EN 50090-5-2:2020

SLOVENSKI STANDARD
01-junij-2020
Nadomešča:
SIST EN 50090-5-2:2005
Stanovanjski in stavbni elektronski sistemi (HBES) - 5-2. del: Mediji in nivoji,
odvisni od medijev - Omrežja, ki temeljijo na HBES razreda 1, zviti par
Home and Building Electronic Systems (HBES) Part 5-2: Media and media dependent
layers - Network based on HBES Class 1, Twisted Pair
Elektrische Systemtechnik für Heim und Gebäude (ESHG) - Teil 5-2: Medien und
medienabhängige Schichten - Netzwerk basierend auf ESHG Klasse 1, Twisted Pair
Systèmes électroniques pour les foyers domestiques et les bâtiments (HBES) - Partie 5-
2: Medias et couches dépendantes des medias - Réseau basé sur HBES Classe 1,
Paire Torsadée
Ta slovenski standard je istoveten z: EN 50090-5-2:2020
ICS:
35.240.67 Uporabniške rešitve IT v IT applications in building
gradbeništvu and construction industry
97.120 Avtomatske krmilne naprave Automatic controls for
za dom household use
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 50090-5-2

NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2020
ICS 35.100.20; 97.120; 35.100.10 Supersedes EN 50090-5-2:2004 and all of its
amendments and corrigenda (if any)
English Version
Home and Building Electronic Systems (HBES) Part 5-2: Media
and media dependent layers - Network based on HBES Class 1,
Twisted Pair
Systèmes électroniques pour les foyers domestiques et les Elektrische Systemtechnik für Heim und Gebäude (ESHG) -
bâtiments (HBES) - Partie 5-2: Medias et couches Teil 5-2: Medien und medienabhängige Schichten -
dépendantes des medias - Réseau basé sur HBES Classe Netzwerk basierend auf ESHG Klasse 1, Twisted Pair
1, Paire Torsadée
This European Standard was approved by CENELEC on 2020-01-09. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 50090-5-2:2020 E
Contents
European foreword . 4
Introduction. 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and abbreviations . 7
3.1 Terms and definitions . 7
3.2 Abbreviations . 8
4 Requirements for HBES Class 1, Twisted Pair Type 1 (TP1-64 and TP1-256) . 9
4.1 Physical layer requirements – Overview . 9
4.2 Requirements for analogue bus signals . 12
4.2.1 General . 12
4.2.2 Specification of logical “1” . 12
4.2.3 Specification of logical “0” (Single) . 13
4.2.4 Specification of logical “0” (overlapping) . 14
4.2.5 Analogue requirements within a transmitted character . 15
4.2.6 Simultaneous sending / collision behaviour . 16
4.3 Medium attachment unit (MAU) . 16
4.3.1 General . 16
4.3.2 Requirements within a physical segment . 16
4.3.3 Remote powered devices (RPD) . 24
4.4 Twisted Pair Type 1 bus cable . 25
4.4.1 Requirements . 25
4.4.2 Measurement of continuous magnetic and electrical interference
respectively transient induced differential voltages . 26
4.5 Topology . 27
4.5.1 Physical segment . 27
4.5.2 Bridge . 27
4.5.3 Router, subline, main line and zone . 28
4.5.4 Gateways to other networks . 29
4.6 Services of the physical layer type Twisted Pair Type 1 . 30
4.6.1 General . 30
4.6.2 Physical_Data service . 30
4.6.3 Physical_Reset service . 32
4.7 Behaviour of the physical layer type Twisted Pair Type 1 entity . 32
4.8 Data link layer type Twisted Pair Type 1 . 32
4.8.1 General . 32
4.8.2 Frame formats . 33
4.8.3 Medium access control . 38
4.8.4 Data link layer services . 41
4.8.5 Data link layer protocol . 44
4.8.6 State machine of data link layer . 46
4.8.7 Parameters of data link layer . 46
4.8.8 Reflections on the system behaviour in case of L_Poll_Data
configuration faults . 47
4.8.9 The data link layer of a bridge . 47
4.8.10 The data link layer of a router . 47
4.8.11 Externally accessible bus monitor and data link layer interface . 47
Bibliography . 48

European foreword
This document (EN 50090-5-2:2020) has been prepared by CLC/TC 205, “Home and Building Electronic
Systems (HBES)”
The following dates are fixed:
• latest date by which this document has (dop) 2020-10-10
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2023-04-10
standards conflicting with this document
have to be withdrawn
This document will supersede EN 50090-5-2:2004 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
EN 50090-5-2 is part of the EN 50090 series of European Standards, which will comprise the following
parts:
— Part 1: Standardization structure;
— Part 3: Aspects of application;
— Part 4: Media independent layers;
— Part 5: Media and media dependent layers;
— Part 6: Interfaces;
— Part 7: System management;
NOTE Part 2 has been withdrawn.
