EN 60654-2:1997

SLOVENSKI STANDARD
01-december-1998
Operating conditions for industrial-process measurement and control equipment -
Part 2: Power (IEC 60654-2:1979 + A1:1992)
Operating conditions for industrial-process measurement and control equipment -- Part
2: Power
Einsatzbedingungen für Meß-, Steuer- und Regeleinrichtungen in der industriellen
Prozeßtechnik -- Teil 2: Energieversorgung
Conditions de fonctionnement pour les matériels de mesure et commande dans les
processus industriels -- Partie 2: Alimentation
Ta slovenski standard je istoveten z: EN 60654-2:1997
ICS:
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

NORME
CEI
INTERNATIONALE IEC
654-2
INTERNATIONAL
Première édition
STANDARD
First edition
Conditions de fonctionnement pour
les matériels de mesure et commande
dans les processus industriels
Partie 2:
Alimentation
Operating conditions for industrial-process
measurement and control equipment
Part 2:
Power
all rights reserved
© CEI 1979 Droits de reproduction réservés—Copyright —
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CONTENTS
Page
FOREWORD - 5
PREFACE
Clause
1. Scope
2. Object 7
3. General
Electrical power classification 9
4.
4.1 Definitions
4.2 A.C. power supply
4.3 D.C. power supply 17
4.4 Transient power disturbances
4.5 Operating conditions related to reliability and continuity of the electrical power supply
5. Pneumatic power classification
5.1 Definitions 21
5.2 Operating characteristics
INTERNATIONAL ELECTROTECHNICAL COMMISSION
OPERATING CONDITIONS FOR INDUSTRIAL-PROCESS
MEASUREMENT AND CONTROL EQUIPMENT
Part 2: Power
FOREWORD
The formal decisions or agreements of the IEC on technical matters, prepared by Technical Committees on which all the
1)
National Committees having a special interest therein are represented, express, as nearly as possible, an international
consensus of opinion on the subjects dealt with.
2) They have the form of recommendations for international use and they are accepted by the National Committees in that
sense.
rnational unification, the IEC expresses the wish that all National Committees should adopt
3) In order to promote inte
the text of the I EC recommendation for their national rules in so far as national conditions will permit. Any divergence
between the IEC recommendation and the corresponding national rules should, as far as possible, be clearly indicated
in the latter.
PREFACE
This standard has been prepared by IEC Technical Committee No. 65: Industrial-process Measure-
ment and Control.
It forms Part 2 of IEC Publication 654.
The first draft was discussed at the meeting held in Munich in 1973. Further drafts were discussed at
the meetings held in Moscow in 1975 and in Budapest in 1976. As a result of this latter meeting, a draft,
Document 65(Central Office)13, was submitted to the National Committees for approval under the Six
Months' Rule in May 1977. Amendments, Document 65(Central Office)18, were submitted to the National
Committees for approval under the Two Months' Procedure in June 1978.
The following countries voted explicitly in favour of publication:
Austria Japan
Netherlands
Belgium
Romania
Bulgaria
South Africa (Republic of)
Canada
Spain
Czechoslovakia
Sweden
Denmark
Switzerland
France
Turkey
Hungary
Italy United Kingdom
The National Committees of Germany and Poland voted against the amendments circulated under the
Two Months' Procedure.
—7—
PROCESS
OPERATING CONDITIONS FOR INDUSTRIAL -
MEASUREMENT AND CONTROL EQUIPMENT
Part 2: Power
1. Scope
2 of the standard gives the limiting values for power received by land-based and off-shore
Part
industrial-process measurement and control systems or parts of systems, during operation.
Maintenance and repair conditions are not considered.
Operating conditions directly related to fire and explosion hazards and conditions related to
nuclear radiation are likewise not considered.
The influence quantities considered in this part are limited to those which may directly
affect the performance of process systems. Effects of the specific operating conditions on
personnel are not within the scope of this part. Only operating conditions as such are considered;
the resulting effects of these conditions on instrumentation are specifically excluded.
This part establishes limit values, or sets of limit values, for the operating conditions listed.
Other operating conditions, including those for which characteristics are difficult both to define and
to measure, and for which adequate standards are not known to exist, will be covered in other
publications. An example of an operating condition difficult to define is corrosive atmospheres,
which are difficult to classify due to the wide variety and concentration of corrosive substances
and combinations of substances which may be encountered.
No classifications are recommended for hydraulic power supplies. In most instances, a separate
hydraulic supply is provided for each operating unit, or for a small group of units. The characteristics
of the supply are engineered specifically to meet the requirements of the units being operated.
Certain types of pressure regulators derive their operating power from the pressure of the fluid.
Similarly, certain types of temperature regulators derive pressure for valve operation from thermal
expansion of the fluid in the temperature-sensing elements.
The power supply for this type of "self-operated" device is not considered within the scope
of this standard.
2. Object
2 of the standard is to provide users and suppliers of industrial-process
The object of Part
measurement and control systems and parts of such systems with a uniform listing and classification
of the listed operating conditions related to power.

