SIST ISO 12238:2023

Pneumatic fluid power - Directional control valves - Measurement of shifting time

This document specifies test procedures for measuring the shifting times of electrically or pneumatically operated directional control valves.
It is applicable to monostable and bistable pneumatic directional control valves, with 2 or 3 position functions.

Transmissions pneumatiques - Distributeurs de commande directionnels - Mesure du temps de basculement

Le présent document spécifie les modes opératoires d’essai pour mesurer les temps de basculement des distributeurs de commande directionnels à commande électrique ou pneumatique.
Il est applicable aux distributeurs de commande directionnels monostables et bistables, avec 2 ou 3 positions de commutation.

Fluidna tehnika - Pnevmatika - Potni ventili - Merjenje odzivnega časa

General Information

• Status: Published
• Publication Date: 13-Mar-2023
• ICS: 23.100.50 - Control components
• Technical Committee: IHPV - Hydraulics and pneumatics
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 06-Mar-2023
• Due Date: 11-May-2023
• Completion Date: 14-Mar-2023
• Ref Project: ISO 12238:2023 - Pneumatic fluid power — Directional control valves — Measurement of shifting time

Relations

• Revises: SIST ISO 12238:2002 - Pneumatic fluid power -- Directional control valves -- Measurement of shifting time
• Effective Date: 23-Apr-2020

Standards Content (Sample)

SLOVENSKI STANDARD
SIST ISO 12238:2023
01-april-2023
Fluidna tehnika - Pnevmatika - Potni ventili - Merjenje odzivnega časa

Pneumatic fluid power - Directional control valves - Measurement of shifting time

Transmissions pneumatiques - Distributeurs de commande directionnels - Mesure du
temps de basculement
Ta slovenski standard je istoveten z: ISO 12238:2023
ICS:
23.100.50 Krmilni sestavni deli Control components
SIST ISO 12238:2023 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST ISO 12238:2023
---------------------- Page: 2 ----------------------
SIST ISO 12238:2023
INTERNATIONAL ISO
STANDARD 12238
Second edition
2023-02
Pneumatic fluid power — Directional
control valves — Measurement of
shifting time
Transmissions pneumatiques — Distributeurs de commande
directionnels — Mesure du temps de basculement
Reference number
ISO 12238:2023(E)
© ISO 2023
---------------------- Page: 3 ----------------------
SIST ISO 12238:2023
ISO 12238:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
© ISO 2023 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 12238:2023
ISO 12238:2023(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction .................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Symbols and abbreviated terms..........................................................................................................................................................2

5 Test equipment ......................................................................................................................................................................................................2

5.1 Basic test setup ...................................................................................................................................................................................... 2

5.2 Pressure measuring tubes ........................................................................................................................................................... 4

5.3 Pressure transducers ....................................................................................................................................................................... 5

5.4 Supply reservoir .................................................................................................................................................................................... 5

5.5 Control signal ........................................................................................................................................................................................... 5

5.6 Data recording system .................................................................................................................................................................... 5

6 Test accuracy ........................................................................................................................................................................................................... 8

7 Test procedure .......................................................................................................................................................................................................8

8 Data calculations ..............................................................................................................................................................................................10

9 Reporting of test data ..................................................................................................................................................................................11

10 Identification statement (reference to this document) ...........................................................................................11

Annex A (informative) Example of generated test data and values to be reported .......................................12

Annex B (informative) Measurement of shifting time into non-exhausting positions ...............................13

Bibliography .............................................................................................................................................................................................................................17

iii
© ISO 2023 – All rights reserved
---------------------- Page: 5 ----------------------
SIST ISO 12238:2023
ISO 12238:2023(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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

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. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 131, Fluid power systems, Subcommittee

SC 5, Control products and components.

This second edition cancels and replaces the first edition (ISO 12238:2001), which has been technically

revised.
The main changes are as follows:

— the Scope has been extended to include monostable and bistable valves with two or three shifting

position functions;

— extensions to the concept of shifting time measurement by addition of specifications for tests when

shifting into non-exhausting positions have been added;

— consistency with other International Standards such as the ISO 6358 series has been improved;

— references to state-of-the-art test equipment and procedures have been updated.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
© ISO 2023 – All rights reserved
---------------------- Page: 6 ----------------------
SIST ISO 12238:2023
ISO 12238:2023(E)
Introduction

In pneumatic fluid power systems, power is transmitted and controlled through a gas under pressure

circulating within a circuit. In some applications, the designer of a fluid power system needs to know

the time required to cause the valving elements in a pneumatic directional control valve to move and to

generate an output signal.
© ISO 2023 – All rights reserved
---------------------- Page: 7 ----------------------
SIST ISO 12238:2023
---------------------- Page: 8 ----------------------
SIST ISO 12238:2023
INTERNATIONAL STANDARD ISO 12238:2023(E)
Pneumatic fluid power — Directional control valves —
Measurement of shifting time
1 Scope

This document specifies test procedures for measuring the shifting times of electrically or pneumatically

operated directional control valves.