———————
This document was prepared with the help of CENELEC co-operation partner KNX Association, De Kleetlaan 5, B-
1831 Diegem.
Introduction
According to OSI, Physical Layers consist of the medium, the cable, the connectors, the transmission
technology etc. which refers to their hardware requirements. In this document however, the status of the
Physical Layer as a “communication medium” is emphasized.
1 Scope
This document defines the mandatory and optional requirements for the medium specific physical and
data link layer for HBES Class 1 Twisted Pair TP1.
Data link layer interface and general definitions, which are media independent, are given in
EN 50090-4-2.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 50090-1, Home and Building Electronic Systems (HBES) — Part 1: Standardization structure
EN 50090-2-2, Home and Building Electronic Systems (HBES) — Part 2-2: System overview — General
technical requirements
EN 50090-3-2, Home and Building Electronic Systems (HBES) — Part 3-2: Aspects of application — User
process for HBES Class 1
EN 50090-4-2, Home and Building Electronic Systems (HBES) — Part 4-2: Media independent layers —
Transport layer, network layer and general parts of data link layer for HBES Class 1
EN 50290 (series), Communication cables
EN 61000-4-5, Electromagnetic compatibility (EMC) — Part 4-5: Testing and measurement techniques —
Surge immunity test (IEC 61000-4-5)
EN 61000-6-1, Electromagnetic compatibility (EMC) — Part 6-1: Generic standards — Immunity for
residential, commercial and light-industrial environments (IEC 61000-6-1)
EN 61000-6-2, Electromagnetic compatibility (EMC) — Part 6-2: Generic standards — Immunity for
industrial environments (IEC 61000-6-2)
HD 21.2 S2, Polyvinyl chloride insulated cables of rated voltages up to and including 450/750 V — Part 2:
Test methods (IEC 60227-2)
HD 22.2 S2, Rubber insulated cables of rated voltages up to and including 450/750 V — Part 2: Test
methods (IEC 60245-2)
IEC 60189-2, Low-frequency cables and wires with PVC insulation and PVC sheath — Part 2: Cables in
pairs, triples, quads and quintuples for inside installations
IEC 60332-1, Tests on electric cables under fire conditions — Part 1: Test on a single vertical insulated
wire or cable
IEC 60754-2, Test on gases evolved during combustion of materials from cables — Part 2: Determination
of acidity (by pH measurement) and conductivity
3 Terms, definitions and abbreviations
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 50090-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
HBES class 1 twisted pair type 1
physical layer specification for data and power transmission on a single twisted pair, allowing
asynchronous character-oriented data transfer in a half-duplex, bi-directional communication mode, using
a specifically balanced/symmetrical base-band signal coding with collision avoidance under SELV
conditions
3.1.2
distributed power supply
powers the bus in a distributed way by a number of the devices connected to the line (compared to a
centralized power supply)
3.1.3
logical tag extended HEE
usage of the L_Data_Extended frame dedicated to extended group addressing
3.1.4
remote powered devices
RPD
do not extract their energy for the application circuit and the bus controller from the bus but from another
independent source of energy, e.g. mains
Note 1 to entry: Owing to the reduced DC power consumption of RPD, a bus line equipped with such devices
requires less power from the installed Power Supply Unit (PSU). The connection of bus-controller and application to
the same electrical potential reduces the effort of galvanic separation in RPD.
3.1.5
TP1 backbone couplers
15 can be used to couple up to 16 zones to a full sized TP1 network
3.1.6
TP1 backbone line
main line of the inner zone is called backbone line
3.1.7
TP1 bridge
four TP1-64 physical segments can be combined to a line by using bridges
Note 1 to entry: 256 devices can then be connected to such a line.
