CLC/TS 50509:2007

SLOVENSKI STANDARD
01-januar-2008
Uporaba signalnih glav LED v sistemu cestne signalizacije
Use of LED signal heads in road traffic signal systems
LED-Signalgeber in Straßenverkehrs-Signalanlagen
Ta slovenski standard je istoveten z: CLC/TS 50509:2007
ICS:
93.080.30 Cestna oprema in pomožne Road equipment and
naprave installations
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION
CLC/TS 50509
SPÉCIFICATION TECHNIQUE
August 2007
TECHNISCHE SPEZIFIKATION
ICS 93.080.30
English version
Use of LED signal heads
in road traffic signal systems

This Technical Specification was approved by CENELEC on 2007-06-01.

CENELEC members are required to announce the existence of this TS in the same way as for an EN and to
make the TS available promptly at national level in an appropriate form. It is permissible to keep conflicting
national standards in force.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. CLC/TS 50509:2007 E
Foreword
This Technical Specification was prepared by Working Group 1 ‘Use of LED signal heads in road traffic
signal systems’ of CENELEC BTTF 69-3 ‘Road traffic signal system’.

The text of the draft was submitted to vote in accordance with the Internal Regulations, Part 2,
Subclause 11.3.3.3 and was approved by CENELEC as CLC/TS 50509 on 2007-06-01.

The following date was fixed:
– latest date by which the existence of the CLC/TS
has to be announced at national level (doa) 2007-12-01

This document contains specifications for the use of LED signal heads in road traffic signal systems in the
form of information with regard to the interpretation of existing standards and additional specifications,
dealing with specific technical properties of LED signal heads, not previously described in the existing
standards.
__________
- 3 - CLC/TS 50509:2007
Contents
1 Scope . 5
2 Normative references. 5
3 Definitions and abbreviations. 5
3.1 General definitions . 5
3.2 Optical definitions . 6
3.3 Electrical definitions and abbreviations. 6
4 Specification. 9
4.1 Existing standards . 9
4.2 Additional technical specifications . 9
4.3 Other issues . 14
5 Testing . 14
5.1 General . 14
5.2 Testing of the yellow optical unit. 14
6 Marking, labelling and product information . 14
Annex A (informative) Additional requirements under operating conditions - United Kingdom. 15
Annex B (informative) Dimmed operation - the Netherlands . 17
Annex C (informative) Dimmed operation - Spain . 18
Figure 1 - Luminous intensity and operating voltage. 10
Figure A.1 - Operation over voltage range. 15
Figure A.2 - Light output over voltage range. 15
Figure C.1 - Operation over voltage range. 18
Figure C.2 - Power consumption over voltage range . 18
Table 1 - Operating conditions (steady state) . 11
Table 2 - Switching-on (illumination) procedure . 12
Table 3 - Switching-off (extinction) procedure. 12
Table 4 - Fault response procedure. 13
Table 5 - Yellow optical unit test intervals . 14
Table A.1 - Additional electrical requirements. 16

Introduction
This document gives a specification for the mutual behaviour of traffic signal controllers and light-emitting
diode (LED) based signal heads in road traffic signal systems. The specification was written to contribute
to safe and reliable operation, while at the same time allowing the compatible operation of various types
and brands of signals and controllers.

Whilst the performance requirements for LED signals heads, as specified in the standards, remain
unchanged, various properties of composite LED signals that were implicit for incandescent lamps now
need to be described.
The market for LED signals has developed rapidly; products show considerable national or even regional
technical differences. This document intends to give guidance to the market for future development and
harmonisation.
It is the aim of this document to establish a minimum set of requirements that would allow both controllers
and signal heads to be tested separately. Where a controller or signal has been verified as compatible
with a class specified in this document, it would be deemed to function safely and securely in cooperation
with a signal or controller verified as compatible with the same class.

- 5 - CLC/TS 50509:2007
1 Scope
This Technical Specification considers only newly manufactured and installed signal controllers and
signal heads for road traffic applications, using appropriate cabling.

This Technical Specification considers only LED optical units with 200 mm and 300 mm roundels as
standardised in EN 12368. It does not consider configurations such as an arrow or a pedestrian symbol,
created by specifically positioned patterns of LEDs.

This Technical Specification does not consider railway signalling applications.

