ISO 8625-4:2011

INTERNATIONAL ISO
STANDARD 8625-4
First edition
2011-10-15

Aerospace — Fluid systems —
Vocabulary —
Part 4:
General terms and definitions relating to
control/actuation systems
Aéronautique et espace — Systèmes de fluides — Vocabulaire —
Partie 4: Termes et définitions généraux relatifs aux systèmes de
commande/d'actionnement




Reference number
ISO 8625-4:2011(E)
©
ISO 2011

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ISO 8625-4:2011(E)

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ii © ISO 2011 – All rights reserved

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ISO 8625-4:2011(E)
Contents Page
Foreword . iv
Introduction . v
Scope . 1
Terms and definitions . 1
4.1  Control system classification . 1
4.2  Control system technology (control engineering) . 3
4.3  Control system performance (servomechanism) . 9

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ISO 8625-4:2011(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 8625-4 was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee
SC 10, Aerospace fluid systems and components.
ISO 8625 consists of the following parts, under the general title Aerospace — Fluid systems — Vocabulary:
 Part 1: General terms and definitions relating to pressure
 Part 2: General terms and definitions relating to flow
 Part 3: General terms and definitions relating to temperature
 Part 4: General terms and definitions relating to control/actuation systems
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ISO 8625-4:2011(E)
Introduction
ISO 8625 contains only those terms which can be applied to general equipment and systems. Terms which
are only used for specific applications and specific components are to be incorporated into the relevant
product specifications and product standards.
Terms and definitions for components and systems which are associated with other systems (such as
electromechanical actuation systems or electronic control units) are incorporated only on a very general basis,
provided they have direct interfaces with fluid systems.

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INTERNATIONAL STANDARD ISO 8625-4:2011(E)

Aerospace — Fluid systems — Vocabulary —
Part 4:
General terms a
...