3.1.8
TP1 line
consists of a maximum of 256 devices, either directly connected in case of TP1-256 or separated over 4
physical segments in case of TP1-64, each with 64 devices
3.1.9
TP1 line couplers
routers that combine lines to a zone
3.1.10
TP1 logical unit
converts the serial bit stream to octets and octets to the serial bit stream, which is a serial stream of
characters
3.1.11
TP1 medium access unit
converts information signals to analogue signals and vice versa, typically extracts DC power from the
medium
3.1.12
TP1 main line
inner line of a zone
3.1.13
TP1 physical segment
smallest entity in the TP1 topology
Note 1 to entry: To a physical segment up to 64 devices can be connected in case of TP1–64 and 256 in case of
TP1–256.
3.1.14
TP1 Polling Master
Poll_Data master
device transmitting the Poll_Data frame
3.1.15
TP1 polling slave
Poll_Data slave
device transmitting a Poll_Data character
3.1.16
TP1 router
acknowledges frames on data link layer and transmits the received frame on the other side of the router,
provided the device associated with the destination address is located on the other side
3.1.17
TP1 sub-line
outer lines of a zone
3.1.18
TP1 zone
16 TP1 lines can be connected to a zone by using 15 routers
3.2 Abbreviations
AC alternating current
ACK acknowledge
APDU application layer protocol data unit
AT address type
CSMA/CA carrier sense, multiple access with collision avoidance
CKS checksum
DA destination address
DC direct current
DL TP data link layer type twisted pair
DPS distributed power supply
CTRL control field
HBES Class 1 refers to simple control and command
HBES Class 2 refers to class 1 plus simple voice and stable picture transmission
HBES Class 3 refers to class 2 plus complex video transfers
IFT inter-frame-time
LC line coupler
LN length
LPDU link layer protocol data unit
LSDU link layer service data unit
LTE-HEE logical tag extended hee
MAU medium attachment unit
NACK negative acknowledge
NPCI network layer protocol control information
NRZ non-return-to-zero
OCP over-current protection
PELV protective extra low voltage
PDU protocol data unit
PSU power supply unit
RPD remote powered bus devices
RUP reverse polarity protection
SA source address
SDU service data unit
SELV safety extra low voltage
TP twisted pair
TPDU transport layer protocol data unit
UART universal asynchronous receiver transmitter
up power up
4 Requirements for HBES Class 1, Twisted Pair Type 1 (TP1-64 and TP1-256)
4.1 Physical layer requirements – Overview
The Physical Layers described in this clause are called Physical Layer type twisted pair TP1-64 and
twisted pair TP1-256. The main differences are shown in Table 1. TP1-256 is backwards compatible
towards TP1-64. If common features of TP1-64 and TP1-256 are described, only the expression TP1 is
used.
The Twisted Pair medium TP1 characteristics are:
— data and power transmission with one pair of wires;
— asynchronous character-oriented data transfer;
— half duplex bi-directional communication;
— a specifically balanced/symmetric base-band signal coding under SELV conditions.
All characteristics given in the following subclauses, for instance maximum number of devices or possible
cable length per physical segment are only valid for cable complying to the requirements as shown in 4.4
)
and for TP1 devices of which bus power consumption does not exceed 12 mA .
Table 1 — System parameters of physical layer Type TP1–64 and TP1–256
Characteristics Description TP1–64 Description TP1–256
Medium a
Shielded twisted pair
Topology Linear, star, tree or mixed
Baud rate 9 600 bps
Device supplying Normal: bus powered devices - optional: remote powered
devices
Device power consumption 3 mA to 12 mA
Power Supply Unit (PSU) DC 30 V
Number of PSUs per physical Maximum 2
segment
Number of connectable devices per Maximum 64 Maximum 256
physical segment
Number of addressable devices per b Maximum 255
Maximum 255
physical segment
Total cable length per physical Maximum 1 000 m
segment
Distance between two devices Maximum 700 m
Total number of devices in a network More than 65 000 (with More than 65 000
bridges)
Protection against shock SELV (Safety Extra Low Voltage)
Physical signal Balanced/symmetric baseband signal encoding
a
The shield is not mandatory, shielded cables with earth connection can improve noise immunity.
b
In TP1–64 a physical segment can be extended with up to 3 extra physical segments, each connected to it via a
bridge. Every physical segment can contain 63 devices.
