IEC 62026-1:2007

INTERNATIONAL IEC
STANDARD
CEI
62026-1
NORME
Second edition
INTERNATIONALE
Deuxième édition
2007-06
Low-voltage switchgear and controlgear –
Controller-device interfaces (CDIs) –
Part 1:
General rules
Appareillage à basse tension –
Interfaces appareil de commande-appareil (CDI) –
Partie 1:
Règles générales
Reference number
Numéro de référence
IEC/CEI 62026-1:2007
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INTERNATIONAL IEC
STANDARD
CEI
62026-1
NORME
Second edition
INTERNATIONALE
Deuxième édition
2007-06
Low-voltage switchgear and controlgear –
Controller-device interfaces (CDIs) –
Part 1:
General rules
Appareillage à basse tension –
Interfaces appareil de commande-appareil (CDI) –
Partie 1:
Règles générales
PRICE CODE
M
CODE PRIX
Commission Electrotechnique Internationale
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue
Pour prix, voir catalogue en vigueur

– 2 – 62026-1 © IEC:2007
CONTENTS
FOREWORD.3

INTRODUCTION.5

1 Scope.6

2 Normative references.6

3 Terms and definitions .7

4 Classifications .8

5 Characteristics.8
5.1 CDI components.8
5.2 Interfaces .8
5.3 Topology .9
5.4 Information exchanges.9
5.5 Attributes.9
6 Product information.9
6.1 Instructions for installation, operation and maintenance.9
6.2 Profiles.9
6.3 Marking .9
6.4 Degree of protection .10
7 Normal service, mounting and transport conditions.10
7.1 General .10
7.2 Normal service conditions.10
7.2.1 General .10
7.2.2 Ambient air temperature.10
7.2.3 Altitude .10
7.2.4 Climatic conditions.10
7.3 Conditions during transport and storage.10
7.4 Mounting .11
8 Constructional and performance requirements .11
8.1 General .11
8.2 Electromagnetic compatibility (EMC) .11
8.2.1 Immunity.11
8.2.2 Emission.12

8.2.3 EMC tests.12
9 Tests .12
9.1 General .12
9.2 Type tests .12
9.3 Electromagnetic compatibility.12

Table 1 – Immunity requirements .11

62026-1 © IEC:2007 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

CONTROLLER-DEVICE INTERFACES (CDIs) –

Part 1: General rules
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 62026-1 has been prepared by subcommittee 17B: Low-voltage
switchgear and controlgear, of IEC technical committee 17: Switchgear and controlgear.
This second edition of IEC 62026-1 cancels and replaces the first edition published in 2000.
It represents some general updating without technical changes with regard to the previous
edition.
The text of this standard is based on the following documents:
CDV Report on voting
17B/1505/CDV 17B/1544/RVC
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.

– 4 – 62026-1 © IEC:2007
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all parts of the IEC 62026, under the general title Low-voltage switchgear and

controlgear – Controller-device interfaces (CDIs), can be found on the IEC website.

The committee has decided that the contents of this publication will remain unchanged until the

maintenance result date indicated on the IEC web site under “http://webstore.iec.ch” in the data

related to the specific publication. At this date, the publication will be

• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
62026-1 © IEC:2007 – 5 –
INTRODUCTION
The class of controller-device interfaces (CDIs) covered in this International Standard includes

industrial CDIs for control systems, factory automation and process automation.

Industrial CDIs have proliferated to meet specific user needs, but no single CDI meets all

needs. The reason for multiple solutions is the wide range of physical, usage, information

content and configuration requirements. The physical requirements have resulted in CDIs with

widely differing signal and line conditioning mechanisms in order to meet distance, node count

and environmental considerations.

While there is wide variation in CDI technologies, there are common components, interfaces
and environmental requirements that are specified by this standard. Standardized definitions of
these common CDI requirements assist the user to compare and select technologies to match
the distance, node count, throughout and installation requirements for a specific application.
This standard simplifies the CDI selection process by providing a common structure for
generating a specific CDI’s IEC standard while also allowing specific interface features and
capabilities to be included. Clauses 1 to 8 contain the outline of general requirements that the
CDI’s IEC standard identifies. Clause 9 contains the test specification.
Standardization of CDI aspects also simplifies the task of writing the software for the higher
layer functions of industrial control systems, such as supervisory control, operator interface
and control strategy programming.
For this standard to be complete and usable, it requires the availability of specific CDI
standards, which make up the other parts of the IEC 62026 series.