It is applicable to monostable and bistable pneumatic directional control valves, with 2 or 3 position

functions.
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.

ISO 80000-1, Quantities and units — Part 1: General

ISO 1219-1, Fluid power systems and components — Graphical symbols and circuit diagrams — Part 1:

Graphical symbols for conventional use and data-processing applications
ISO 5598, Fluid power systems and components — Vocabulary

ISO 6358-1, Pneumatic fluid power — Determination of flow-rate characteristics of components using

compressible fluids — Part 1: General rules and test methods for steady-state flow

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 5598 and the following apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
shifting time

time lapse measured from a change in the control signal (electrical or pneumatic) until the time at

which the pressure in the associated outlet port changes by a specified amount

Note 1 to entry: Depending on the type of valve, shifting on-time or shifting off-time can mean shifting into

exhausting or non-exhausting positions. For ISO 12238 the terms "shifting time (exhaust)" and "shifting time

(fill)" are therefore used as well as the phrase "shifting time into non-exhausting positions". Depending on the

valve type, the corresponding shifting on-time or shifting off-time is then obtained for the specifications in the

catalog.
3.2
shifting on-time
shifting time when the control signal is applied
3.3
shifting off-time
shifting time when the control signal is removed
© ISO 2023 – All rights reserved
---------------------- Page: 9 ----------------------
SIST ISO 12238:2023
ISO 12238:2023(E)
3.4
shifting time (exhaust)

shifting time for shifts into a position where the working port is exhausting, obtained for a change of

10 % in the outlet pressure
3.5
shifting time (fill)

shifting time for shifts into a position where the working port is filling a connected component or

system, obtained for a change of 10 % in the outlet pressure
3.6
shifting time (non-exhausting)
shifting time for shifts into a position where the working port is closed
4 Symbols and abbreviated terms

4.1 The symbols and units for parameters used in this document shall be as given in Table 1 and shall

be in accordance with ISO 80000-1.
Table 1 — Symbols and units
Symbol Parameter Unit
t base for time measurement ms
t shifting time (exhaust) ms
t shifting time (fill) ms
t shifting time (non-exhausting) ms

4.2 Graphic symbols used in this document shall conform to the requirements of ISO 1219-1.

5 Test equipment
5.1 Basic test setup
The basic test equipment shall be as shown in Figures 1 and 2.

When shifting into a non-exhausting valve position, the shifting time cannot be measured due to a lack

of a pressure drop. For measuring the shifting time of shifts into non-exhausting valve positions (e.g.

2/2 or 5/3 closed centre position), a throttle valve and a flow sensor shall be used (also see key 9 and

key 10 in Figures 1 and 2).
© ISO 2023 – All rights reserved
---------------------- Page: 10 ----------------------
SIST ISO 12238:2023
ISO 12238:2023(E)
Key
1 control signal
2 pressure transducers
3 output recording device(s)
4 valve under test
5 pressure measuring tube in accordance with ISO 6358-1
6 shut-off valve (optional)
7 thermometer
8 supply reservoir
9 throttle valve (only for non-exhausting valve positions)
10 flow sensor (only for non-exhausting valve positions)
Figure 1 — Test equipment for electrically-operated valves

For pneumatically operated valves (Figure 2), the sonic conductance C, as defined in ISO 6358-1, of the

control valve (key 1) shall be larger than the sonic conductance C of the pilot port of the valve under test

(key 4). The connection between control valve (key 1) and the pressure measuring tube (key 5) at the

pilot port of the valve under test should be as short as possible.
© ISO 2023 – All rights reserved
---------------------- Page: 11 ----------------------
SIST ISO 12238:2023
ISO 12238:2023(E)
Key
1 control valve (to generate control signal)
2 pressure transducers
3 output recording device(s)
4 valve under test
5 pressure measuring tube in accordance with ISO 6358-1
6 shut-off valve (optional)
7 thermometer
8 supply reservoir
9 throttle valve (only for non-exhausting valve positions)
10 flow sensor (only for non-exhausting valve positions)
Figure 2 — Test equipment for pneumatically-operated valves
5.2 Pressure measuring tubes

5.2.1 A straight pressure measuring tube should be threaded into the valve inlet port, as well as into

the valve pilot port when applicable, and shall be made in accordance with ISO 6358-1.