Figure 1 shows the logical structure of the physical layer type TP1 entity. Every device includes one;
every router and bridge is equipped with two such physical layer type TP1 entities.
The physical layer type TP1 entity consists of four blocks:
— cable (medium);
— connector, connecting a device or a bridge to the transmission medium;
— a Medium Attachment Unit (MAU);
———————
2)
Fan-in model allowing devices of which the bus power consumption is higher is under consideration.
— logical unit.
Figure 1 — Logical structure of physical layer type TP1
Figure 2 shows the relationship between the bits of an octet and the Universal Asynchronous Receiver
Transmitter (UART) character data bits.

Figure 2 — Octet mapped to a serial character
4.2 Requirements for analogue bus signals
4.2.1 General
In the underneath description, U is an internal reference voltage for the DC part of the bus voltage,
REF
used by the transmitter/receiver for evaluating the sent/received signal levels. This reference voltage is
sampled before the start bit of a byte. This U may vary with the values given in 4.2.5.
REF
The underneath specifications classify a 0 and 1 signal on the bus: the requirements for signal generation
and extraction for the transmitter and receiver respectively are defined in 4.3.2.6 and 4.3.2.7.
4.2.2 Specification of logical “1”
A logical “1” shall be regarded as the idle state of the bus, which means that the transmitter of a MAU
shall be disabled during sending a “1”. The analogue signal at the bus consists normally only of the DC-
part. There is no difference between sending a “1” and sending nothing. A decline of voltage during a “1”
may occur, if a ‘0 bit’ was preceding. The graph shall be within the shaded areas of Figure 3.

Figure 3 — “1”-Bit frame
The characteristics of a logical 1 signal shall follow the values given in Table 2.
Table 2 — Analogue and digital signal of a logical “1”
Parameter Value
Bit-time 104 µs
Voltage (DC-part) 21 to 32 V DC
Slopes (AC-part) Maximum 400 mV/ms
4.2.3 Specification of logical “0” (Single)
A logical “0” shall be a defined voltage drop (U ) of the analogue bus signal with a duration of t (see
a active
Figure 4). During the following equalization time the voltage may be higher than the DC-part to enable
recharging of energy consumed during the active part. The graph shall be within the shaded areas of
Figure 4.
Figure 4 — “0”-Bit frame
The characteristics of a logical “0” signal shall follow the values given in Table 3.
Table 3 — Analogue and digital signal of logical “0”
Parameter / Point Minimum Maximum
Bit-time 104 µs (typical)
t 35 µs (typical)
active
t (time between Ua > A and Ua > B) 25 µs 70 µs
s
(see also 0)
Time (Point D - E) 50 µs
Voltage (DC-part) 21 V 32 V
Voltage Ua (Point A) compared to Ref - 0,7 V - 10,5 V
Voltage Ua (Point B) compared to Ref - 0,1 V - 10,5 V
Voltage Ue (Point C - D) compared to Ref 0 V + 13 V
Voltage Uend (Point F) compared to Ref - 0,35 V + 1,8 V
4.2.4 Specification of logical “0” (overlapping)
Overlapping means, that a logical “0” is transmitted at the same time by several devices (e.g. common
ACK). Owing to the propagation delay of the bus cable (PhL-Medium) a time shift of logical zeros can
occur, if sending devices are located at a distance from the receiving devices. The MAU and the Logical
Unit shall be able to detect and interpret these signals. Figure 5 shows an example of two mixed logical
“0” that have a delay (td) of about 10 µs. Assuming that the point of measuring is at device A, the signal of
device B appears after 10 µs with a lower signal amplitude than device A, as it has been damped along
the bus cable.
Figure 5 — Delayed logical “0”
Figure 6 — Overlapping of two logical “0” (example)
The receiver of the MAU converts this mixed analogue signal to a digital signal. This digital signal differs
from that of a normal “0”, because the width of the receiver’s output pulse is the sum of t + td.
active
However, it is possible, that the receiver’s output delivers a gap at the end of t (See shaded area in
active
Figure 6.) This behaviour requires dedicated decoding software that is able to decode such effects.
4.2.5 Analogue requirements within a transmitted character
4.2.2 and 4.2.3 describe the voltage shape and timing when transmitting a single logical bit. When
transmitting an entire character (consists of a series of bits), the additional requirements of Table 4 shall
be met. The values Ua* and Ue* are referred to Uref at the beginning of the active part of the first bit of
the transmitted character.
