for domestic use Burst test voltage: 1 kV (Severity class 2). 4.6.3 Requirements for devices intended for industrial use Burst test voltage: 1 kV (Severity class 2). Surge test voltage: 1 kV (Severity class 2). 5 Link Layer (master and slave) 5.1 General The alphabetic percent designations (e.g. “W %”) in the following clauses refer to the value specified in Table 1. 5.2 Baud rate 5.2.1 Required baud rate 300 Baud shall be supported. 5.2.2 Recommended additional baud rates 2 400 Baud, 9 600 Baud or 19 200 Baud are recommended. SIST EN 13757-2:2018

EN 13757-2:2018 (E) 14 5.2.3 Special baud rates By special arrangement between a net operator and a meter manufacturer also one or several of the following baud rates could be used: 600 Baud, 1 200 Baud, 4 800 Baud or 38 400 Baud. The total segment size and the number of connected slaves limits the technically safe maximum baud rate. (See cable installation section in Annex E). 5.2.4 Baud rate after reset The baud rate shall be kept after a reset of the device. 5

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