– 6 – 62026-1 © IEC:2007
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

CONTROLLER-DEVICE INTERFACES (CDIs) –

Part 1: General rules
1 Scope
This International Standard applies to interfaces between low-voltage switchgear, controlgear,
and controllers (e.g. programmable controllers, personal computers, etc.).
This standard does not apply to higher level industrial communication networks that have
become known as fieldbuses and are considered by IEC subcommittee 65C.
The purpose of this standard is to harmonize and define rules, components and requirements
of a general nature applicable to industrial CDIs. Those features of the various CDI standards
which can be considered as general have therefore been brought together in this part of
IEC 62026.
For each CDI, two main documents are necessary to determine all requirements and tests:
a) this part, referred to as “IEC 62026-1” or “Part 1” in the relevant CDI parts covering the
various types of CDIs;
b) the specific CDI part of the IEC 62026 series.
A specific CDI part may omit a general requirement if it is not applicable, or it may add to it if it
is inadequate in the particular case, but it should not deviate from the requirement unless there
is substantial technical justification.
NOTE Product-specific requirements for products incorporating a CDI are given in the relevant product standards.
These requirements apply in addition to those given in this International Standard.
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.

IEC 60947-1:2007, Low-voltage switchgear and controlgear − Part 1: General rules
IEC 61000-4-2:1995, Electromagnetic compatibility (EMC) – Part 4-2: Testing and measure-
ment techniques – Electrostatic discharge immunity test
Amendment 1 (1998)
Amendment 2 (2000)
IEC 61000-4-3:2006, Electromagnetic compatibility (EMC) – Part 4-3: Testing and measure-
ment techniques – Radiated radio-frequency electromagnetic field immunity test
IEC 61000-4-4:2004, Electromagnetic compatibility (EMC) – Part 4-4: Testing and measure-
ment techniques – Electrical fast transient/burst immunity test
IEC 61000-4-5:2005, Electromagnetic compatibility (EMC) – Part 4-5: Testing and measure-
ment techniques – Surge immunity test

62026-1 © IEC:2007 – 7 –
EC 61000-4-6:2003, Electromagnetic compatibility (EMC) – Part 4-6: Testing and measurement

techniques – Immunity to conducted disturbances, induced by radio-frequency fields

Amendment 1 (2004)
Amendment 2 (2006)
IEC 61000-6-2:2005, Electromagnetic compatibility (EMC) – Part 6-2: Generic standards –

Immunity for industrial environments

CISPR 11:2003, Industrial, scientific and medical (ISM) radio-frequency equipment –

Electromagnetic disturbance characteristics – Limits and methods of measurement

Amendment 1 (2004)
Amendment 2 (2006)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
change of state
process of data exchange which occurs only when a device's or controller's data changes state
according to specific change criteria
3.2
controller
programmable controller, personal computer or equivalent computing hardware in which the
software controlling the application or process runs
3.3
controller-device communication medium
means (such as two or more wires or fibre optic cable) utilized by devices or controllers to
transfer data to other devices or controllers
NOTE A CDI that has "power on the communication medium" architecture uses two wires that also distribute
power within the CDI.
3.4
controller-device interface (CDI)
arrangement of nodes and their interconnections that transport information between controllers
and devices in an industrial control system
3.5
CDI component
device, controller or other component for which the requirements are specified in a CDI part
3.6
CDI power supply
power supply with characteristics and parameters suitable for the CDI's functionality and
capability
3.7
CDI power distribution medium
inter-connecting means used to transfer power within a CDI
NOTE In the case of a CDI that has "power on the communication medium" architecture, the CDI power
distribution medium also transfers data within the CDI.

– 8 – 62026-1 © IEC:2007
3.8
device
physical unit containing application elements and that may contain communication elements

EXAMPLES: Control circuit device (see 2.2.16 of IEC 60947-1), presence sensing device, pressure sensing device,

actuator, annunciator, operator terminal, motor controller, current sensor, valve control, data logger, bar-code

scanner, push-button, pilot light, etc.