Table 4 — Limits within a character
Parameter Value
Ua* Maximum - 10,5 V
Ue* Maximum 11,5 V
Uref (any bit) Maximum - 1 V / + 3 V
4.2.6 Simultaneous sending / collision behaviour
Although devices shall investigate the bus line before they begin sending, it is possible that two or more
devices send simultaneously. Simultaneous sending of a character occurs when two or more devices
simultaneously transmit ACK, Negative Acknowledgement (NACK) or BUSY messages.
Simultaneous transmission of a logical “0” and a logical “1” will result in a logical “0”.
Simultaneous sending of logical “0” by several devices will result in a signal that is nearly identical to that
of a single transmitting device, as signals are coded in the baseband.
This common signal shall therefore also comply with the values given in Table 2.
If a sending device detects that its own logical “1” was overwritten by another logical “0”, transmission
shall be disabled after this bit. Receiver of both devices shall however remain active.
This behaviour of the physical layer allows a CSMA/CA medium access in data link layer (see 4.8).
4.3 Medium attachment unit (MAU)
4.3.1 General
The medium attachment unit (MAU) shall split the analogue signal of the medium into the DC part and the
serial bit stream. Vice versa the serial bit stream shall be converted to the analogue bus signal.
The DC-part may be used internally to supply the device with power by using a DC/DC converter or
voltage regulator. A wrongly connected MAU shall neither damage the device nor influence the bus
communication.
4.3.2 Requirements within a physical segment
4.3.2.1 General
Within a physical segment the following principal requirements shall be met:
— in an installed system the DC voltage at every device shall be at least 21 V. Devices shall continue to
operate with a DC voltage down to 20 V. The difference between 20 V and 21 V has been laid down
as a reserve;
— the propagation delay of the serial bit stream at the MAU shall be short enough to allow bit-wise
CSMA/CA arbitration during a bit time. The total delay (MAU - Cable - MAU) shall not exceed 12 µs.
Refer also to 4.8.3;
— the Power Supply Unit [PSU(s)] connected to a physical segment shall provide the necessary
effective current required by the devices connected to the physical segment;
SELV requirements shall be met according to EN 50090-2-2.
4.3.2.2 Power up behaviour
Powering up means, that either a single bus device is installed in a ‘running’ bus segment or a PSU is
switched on in a fully equipped bus segment. The rising of the bus voltage is different. Power up
behaviour can be divided into two steps:
— during Start-up, the internal capacitors are being charged with a current limitation;
— during Operation, the capacitors are charged, voltages are constant.
Power up behaviour requires, that
— bus devices run up properly regardless the installed (allowed) topology, when the associated
segment is powered on by the PSU (slow ramp);
— a single bus device runs up properly if installed in an operating bus segment. Other bus devices
already installed in this segment shall not suffer a ‘reset’ owing to the installation of this additional
bus device (steep ramp);
— a possible signal disturbance, caused by the installation of a single bus device in an operating
segment shall not exceed 20 ms, in order to avoid telegram losses.
4.3.2.3 Power down behaviour
The Power down behaviour occurs when the input to the power converter of the device breaks down. This
input can either be the DC part of the bus voltage or a remote power source (see 4.3.3).
The Power Down behaviour can be divided into three steps:
— during Operation, the capacitors are charged, voltages are constant;
— during hold-up, the Capacitors are discharged;
— during Idle, the power converter draws only a leakage current.
When passing from operation to hold-up, the physical layer may generate a U signal:
save
— to allow devices to backup data before power breaks down,
— to disable further transmission of telegrams by the bus device.
For bus powered devices, this U signal shall be generated when the bus voltage drops below
save
maximal 20 V, thereby taking into account a hysteresis of at least 1 V.
The physical layer shall generate a Reset Signal U when the correct functioning of the power
reset
converter can no longer be ensured, typically before the end of the hold-up time. Determination of the
correct functioning may be manufacturer specific. For a bus powered device the U signal shall not be
reset
generated for input voltages higher than U .
save
4.3.2.4 DC behaviour
Bus devices shall not draw more than the DC bus current as laid down in Table 5, in order to ensure that
the maximum number of connectable devices per segment defined in the system parameters (Table 1)
can be installed. This current shall not be exceeded in worst case (20 V bus voltage and maximum
application power consumption). The manufacturer shall specify this DC current in the product datasheet.