The test setup from ISO 6358-1 requires transition connectors for the flow measurement. These reduce

the speed of the flow in the measuring tube. This is not necessary for shifting time measurement and

the transition connectors are not required for this test. Nevertheless, the transition connectors from

ISO 6358-1 may be used for the tests according to ISO 12238.

5.2.2 Select and attach pressure measuring tubes to the test valve whose threads correspond to each

port size of the valve flow path, and to the valve pilot port when applicable.
© ISO 2023 – All rights reserved
---------------------- Page: 12 ----------------------
SIST ISO 12238:2023
ISO 12238:2023(E)
5.3 Pressure transducers

5.3.1 Install a pressure transducer into the inlet pressure measuring tube. Also install a pressure

transducer directly into each outlet port to be tested, to have an outlet volume as small as possible. All

untested outlet ports shall be plugged.

5.3.2 When a pneumatically-operated valve is tested, mount an additional control pressure

transducer into the pilot pressure measuring tube.
5.4 Supply reservoir

5.4.1 Use a supply reservoir of sufficient capacity so that the pressure drop caused by the piping and

measured in the pressure measuring tube at the inlet port during the test does not exceed 3 % of the

...

ISO/TC 131/SC 5
Date: 2022-06-0130
ISO/DISFDIS 12238:2022(E)
TC 131/SC 5/WG 3
Secretariat: ANSI
Pneumatic fluid power — Directional control valves — Measurement of shifting
time
Transmissions pneumatiques — Distributeurs de commande directionnels — Mesure du
temps de commutation
© ISO 2022 – All rights reserved
---------------------- Page: 1 ----------------------
ISO/FDIS 12238:2022(E)
COPYRIGHT PROTECTED DOCUMENT

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or

utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,

or posting on the internet or an intranet, without prior written permission. Permission can be

requested from either ISO at the address below or ISO’s member body in the country of the

requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
[e-mail]
www.iso.org
ii © ISO 2022 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 12238:2022(E)
Contents Page

Foreword ......................................................................................................................................................................... iv

Introduction ..................................................................................................................................................................... v

1 Scope .................................................................................................................................................................... 1

2 Normative references .................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................... 1

4 Symbols and abbreviated terms ................................................................................................................. 2

5 Test equipment ................................................................................................................................................. 2

5.1 Basic test setup ................................................................................................................................................. 2

5.2 Pressure measuring tubes ............................................................................................................................ 5

5.3 Pressure transducers ..................................................................................................................................... 5

5.4 Supply reservoir ............................................................................................................................................... 5

5.5 Control signal .................................................................................................................................................... 6

5.6 Data recording system ................................................................................................................................... 6

6 Test accuracy ..................................................................................................................................................... 8

7 Test procedure ................................................................................................................................................. 8

7.1 An overview of test procedures is given in tables 3 and 4 ................................................................ 8

8 Data calculations ........................................................................................................................................... 10

9 Reporting of test data .................................................................................................................................. 11

10 Identification statement (reference to this document) .................................................................. 11

Annex A (informative) Example of generated test data and values to be reported ........................... 12

Annex B (informative) Measurement of shifting time into non-exhausting positions ..................... 13

Bibliography ................................................................................................................................................................. 16

© ISO 20212022 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/FDIS 12238:2022(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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

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. Details of any

patent rights identified during the development of the document will be in the Introduction and/or on

the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the World

Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 131, Fluid power systems, Subcommittee

SC 5, Control products and components.

This second edition cancels and replaces the first edition (ISO 12238:2001), which has been technically

revised.
The main changes are as follows:

— the Scope has been extended to include mono-monostable and bistable valves with two or three

shifting position functions;

— extensions to the concept of shifting time measurement by addition of specifications for tests when

shifting into non-exhausting positions have been added;

— consistency with other International Standards such as the ISO 6358 series has been improved;

— references to state-of-the-art test equipment and procedures have been updated.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
iv © ISO 2022 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/FDIS 12238:2022(E)
Introduction

In pneumatic fluid power systems, power is transmitted and controlled through a gas under pressure

circulating within a circuit. In some applications, the designer of a fluid power system needs to know the

time required to cause the valving elements in a pneumatic directional control valve to move and to

generate an output signal.
© ISO 20212022 – All rights reserved v
---------------------- Page: 5 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 12238:2022(E)
Pneumatic fluid power — Directional control valves —
Measurement of shifting time
1 Scope

This document specifies test procedures for measuring the shifting times of electrically or pneumatically

operated directional control valves.