3.9
device profile
representation of device functionality available to the CDI

3.10
multicast
process of data exchange which occurs when a device or controller produces one message to
multiple devices and/or controllers for their appropriate action
3.11
polling
process of data exchange which occurs when a device or a controller sends data to, or
requests data from, a specific device or controller
NOTE The receiving device responds to the polling by acting according to the data it receives or by returning its
status data. When this transaction is completed, the device polls the next device in a predetermined sequence.
3.12
strobing
process of data exchange which occurs when a device or a controller sends a single request
for data from one or more devices and/or controllers
NOTE Each device receiving the message then responds with its requested data in a predetermined sequence.
4 Classifications
This clause in the specific CDI parts shall list the classifications below, where applicable, with
appropriate details:
− CDI components;
− interfaces;
− topology;
− information exchanges;
− attributes.
5 Characteristics
This clause in the specific CDI parts shall list the applicable characteristics described below
with appropriate details.
5.1 CDI components
Specific CDI parts shall specify requirements for the devices, controllers and other components
that may be used.
5.2 Interfaces
Specific CDI parts shall include information on the following, if applicable:

62026-1 © IEC:2007 – 9 –
− procedural, such as what needs to happen first, second, etc. when the interface system

powers up and down, and establishes and terminates data exchange across the interface;

− information exchanges, such as what a device is requested to do across an interface;

EXAMPLE 1 Polling, change of state.

− services and protocol, i.e. the message structure and content that crosses the interface;

EXAMPLE 2 Peer-to-peer, master-slave.

− device and controller behaviour as viewed from the CDI;

− mechanical, i.e. the shape, construction, pin size, etc.;

− electrical, such as the voltage, current and timing of the bit levels on the CDI;

− functional, i.e. what interface connections provide which functions.
5.3 Topology
Specific CDI parts shall specify the topologies that may be used.
EXAMPLE Daisy chain, star, tree, trunk/drop.
5.4 Information exchanges
Specific CDI parts shall specify the information exchanges that may be used.
5.5 Attributes
Specific CDI parts shall specify the applicable attribute values including as a minimum:
− data transmission rate (in bits per second);
− maximum length of communication medium or end to end distance;
− message length for single transmission;
EXAMPLE 4 bits, 8 bytes.
− maximum node count per system;
and other information to support the evaluation of the transmission time of the CDI.
6 Product information
6.1 Instructions for installation, operation and maintenance
The manufacturer shall specify in the documents or catalogues, the conditions for installation,
operation and maintenance of the CDI components. The instructions shall specify the

measures to be taken, if any, for achieving EMC compliance as described in 8.2.
6.2 Profiles
Devices and controllers shall be marked with, or shall include in the instructions for operation,
identification of the device profile(s) supported.
6.3 Marking
CDI components shall be marked as follows:
a) manufacturer’s name or trade mark;
b) type designation or other marking which makes it possible to identify the CDI component
and to get the relevant information from the manufacturer or his catalogue;
c) reference to the relevant CDI parts;
d) any additional marking required by the relevant CDI parts.

– 10 – 62026-1 © IEC:2007
For CDI components that do not have the physical space to accommodate required markings,

the information shall be provided on a label or in the manufacturer's documentation.