2 Normative references
The following referenced documents are indispensable for the application 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 12368, Traffic control equipment – Signal heads

EN 12675, Traffic Signal Controllers – Functional safety requirements

EN 50293, Electromagnetic compatibility – Road traffic signal systems – Product standard

EN 55015, Limits and methods of measurement of radio disturbance characteristics of electrical lighting
and similar equipment (CISPR 15)

EN 60825 series, Safety of laser products (IEC 60825 series)

EN 60950 series, Information technology equipment – Safety (IEC 60950 series)

EN 61000-2-2, Electromagnetic compatibility (EMC) – Part 2-2: Environment – Compatibility levels for
low-frequency conducted disturbances and signalling in public low-voltage power supply systems
(IEC 61000-2-2)
EN 61000-3-2, Electromagnetic compatibility (EMC) – Part 3-2: Limits for harmonic current emissions
(equipment input current up to and including 16 A per phase) (IEC 61000-3-2)

EN 61508 series, Functional safety of electrical/electronic/programmable electronic safety-related
systems (IEC 61508 series)
HD 638 S1, Road Traffic Signal Systems

3 Definitions and abbreviations
3.1 General definitions
3.1.1
road traffic signal system
see HD 638 S1
3.1.2
traffic signal controller
see EN 12675
3.1.3
signal head
see EN 12368
3.1.4
optical unit
see EN 12368
3.1.5
LED signal head
signal head, containing one or more optical units with light-emitting diodes as light source
3.2 Optical definitions
3.2.1
luminous intensity
see EN 12368
3.2.2
luminance uniformity
see EN 12368
3.2.3
dimmed operation
operating mode of the road traffic signal system in which the luminous intensity of the signal heads is
reduced, generally during the hours of darkness
3.3 Electrical definitions and abbreviations
3.3.1 Operating Conditions (Steady State) definitions and abbreviations
3.3.1.1
operating voltage U
IN
voltage value at the input terminals of the optical unit, whereby the luminous intensity corresponds to the
Class indicated in accordance with EN 12368. The voltage is a root-mean-square (r.m.s) value

3.3.1.2
relationship between luminous intensity and operating voltage
permissible change of the luminous intensity of the optical unit over the operating voltage range
U – U
ON IN,max
3.3.1.3
operating current I
IN
effective (r.m.s) values of the operating current over the operating voltage range U – U with the
ON IN,max
signal switched on and in the steady state
3.3.1.4
operating current window of measurement
period of time in each half-wave of the operating voltage in which the traffic signal controller can carry out
the current measurement for reliable signal monitoring
3.3.1.5
operating current trace inside the window of measurement
allowed deviation for the current profile compared to that that would be taken by a purely resistive load,
within the operating current window of measurement (see 3.3.1.4)

- 7 - CLC/TS 50509:2007
3.3.1.6
operating current trace outside the window of measurement
allowed deviation for the current profile compared to that that would be taken by a purely resistive load,
outside the operating current window of measurement (see 3.3.1.4)
3.3.1.7
power consumption at nominal value of the operating voltage P
IN,nom
power consumption of the optical unit at the voltage value U
IN,nom
3.3.1.8
power factor
see EN 61000-3-2
3.3.2
switching-on (illumination) related definitions and abbreviations
NOTE  Differences may exist in specifications depending on the meaning of a signal to road users. For the purpose of this
Technical Specification:
- “stop” indicates any signal and/or colour blocking traffic (generally: red);
- “go” indicates any signal and/or colour, permissive to traffic (generally: green and yellow).
3.3.2.1
switch-on interval – current T
SET,current
interval following the application of the operating voltage until the input current is above the minimum
operating current I
IN,min
3.3.2.2
switch-on interval – light T
ON,light
interval following the application of the operating voltage until the optical unit reaches the luminous
intensity in accordance with EN 12368, 6.3
3.3.2.3
switch-on voltage U
ON
operating voltage at which the optical unit reaches a luminous intensity of 10 cd (signal considered “on”).
The voltage is a root-mean-square (r.m.s) value
3.3.2.4
transient switch-on overcurrent interval T
ON,current
interval following the application of the operating voltage until the current is within specified limits of the
operating current
3.3.2.5
switch-on overcurrent I / I
ON IN,max
maximum permissible value (surge) over the operating current I during the interval T
IN,max ON,current
3.3.3 Switching-off (extinction) related definitions and abbreviations
3.3.3.1
switch-off interval - light T
OFF,light
interval following the removal of the operating voltage until the optical unit reaches a luminous intensity
less than 0,05 cd in the reference axis (signal considered “off”)
3.3.3.2
switch-off voltage U
OFF
operating voltage below which the luminous intensity is less than 0,05 cd in the reference axis (signal
considered “off”)
3.3.3.3
quiescent current – off I
OFF
input current for input voltages below the switch-on voltage U
ON
3.3.3.4
feedback voltage ratio U / U
REV IN,nom
residual voltage ratio measured over the optical unit, a specified interval after the removal of the operating
voltage, starting from the nominal value
3.3.3.5
optical unit resistance R
OFF
impedance of the unit measured on its terminals when no power is applied
NOTE  R is one method of ensuring that any induced voltage pickup on long signal cable runs is eliminated / dissipate before it
off
...