It is applicable to monostable and bistable pneumatic directional control valves, with 2 or 3 position

functions.
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.

ISO 80000--1, Quantities and units — Part 1: General

ISO 1219-1, Fluid power systems and components — Graphical symbols and circuit diagrams — Part 1:

Graphical symbols for conventional use and data-processing applications
ISO 5598, Fluid power systems and components — Vocabulary

ISO 6358-1, Pneumatic fluid power — Determination of flow-rate characteristics of components using

compressible fluids — Part 1: General rules and test methods for steady-state flow

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 5598 and the following apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
shifting time (exhaust)

shifting time for shifts into a position where the working port is exhausting, obtained for a change of 10 %

in the outlet pressure
3.2
shifting time (fill)

shifting time for shifts into a position where the working port is filling a connected component or system,

obtained for a change of 10 % in the outlet pressure
3.3
shifting time (non-exhausting)
shifting time for shifts into a position where the working port is closed.
© ISO 2022 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO/FDIS 12238:2022(E)
4 Symbols and abbreviated terms

4.1 The symbols and units for parameters used in this document shall be as given in Table 1 and shall be

in accordance with ISO 80000-1.
Table 1 — Symbols and units
Symbol Parameter Unit
t base for time measurement ms
tE shifting time (exhaust) ms
t shifting time (fill) ms
tNE shifting time into non-exhausting position (exhaust) ms

4.2 Graphic symbols used in this document shall conform to the requirements of ISO 1219-1.

5 Test equipment
5.1 Basic test setup
The basic test equipment shall be as shown in Figures 1 and 2.

When shifting into a non-exhausting valve position the shifting time cannot be measured due to a lack of

a pressure drop. For measuring the shifting time of shifts into non-exhausting valve positions (e.g. 2/2 or

5/3 closed centre position) a throttle valve and a flow sensor shall be used (also see key 9 and key 10 in

Figures 1 and 2).
2 © ISO 2022 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/FDIS 12238:2022(E)
Key
1 control signal
2 pressure transducers
3 output recording device(s)
4 valve under test
5 pressure measuring tube in accordance with ISO 6358-1
6 shut-off valve (optional)
7 thermometer
8 supply reservoir
9 throttle valve (only for non-exhausting valve positions)
10 flow sensor (only for non-exhausting valve positions)
Figure 1 — Test equipment for electrically-operated valves

For pneumatically operated valves (Figure 2) the sonic conductance C as defined in ISO 6358-1 of the

control valve (key 1) shall be larger than the C- value of the pilot port of the valve under test (key 4). The

connection between control valve (key 1) and the pressure measuring tube (key 5) at the pilot port of the

valve under test should be as short as possible.
© ISO 2022 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO/FDIS 12238:2022(E)
Key
1 control valve (to generate control signal)
4 © ISO 2022 – All rights reserved
---------------------- Page: 9 ----------------------
ISO/FDIS 12238:2022(E)
2 pressure transducers
3 output recording device(s)
4 valve under test
5 pressure measuring tube in accordance with ISO 6358-1
6 shut-off valve (optional)
7 thermometer
8 supply reservoir
9 throttle valve (only for non-exhausting valve positions)
10 flow sensor (only for non-exhausting valve positions)
Figure 2 — Test equipment for pneumatically-operated valves
5.2 Pressure measuring tubes

5.2.1 A straight pressure measuring tube should be threaded into the valve inlet port, as well as into

the valve pilot port when applicable, and shall be made in accordance with ISO 6358-1.

The test setup from ISO 6358-1 requires transition connectors for the flow measurement. These reduce

the speed of the flow in the measuring tube. This is not necessary for shifting time measurement and the

transition connectors are not required for this test. Nevertheless, the transition connectors from

ISO 6358-1 may be used for the tests according to ISO 12238.

5.2.2 Select and attach pressure measuring tubes to the test valve whose threads correspond to each

port size of the valve flow path, and to the valve pilot port when applicable.
5.3 Pressure transducers

5.3.1 Install a pressure transducer into the inlet pressure measuring tube. Also install a pressure

transducer directly into each outlet port to be tested, to have an outlet volume as small as possible. All

untested outlet ports shall be plugged.