6.4 Degree of protection
The manufacturer shall state the degree of protection according to Annex C of IEC 60947-1.

7 Normal service, mounting and transport conditions

7.1 General
The following requirements shall be met for all CDI components.
NOTE If the conditions for operation differ from those given in this standard or by the manufacturer, the user
should state the deviation from the standard conditions and acquire an agreement with the manufacturer on the
suitability for use under such conditions. Information given in the manufacturer's catalogue may take the place of
such an agreement.
7.2 Normal service conditions
7.2.1 General
All CDI components shall be designed and used according to the relevant CDI parts.
7.2.2 Ambient air temperature
The operating characteristics of all CDI components shall be maintained at least over the
ambient air temperature range of –5 °C to +40 °C.
7.2.3 Altitude
CDI components shall be capable of operating at altitudes of up to 2 000 m.
NOTE For CDI components intended to be used at higher altitudes, it is necessary to take into account the
reduction of the dielectric strength and the cooling effect of air.
7.2.4 Climatic conditions
7.2.4.1 Humidity
CDI components shall be capable of operating correctly at +40 °C with a relative air humidity of
50 % and with higher relative humidity at lower temperatures, for example 90 % at +20 °C.
Special measures may be necessary in cases of occasional condensation due to variations in
temperature.
7.2.4.2 Pollution degree
Unless otherwise stated by the manufacturer, CDI components shall be intended for installation
under environmental conditions of pollution degree 3, as defined in IEC 60947-1. However,
other pollution degrees may apply, depending upon the micro-environment.
7.3 Conditions during transport and storage
A special agreement shall be made between user and manufacturer if the conditions during
transport and storage, for example temperature and humidity, differ from those defined in 7.2.
Otherwise, the following temperature range applies during transport and storage: between –
25 °C and +55 °C and, for short periods not exceeding 24 h, up to +70 °C.

62026-1 © IEC:2007 – 11 –
7.4 Mounting
Mounting dimensions and conditions of the CDI components shall be specified in the specific

CDI parts or, if not specified, shall be stated in the manufacturer’s instructions.

8 Constructional and performance requirements

8.1 General
All products incorporating a CDI shall comply with their relevant product standards in addition

to this standard.
The constructional and performance requirements shall be specified in the specific CDI parts.
Requirements shall be specified for
− power supply,
− device,
− controller,
− electromechanical components,
− communication medium.
The requirements shall include but are not limited to
− general requirements,
− connections and ports,
− functions of the device or controller during initiating, sending, receiving and responding to
messages, I/O configuration and diagnostic messages,
− electromagnetic compatibility (EMC).
8.2 Electromagnetic compatibility (EMC)
8.2.1 Immunity
CDIs shall meet the minimum requirements given in Table 1, except where a different test level
is given and justified in the specific CDI parts.
Table 1 – Immunity requirements
Test levels Performance
Type of test
(where applicable) criterion
Electrostatic discharges 8 kV / air discharge B
IEC 61000-4-2 4 kV / contact discharge
Radiated radio-frequency electromagnetic fields 10 V/m A
(80 MHz to 1 GHz and 1,4 GHz to 2,0 GHz)
IEC 61000-4-3
Electrical fast transients/bursts 1 kV / 5 kHz for all cables that contain B
CDI communication media
IEC 61000-4-4
2 kV / 5 kHz for all other cables and
ports
2 kV (a.c. mains line-to-earth) B
Surges (1,2/50 μs − 8/20 μs)
IEC 61000-4-5 1 kV (a.c. mains line-to-line)
Conducted radio-frequency disturbances 10 V A
(150 kHz to 80 MHz)
IEC 61000-4-6
Voltage dips and interruptions See specific CDI parts

– 12 – 62026-1 © IEC:2007
Performance criteria and specified limits shall be given in the specific CDI parts using the

general performance criteria of IEC 61000-6-2.

8.2.2 Emission
CDIs shall meet the requirements given in CISPR 11 for class A, group 1.

These requirements apply to CDIs exclusively used in an industrial environment. When they

may be used in a non-industrial environment, the following warning shall be included in the

instructions for use:
Attention
This is a class A product. In a non-industrial environment, this product may cause radio
interference, in which case the user may be required to take adequate measures.

8.2.3 EMC tests
Electromagnetic compatibility tests shall be made in accordance with 9.3.
9 Tests
9.1 General
Tests shall be made to verify compliance with the requirements of this standard.
9.2 Type tests
Type tests are intended to verify compliance to this standard. Where applicable, they shall
include:
− power supply;
− device;
− controller;
− electromechanical components;

− communication medium.
They shall include, as appropriate, the verification of
− general requirements,
− connections and ports,
− functions of the device or controller during initiating, sending, receiving and responding to
messages, I/O configuration and diagnostic messages,
− electromagnetic compatibility (EMC).
9.3 Electromagnetic compatibility
The specific CDI parts shall detail the test methods and test set-ups.
Emission and immun
...