Load changes within a device shall not disturb the signal voltage from the bus in any way. Fast current
changes inside a device shall be transformed (smoothened) to slow slopes on the bus side.
Table 5 — Unit currents for standard devices
Parameter TP1–64/TP1–256
Bus current (at 20 V – 32 V) Maximum 12 mA
Slope of input current Maximum 0,5 mA/ms
Slope of input current for Maximum 2,5 mA/ms
manually operated devices
(e.g. push buttons)
4.3.2.5 Impedance behaviour
The impedance of a device is not only a property of the receiver but of the complete device. The current
drawn from the bus by a device when the bus voltage has the shape of a square pulse (35/104 µs)
determines the impedance behaviour. The impedance value within a pulse (T = 104 µs) is however not
constant. The value during the active part (t < 35 µs) is different from the one during the equalization part.
Impedance matching is important to ensure that signal damping is not too high and following bits are not
disturbed by the equalization event of preceding bits.
4.3.2.6 Transmission behaviour
If no frame is transmitted, the voltage between Bus (+) and Bus (-) lies between 21 V to 32 V DC. This
value is determined by the PSU, the voltage drop along the bus cable and the consumption of the
devices. This state of the medium over a bit time of 104 µs corresponds to a logical “1”. The logical “1”
also indicates the idle state when no frame is transmitted. The related output signal to the PhL Logical
Unit by the MAU is „OFF“ during the entire bit time.
In order to transmit a logical “0”, the MAU shall draw an adapted current (I ) to cause a defined
send
voltage drop U of the analogue signal with a duration of t (see also Table 3).
a active
During the following equalization time the energy consumed during the active time may be partly charged
back to the bus cable and the connected devices. In this way, bus-powered devices shall not suffer a
significant power drop during transmission of a logical “0”. The AC part of the analogue signal shall be
mainly generated by the transmitter of the MAU and the choke(s). Figure 7 provides an example of a
transmission method.
Figure 7 — Method of transmitting
The value of I of a device depends on:
send
— number of connected bus-devices,
— number of bus-devices that are sending simultaneously (e.g. in case of ACK),
— bus voltage,
— segment cable length.
Tables 6 and 7 provide the requirements for TP1–64 and TP1–256 transmitters, whereas Figure 8 shows
examples of transmitter characteristics.
Table 6 — Dynamic requirements of a TP1–64 transmitter
Parameter Minimum value Maximum value
I approximately b
send 400 mA
a
0 mA
c 3 V 9 V
U
A
a
Valid for one device if maximum number of devices are sending
simultaneously.
b
Valid if only one device is sending and the segment is equipped
with maximum number of devices.
c
Measured at the device.
Table 7 — Dynamic requirements of a TP1–256 transmitter
Parameter Minimum value Maximum value
I approximately 400 mA
send
0 mA
U 3 V 10 V
A
Figure 8 — Example of transmitter characteristics
Figure 9 shows an example of a principle diagram of a TP1-64 transmitter:
NOTE 1 Only during the active part (35 µs) of “Logical 0” S1 and S2 are closed. At any other time, they are both
open.
NOTE 2 RVP = Reverse Polarity Protection Switch (Voltage drop < 0,5 V).
Figure 9 — Example of a diagram of a TP1-64 transmitter
Figure 10 shows an example of a principal diagram of a TP1-256 transmitter:
Figure 10 — Example of a diagram of a TP1-256 transmitter (I 0,4 A)
limit
4.3.2.7 Receiving behaviour
The MAU shall convert an analogue signal to a digital signal by using a receiver function (see Figure 1).
The required threshold voltages for the receiver are shown in Table 8. The relation of ON/OFF and the
bus voltage are explained in Table 3.
Table 8 — Requirements for the receiver
State at MAU Threshold Voltage TP1–64 Threshold Voltage TP1–256
(relative to DC part) (relative to DC part)
ON 0,5 V (typical) 0,6 V (typical)
OFF 0,2 V (typical) 0,3 V (typical)
4.3.2.8 Signal coding
The Logical Unit shall convert framed data bits into an asynchronous timed serial signal. This signal shall
be used to drive the transmitter of the MAU. Figure 11 shows an example of a digital signal and the
resulting serial bit stream. Table 9 details requirements for bit coding.