-9—
This part is intended to serve as a basis for the preparation of comprehensive specifications for
the listed operating conditions by the user and by the instrument-maker.
One of the purposes of this part is to avoid problems which might result from neglecting the
consideration of specific operating conditions affecting the performance of systems and parts
of systems.
An additional purpose of this part is to aid the choice of specific limit values for use in the
development of test specifications for industrial-process measurement and control equipment.
3. General
Part 2 of the standard considers the specific operating conditions related to power received
4) and
by systems, or parts of systems. These conditions are listed for electric power (see Clause
pneumatic power (see Clause 5). Systems and parts of systems are rarely connected to power supply
. Power conditions for calibration and test purposes are generally specified
in storage or transport
of test specification. They are not within the scope of this standard.
as a part
While this method results in a large number of possible combinations of operating conditions,
it appears to represent the "real world", where predictable relations between types of operating
conditions do not exist.
The severity, of the various operating conditions is shown by limit values rather than by
means of average values. These values cover usual ranges of operating conditions. It is recognized
that extreme or special operating conditions exist where values are greater and/or less than the
stated values. To accommodate this situation, "special" categories for the operating conditions
are provided. Specifications for equipment to operate under "special" or extreme conditions are a
matter for negotiation between user and supplier.
Unless otherwise specified or indicated (e.g. transportation, seismic effects), the conditions
classified in this standard are meant to be permanent, and under these conditions the equipment
shall perform normally in accordance with the defined specifications taking into account the specified
power.
4. Electrical power classification
4.1 Definitions
For the purpose of this standard only, the following definitions of terms relating to electrical
energy supply are used :
— Power: the energy supplied to a system or elements of a system for process measurement and
control.
— Power source: the primary source, usually a.c. mains, from which the system's power is derived.
a separate unit which converts, regulates, rectifies, or otherwise modifies
— Power supply device:
the supply from the primary power source to provide power suitable for a system or elements
of a system for process measurement and control.

— 11 —
Power supply: power source or power supply device from which the industrial-process
measurement and control system or elements of the system receive the energy in order to be
able to operate.
Steady-state power conditions: are defined as conditions persisting for more than 0.2 s.
Transient power disturbances: are defined as disturbances, which have a duration of 0.2 s or less.
Power voltage: the voltage of the power supply as presented to an industrial-process measurement
and control system or elements of system.
Power frequency: the frequency of the power supply as presented to an industrial-process
measurement and control system or elements of the system.
Electrical energy for operation of systems may be provided by:
— direct connection to a single power source;
— connection to a power supply device, interposed between the power source and the system or
element of a system;
— auxiliary stand-by or back-up power supply which provides for operation of the system or
elements of the system in case of maintenance or failure of the main power supply.
In this standard, operating conditions relating to the electrical power supply are classified only
for steady-state conditions. Classification of operating conditions related to transient power
disturbances (disturbances with a duration of 0.2 s or less) are deferred. There appear to be no
pertinent national standards defining suitable classifications. There are serious difficulties in
defining and measuring transient conditions.
Extreme voltage variations are of particular concern with respect to short-time under-voltage
which may result in drop out of relay or equivalent circuits which may change control action,
and with respect to sustained over-voltage which may result in possible deterioration or actual
burn out of components.
In this standard, there is no classification based on the impedance of the power supply.
The effect of the power supply impedance is taken into account by its effect on the power voltage
under varying load conditions.
— Maximum voltages are the values which may occur under minimum-load conditions.
Minimum voltages
— are the values which may occur under full-load conditions.
Note. — This approach to power supply impedance is perhaps somewhat less than rigorous. However, it appears practicable.
The definition of effective impedance, particularly for a.c., is difficult and of questionable significance for the
purpose of system operation unless supported by information regarding the character of the load impedance.
The latter is beyond the scope of this standard.
4.2 A.C. power supply
The characteristics of the a.c. power supply are listed separately: voltage (see Sub-clause 4.2.1);
frequency (see Sub-clause 4.2.2) ; harmonic content (see Sub-clause 4.2.3) ; phase angle (for polyphase
supplies) (see Sub-clause 4.2.4); auxiliary supply switching time (for an auxiliary or back-up power
supply) (see Sub-clause 4.2.5).

13 —
Extreme variations in a.c. power supply characteristics beyond the specified values can be
experienced in field conditions. Power supply specifications for these conditions are a matter for
negotiation between user and supplier.
4.2.1 A.C. power voltage classes
Power voltages are classified in accordance with the percentage variation of the voltage from its
nominal value. Four sets of limit values are listed:
4.2.1.1 +1% Class a.c.1.
Class a.c.2.
4.2.1.2 + 10%
Class a.c. 3.
4.2.1.3 + 10% to —15%
4.2.1.4 + 15% to —20% Class a.c.4.
Special: a.c. power voltages do not conform to Sub-clauses 4.2.1.1, 4.2.1.2, 4.2.1.3 or 4.2.1.4 above.
Note. — A.C. voltages are in terms of r.m.s. values, measured at the point of supply to the equipment.
The a.c. power voltage variation includes the effect of the power supply impedance together with
variation of load (see Sub-clause 4.1).
4.2.2 A.C. power frequency
The frequency variation is stated in per cent deviation from the nominal value. Three sets of
limit values are listed:
4.2.2.1 +0.2%.
4.2.2.2 ± 1 %.
4.2.2.3 +5%.
Special: a.c. power frequency does not conform to Sub-clauses 4.2.2.1, 4.2.2.2 or 4.2.2.3 above.
4.2.3 Harmonic content of an a.c. power supply
For this standard, only voltages which are true harmonics (integral multiples of nominal
frequency) less than ten times nominal frequency are considered. For this standard, harmonic
content is defined as the percentage of the square root of the sum of the squares of the harmonic
voltages to the fundamental power supply frequency voltage (r.m.s.). Four sets of limit values are
listed :
4.2.3.1 Harmonic level less than 2%.
4.2.3.2 Harmonic level less than 5%.
4.2.3.3 Harmonic level less than 10%.
4.2.3.4 Harmonic level less than 20%.
Special : harmonic content does not conform to Sub-clauses 4.2.3.1, 4.2.3.2, 4.2.3.3 or 4.2.3
...