5.3.2 When a pneumatically-operated valve is tested, mount an additional control pressure transducer

into the pilot pressure measuring tube.
5.4 Supply reservoir

5.4.1 Use a supply reservoir of sufficient capacity so that the pressure drop caused by the piping and

measured in the pressure measuring tube at the inlet port during the test does not exceed 3 % of the

supply pressure. A larger pressure drop is permissible but will increase the shifting time and result in a

less favourable rating for the product under test. Connections from the supply reservoir should be several

times larger than the pressure measuring tube and as short as possible, to minimize the pressure drop.

5.4.2 Use a supply reservoir that allows measuring the internal air temperature of the reservoir.

Maintain the supply reservoir temperature between 18 °C and 30 °C.

5.4.3 Locate the optional shut-off valve, and the control valve when applicable, as close as possible to

the reservoir outlet. Use a valve whose sonic conductancewith a C as defined in ISO 6358-1 isvalue larger

than that of the pressure measuring tube, because a smaller valve can restrict the flow and increase the

shifting time.
© ISO 2022 – All rights reserved 5
---------------------- Page: 10 ----------------------
ISO/FDIS 12238:2022(E)
5.5 Control signal

5.5.1 For solenoid pilot-operated valves or pneumatically-operated valves, maintain the external pilot

supply pressure at either the test pressure supplied to the valve or the maximum permitted pilot supply

pressure, whichever is less.

5.5.2 For AC solenoid-operated valves, generate the control signal with a trigger device set to trigger at

the zero-voltage crossover point. Maintain voltage to within ±2 % of the rated voltage.

5.5.3 For DC
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 12238
ISO/TC 131/SC 5
Pneumatic fluid power — Directional
Secretariat: AFNOR
control valves — Measurement of
Voting begins on:
2022-07-15 shifting time
Voting terminates on:
Transmissions pneumatiques — Distributeurs de commande
2022-09-09
directionnels — Mesure du temps de commutation
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 12238:2022(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. © ISO 2022
---------------------- Page: 1 ----------------------
ISO/FDIS 12238:2022(E)
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 12238
ISO/TC 131/SC 5
Pneumatic fluid power — Directional
Secretariat: AFNOR
control valves — Measurement of
Voting begins on:
shifting time
Voting terminates on:
Transmissions pneumatiques — Distributeurs de commande
directionnels — Mesure du temps de commutation
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
RECIPIENTS OF THIS DRAFT ARE INVITED TO
ISO copyright office
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
CP 401 • Ch. de Blandonnet 8
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
CH-1214 Vernier, Geneva
DOCUMENTATION.
Phone: [phone]
IN ADDITION TO THEIR EVALUATION AS
Reference number
Email: [e-mail]
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 12238:2022(E)
Website: www.iso.org
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
Published in Switzerland
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
© ISO 2022 – All rights reserved
NATIONAL REGULATIONS. © ISO 2022
---------------------- Page: 2 ----------------------
ISO/FDIS 12238:2022(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction .................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Symbols and abbreviated terms..........................................................................................................................................................2

5 Test equipment ......................................................................................................................................................................................................2

5.1 Basic test setup ...................................................................................................................................................................................... 2

5.2 Pressure measuring tubes ........................................................................................................................................................... 4

5.3 Pressure transducers ....................................................................................................................................................................... 5

5.4 Supply reservoir .................................................................................................................................................................................... 5

5.5 Control signal ........................................................................................................................................................................................... 5

5.6 Data recording system .................................................................................................................................................................... 5

6 Test accuracy ........................................................................................................................................................................................................... 8

7 Test procedure .......................................................................................................................................................................................................8

7.1 An overview of test procedures is given in tables 3 and 4 .............................................................................. 8

8 Data calculations ..............................................................................................................................................................................................10

9 Reporting of test data ..................................................................................................................................................................................11

10 Identification statement (reference to this document) ...........................................................................................11

Annex A (informative) Example of generated test data and values to be reported .......................................12

Annex B (informative) Measurement of shifting time into non-exhausting positions ...............................13

Bibliography .............................................................................................................................................................................................................................16

iii
© ISO 2022 – All rights reserved
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ISO/FDIS 12238:2022(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 non­governmental, 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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

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. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/

iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 131, Fluid power systems, Subcommittee

SC 5, Control products and components.