Figure 11 — Relation between framed data and asynchronous signal
Table 9 — Requirements for bit coding
Parameter Minimum Typical Maximum
Bit time  104 µs
Pulse duration 34 µs 35 µs 36 µs
Time from startbit to following (n x 104) – 2 µs n x 104 µs (n x 104) + 2 µs
bits (within a byte)
Time from start-bit to startbit of (13 x 104)-2 µs 13 x 104 µs (13 x 104) + 30 µs
consecutive bytes
Additional timing information and structure of telegrams is given in 4.6 and 4.8.
4.3.2.9 Signal decoding
The output signal of the receiver, regarded as a digital signal, shall be decoded to the serial bit stream by
the bit decoding unit of the MAU (see also Figure 1). The following Figure 12 shows an example of a
digital signal and the resulting serial bit stream.

Figure 12 — Relation between digital signal and serial bit stream
The bit-decoding unit of the MAU shall use an acceptance time window. The beginning of the acceptance
time window is defined in relation to the start bit. In addition minimum and maximum pulse duration are
laid down. The corresponding values are listed in the following table (Table 10):
Table 10 — Requirements for the bit decoding unit
Parameter Minimum Typical Maximum
Bit time 104 µs
Pulse duration 25 µs 35 µs a
70 µs
Acceptance window for the
(n x 104) - 7 µs n x 104 µs (n x 104) + 33 µs
rising slope of a bit n,
referred to rising edge of
start bit (=Ref. point)
Time distance from start bit (13 x 104) - 13 x 104 µs (13 x 104) + 30 µs
to start bit within a frame 30 µs
a
See also Table 4.
The physical layer shall guarantee that the transmission of a logical “0” is dominant versus the
simultaneous transmission of a logical “1”. It shall also guarantee that during the simultaneous
transmission of bits of equal value by several devices, the resulting physical signal corresponds to the
same logical value of the bit sent. This behaviour of the physical layer allows a CSMA/CA medium access
in data link layer (see 4.8.3).
4.3.3 Remote powered devices (RPD)
4.3.3.1 General
RPD shall only draw a minimal DC current from the bus line (segment). The AC load shall be similar to a
standard device. Only the transceiver shall be supplied from the bus line.
Figure 13 shows an example of a remote powered device.

Figure 13 — Example of a light dimmer
4.3.3.2 Reset and save behaviour of remote power bus device
The device supply voltage shall be implemented as master voltage. Power up or power down of this
source may cause reset, save and init. Save and init are the routines that may be defined in the user
program. They may be executed when the device detects either power up or power down of the supply
voltage. The missing of master voltage shall not disturb the operating bus segment in any way.
Bus voltage shall be implemented as slave voltage. When the bus power breaks down, the RPD shall
refrain from further transmission attempts. When the bus power is restored, the RPD shall continue
normal operation.
NOTE This is a general requirement, also valid for purely bus-powered devices. This is part of the properly
powering up of devices as specified in 4.3.2.2.
The behaviour of the device if either master or slave voltage is missing, shall be described in the
manufacturer’s data sheet.
The manufacturer shall define how to reset a RPD. The device may be forced to a reset from the bus
side, through the transmission of a special reset service message.
4.4 Twisted Pair Type 1 bus cable
4.4.1 Requirements
The below mentioned requirements for TP1 cable ensure that distances as specified in 4.5 can be met.