This second edition cancels and replaces the first edition (ISO 12238:2001), which has been technically

revised.
The main changes are as follows:

— the Scope has been extended to include monostable and bistable valves with two or three shifting

position functions;

— extensions to the concept of shifting time measurement by addition of specifications for tests when

shifting into non-exhausting positions have been added;

— consistency with other International Standards such as the ISO 6358 series has been improved;

— references to state-of-the-art test equipment and procedures have been updated.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
© ISO 2022 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/FDIS 12238:2022(E)
Introduction

In pneumatic fluid power systems, power is transmitted and controlled through a gas under pressure

circulating within a circuit. In some applications, the designer of a fluid power system needs to know

the time required to cause the valving elements in a pneumatic directional control valve to move and to

generate an output signal.
© ISO 2022 – All rights reserved
---------------------- Page: 5 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 12238:2022(E)
Pneumatic fluid power — Directional control valves —
Measurement of shifting time
1 Scope

This document specifies test procedures for measuring the shifting times of electrically or pneumatically

operated directional control valves.

It is applicable to monostable and bistable pneumatic directional control valves, with 2 or 3 position

functions.
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.

ISO 80000­1, Quantities and units — Part 1: General

ISO 1219­1, Fluid power systems and components — Graphical symbols and circuit diagrams — Part 1:

Graphical symbols for conventional use and data-processing applications
ISO 5598, Fluid power systems and components — Vocabulary

ISO 6358­1, Pneumatic fluid power — Determination of flow-rate characteristics of components using

compressible fluids — Part 1: General rules and test methods for steady-state flow

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 5598 and the following apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
shifting time (exhaust)

shifting time for shifts into a position where the working port is exhausting, obtained for a change of

10 % in the outlet pressure
3.2
shifting time (fill)

shifting time for shifts into a position where the working port is filling a connected component or

system, obtained for a change of 10 % in the outlet pressure
3.3
shifting time (non-exhausting)
shifting time for shifts into a position where the working port is closed.
© ISO 2022 – All rights reserved
---------------------- Page: 6 ----------------------
ISO/FDIS 12238:2022(E)
4 Symbols and abbreviated terms

4.1 The symbols and units for parameters used in this document shall be as given in Table 1 and shall

be in accordance with ISO 80000­1.
Table 1 — Symbols and units
Symbol Parameter Unit
t base for time measurement ms
t shifting time (exhaust) ms
t shifting time (fill) ms
t shifting time into non-exhausting position (exhaust) ms

4.2 Graphic symbols used in this document shall conform to the requirements of ISO 1219-1.

5 Test equipment
5.1 Basic test setup
The basic test equipment shall be as shown in Figures 1 and 2.

When shifting into a non-exhausting valve position the shifting time cannot be measured due to a lack

of a pressure drop. For measuring the shifting time of shifts into non-exhausting valve positions (e.g.

2/2 or 5/3 closed centre position) a throttle valve and a flow sensor shall be used (also see key 9 and

key 10 in Figures 1 and 2).
© ISO 2022 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/FDIS 12238:2022(E)
Key
1 control signal
2 pressure transducers
3 output recording device(s)
4 valve under test
5 pressure measuring tube in accordance with ISO 6358­1
6 shut­off valve (optional)
7 thermometer
8 supply reservoir
9 throttle valve (only for non-exhausting valve positions)
10 flow sensor (only for non-exhausting valve positions)
Figure 1 — Test equipment for electrically-operated valves

For pneumatically operated valves (Figure 2) the sonic conductance C as defined in ISO 6358-1 of the

control valve (key 1) shall be larger than the C- value of the pilot port of the valve under test (key 4).

The connection between control valve (key 1) and the pressure measuring tube (key 5) at the pilot port

of the valve under test should be as short as possible.
© ISO 2022 – All rights reserved
---------------------- Page: 8 ----------------------
ISO/FDIS 12238:2022(E)
Key
1 control valve (to generate control signal)
2 pressure transducers
3 output recording device(s)
4 valve under test
5 pressure measuring tube in accordance with ISO 6358­1
6 shut­off valve (optional)
7 thermometer
8 supply reservoir
9 throttle valve (only for non-exhausting valve positions)
10 flow sensor (only for non-exhausting valve positions)
Figure 2 — Test equipment for pneumatically-operated valves
5.2 Pressure measuring tubes

5.2.1 A straight pressure measuring tube should be threaded into the valve inlet port, as well as into

the valve pilot port when applicable, and shall be made in accordance with ISO 6358­1.