Table 11 — Requirements for TP1 cable
No. Features Requirements Test

1 Electrical properties Loop resistance Maximum 75 Ω/km Measurement
2.1 Outer sheath Required -
2.2 Insulation 100 MΩ/km (20°) Measurement
resistance core to respectively 0,011 MΩ/km
outer sheath (70°)
2.3 Withstand voltage 800 V Measurement
core/core
2.4 High voltage 2 kV AC 50 Hz 5 min
withstand
a 1 min
Electrical safety
4 kV AC 50 Hz
All cores and
screen connected
with each other
against outer
sheath surface,
immersed in water
according to
HD 21.2 S2 and
HD 22.2 S2
3.1 Twist Minimum 5/m Measurement
3.2 Continuous U ≤ ± 200 mV peak See 0
magnetic and (50 Hz – 1 GHz)
electrical
interference fields
3.3 Transient induced U ≤ ± 45 V peak for level 1: See 0
differential cable length as specified in
voltages 4.5 and transient voltages
EMC
according to industrial level
(according to EN 61000-6-2)
or home level (according to
EN 61000-6-1)
3.4 Screen - shall cover entire -
diameter
- drain wire: diameter
minimum 0,4 mm
4 Temperature and  b According to
According to IEC 60189-2 ,
climate IEC 60189-2,
alternatively EN 50290
alternatively
series
EN 50290 series
No. Features Requirements Test

5 Mechanical stress  b According to
According to IEC 60189-2 ,
IEC 60189-2,
alternatively EN 50290
alternatively
series
EN 50290 series
6.1 Capacity wire/wire Minimum 10 nF/km Measurement
Communication
Maximum 100 nF/km
(10 kHz)
6.2  Inductance Minimum 450 µH/km Measurement
Maximum 850 µH/km
(10 kHz)
6.3 Communication ≤ 50 kHz 15 dB/km
50 kHz to 15 dB/km to
500 kHz c
35 dB/km
Maximum signal
Measurement
0,5 MHz to 35 dB/km to
attenuation
5 MHz c
95 dB/km
5 MHz to 95 dB/km to
c
25 MHz
200 dB/km
a
In some countries this 4 kV test is required.
b
For halogen free cable, IEC 60189-2 shall be used as far as applicable. In addition IEC 60332-1 and
IEC 60754-2 shall be complied with.
c
Increasing linearly with the logarithm of the frequency.
4.4.2 Measurement of continuous magnetic and electrical interference respectively transient
induced differential voltages
4.4.2.1 Test set-up
Test shall be carried out with a cable length of 50 m.
The cable shall be laid in such a way that the induction is low (straight or with meanders of approximately
20 cm, not rolled up).
The cable causing interference (primary loop: single wire or cable with go and return wire) shall be laid
parallel to the bus cable to be tested over its entire length.
The distance between the interfering cable and the bus cable shall be chosen in such a way that the
highest possible coupling (that can arise in the field) is reached.
The source of the transient voltages shall be connected to the primary loop with respectively 2 Ω/12 Ω
and the corresponding coupling capacitor. A combination wave generator according to EN 61000-4-5 with
1,2/50 µs impulse shall generate the transient voltages. The generator shall be coupled to the primary
loop as for mains connections according to EN 61000-4-5.
On one side the bus cable wires shall be connected to the ground with 100 Ω each. On the other side the
bus cable shall be short-circuited (this side shall never be connected to ground).
The following values for transient voltages (industry level according to EN 61000-6-2 or for home level
according to EN 61000-6-1) shall be met: peak voltage 1 kV with Ri = 2 Ω and peak voltage 2 kV with
Ri = 12 Ω.
The induced voltage on the bus cable shall be measured as differential voltage.
4.4.2.2 Requirements
The relevant requirements of Table 11 shall be met.
NOTE The relevant requirement of 4.4 will be replaced by a reference to the specification for TP1 cables,
currently under consideration in CLC/TC 46XC in the forthcoming EN 50288-13 series when available.
4.5 Topology
)
4.5.1 Physical segment
The topology of a physical segment may be a linear, star or tree or mixed topology (see Figure 14). Up to
64 (TP1-64) or 256 (TP1-256) devices may be connected to a physical segment, provided bus cable
complying to the requirements of Table 11 is used. 256 devices correspond to the logical address space
of a bus line (see 4.8.2.4.3). The maximum distance between two devices in a physical segment shall not
exceed 700 m. The maximum cable length in a tree or star topology may be longer than the maximum
distance between two devices. Therefore the maximum cable length of a physical segment shall not
exceed 1 000 m for the cables complying with the requirements of Table 11.
Loops within a physical segment are allowed but not recommended.
Terminating resistors are not required.

Figure 14 — Physical segments
4.5.2 Bridge
The bridge shall guarantee a galvanic separation of the connected physical segments to improve noise
immunity. By using bridges, the maximum cable length can be extended to 3 000 m. The maximum
distance between two devices in a line can therefore also be extended to 700 m x 3 = 2 100 m for cables
complying with the requirements of Table 11 It is allowed that bridges do not have an Individual Address.
They shall however acknowledge the frames they receive on Data Link Layer and transmit the received
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