The test setup from ISO 6358-1 requires transition connectors for the flow measurement. These reduce

the speed of the flow in the measuring tube. This is not necessary for shifting time measurement and

the transition connectors are not required for this test. Nevertheless, the transition connectors from

ISO 6358-1 may be used for the tests according to ISO 12238.

5.2.2 Select and attach pressure measuring tubes to the test valve whose threads correspond to each

port size of the valve flow path, and to the valve pilot port when applicable.
© ISO 2022 – All rights reserved
---------------------- Page: 9 ----------------------
ISO/FDIS 12238:2022(E)
5.3 Pressure transducers

5.3.1 Install a pressure transducer into the inlet pressure measuring tube. Also install a pressure

transducer directly into each outlet port to be tested, to have an outlet volume as small as possible. All

untested outlet ports shall be plugged.

5.3.2 When a pneumatically-operated valve is tested, mount an additional control pressure

transducer into the pilot pressure measuring tube.
5.4 Supply reservoir

5.4.1 Use a supply reservoir of sufficient capacity so that the pressure drop caused by the piping and

measured in the pressure measuring tube at the inlet port during the test does not exceed 3 % of the

supply pressure. A larger pressure drop is permissible but will increase the shifting time and result

in a less favourable rating for the product under test. Connections
...

PROJET
NORME ISO/FDIS
FINAL
INTERNATIONALE 12238
ISO/TC 131/SC 5
Transmissions pneumatiques —
Secrétariat: AFNOR
Distributeurs de commande
Début de vote:
2022-07-15 directionnels — Mesure du temps de
commutation
Vote clos le:
2022-09-09
Pneumatic fluid power — Directional control valves — Measurement
of shifting time
LES DESTINATAIRES DU PRÉSENT PROJET SONT
INVITÉS À PRÉSENTER, AVEC LEURS OBSER-
VATIONS, NOTIFICATION DES DROITS DE PRO-
PRIÉTÉ DONT ILS AURAIENT ÉVENTUELLEMENT
CONNAISSANCE ET À FOURNIR UNE DOCUMEN-
TATION EXPLICATIVE.
OUTRE LE FAIT D’ÊTRE EXAMINÉS POUR
ÉTABLIR S’ILS SONT ACCEPTABLES À DES FINS
INDUSTRIELLES, TECHNOLOGIQUES ET COM-
Numéro de référence
MERCIALES, AINSI QUE DU POINT DE VUE
ISO/FDIS 12238:2022(F)
DES UTILISATEURS, LES PROJETS DE NORMES
INTERNATIONALES DOIVENT PARFOIS ÊTRE
CONSIDÉRÉS DU POINT DE VUE DE LEUR POSSI-
BILITÉ DE DEVENIR DES NORMES POUVANT
SERVIR DE RÉFÉRENCE DANS LA RÉGLEMENTA-
TION NATIONALE. © ISO 2022
---------------------- Page: 1 ----------------------
ISO/FDIS 12238:2022(F)
PROJET
NORME ISO/FDIS
FINAL
INTERNATIONALE 12238
ISO/TC 131/SC 5
Transmissions pneumatiques —
Secrétariat: AFNOR
Distributeurs de commande
Début de vote:
2022-07-15 directionnels — Mesure du temps de
commutation
Vote clos le:
2022-09-09
Pneumatic fluid power — Directional control valves — Measurement
of shifting time
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2022

Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette

publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,

LES DESTINATAIRES DU PRÉSENT PROJET SONT

y compris la photocopie, ou la diffusion sur l’internet ou sur un intranet, sans autorisation écrite préalable. Une autorisation peut

INVITÉS À PRÉSENTER, AVEC LEURS OBSER-
VATIONS, NOTIFICATION DES DROITS DE PRO-

être demandée à l’ISO à l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.

PRIÉTÉ DONT ILS AURAIENT ÉVENTUELLEMENT
ISO copyright office
CONNAISSANCE ET À FOURNIR UNE DOCUMEN-
TATION EXPLICATIVE.
Case postale 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Genève OUTRE LE FAIT D’ÊTRE EXAMINÉS POUR
ÉTABLIR S’ILS SONT ACCEPTABLES À DES FINS
Tél.: [phone]
INDUSTRIELLES, TECHNOLOGIQUES ET COM-
Numéro de référence
E-mail: [e-mail]
MERCIALES, AINSI QUE DU POINT DE VUE
ISO/FDIS 12238:2022(F)
Web: www.iso.org
DES UTILISATEURS, LES PROJETS DE NORMES
INTERNATIONALES DOIVENT PARFOIS ÊTRE
Publié en Suisse
CONSIDÉRÉS DU POINT DE VUE DE LEUR POSSI-
BILITÉ DE DEVENIR DES NORMES POUVANT
SERVIR DE RÉFÉRENCE DANS LA RÉGLEMENTA-
© ISO 2022 – Tous droits réservés
TION NATIONALE. © ISO 2022
---------------------- Page: 2 ----------------------
ISO/FDIS 12238:2022(F)
Sommaire Page

Avant-propos .............................................................................................................................................................................................................................iv

Introduction .................................................................................................................................................................................................................................v

1 Domaine d’application ................................................................................................................................................................................... 1

2 Références normatives ..................................................................................................................................................................................1

3 Termes et définitions ...................................................................................................................................................................................... 1

4 Symboles et abréviations ............................................................................................................................................................................2

5 Équipement d’essai ............................................................................................................................................................................................ 2

5.1 Installation d’essai de base .......................................................................................................................................................... 2

5.2 Tubes de mesure de pression ..................................................................................................................................................... 4

5.3 Capteurs de pression ......................................................................................................................................................................... 5

5.4 Réservoir d’alimentation ............................................................................................................................................................... 5

5.5 Signal de commande .......................................................................................................................................................................... 5

5.6 Système d’enregistrement des données ........................................................................................................................... 6

6 Exactitude d’essai................................................................................................................................................................................................8

7 Mode opératoire d’essai ............................................................................................................................................................................... 8

8 Calculs de données ..........................................................................................................................................................................................11

9 Collecte des données d’essai .................................................................................................................................................................11

10 Phrase d’identification (référence au présent document) ...................................................................................12

Annexe A (informative) Exemple de données générées et de valeurs à enregistrer .....................................13

Annexe B (informative) Mesurage du temps de commutation dans des positions fermées..................14

Bibliographie ...........................................................................................................................................................................................................................19

iii
© ISO 2022 – Tous droits réservés
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ISO/FDIS 12238:2022(F)
Avant-propos

L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes

nationaux de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est

en général confiée aux comités techniques de l’ISO. Chaque comité membre intéressé par une étude

a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,

gouvernementales et non gouvernementales, en liaison avec l’ISO participent également aux travaux.

L’ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui

concerne la normalisation électrotechnique.

Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont

décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier, de prendre note des différents

critères d’approbation requis pour les différents types de documents ISO. Le présent document a été

rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2 (voir www.

iso.org/directives).

L’attention est attirée sur le fait que certains des éléments du présent document peuvent faire l’objet de

droits de propriété intellectuelle ou de droits analogues. L’ISO ne saurait être tenue pour responsable

de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant

les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de

l’élaboration du document sont indiqués dans l’Introduction et/ou dans la liste des déclarations de

brevets reçues par l’ISO (voir www.iso.org/brevets).

Les appellations commerciales éventuellement mentionnées dans le présent document sont données

pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un

engagement.

Pour une explication de la nature volontaire des normes, la signification des termes et expressions

spécifiques de l’ISO liés à l’évaluation de la conformité, ou pour toute information au sujet de l’adhésion

de l’ISO aux principes de l’Organisation mondiale du commerce (OMC) concernant les obstacles

techniques au commerce (OTC), voir le lien suivant : www.iso.org/iso/fr/avant-propos.html.

Le présent document a été élaboré par le comité technique ISO/TC 131, Transmissions hydrauliques et

pneumatiques, sous-comité SC 5, Appareils de régulation et de distribution et leurs composants.

Cette deuxième édition annule et remplace la première édition (ISO 12238:2001), qui a fait l’objet d’une

révision technique.

Les principales modifications par rapport à l’édition précédente sont les suivantes :

— extension du domaine d’application aux distributeurs monostables et bistables avec deux ou trois

positions de commutation ;

— extension du concept de mesure du temps de commutation en ajoutant des spécifications pour les

essais en cas de commutation dans des positions fermées;

— amélioration de la cohérence avec d’autres normes, telle que la série ISO 6358 ;

— mises à jour pour refléter l’état de l’art au niveau de l’équipement et des modes opératoires.

Il convient que l’utilisateur adresse tout retour d’information ou toute question concernant le présent

document à l’organisme national de normalisation de son pays. Une liste exhaustive desdits organismes

se trouve à l’adresse www.iso.org/fr/members.html.
© ISO 2022 – Tous droits réservés
---------------------- Page: 4 ----------------------
ISO/FDIS 12238:2022(F)
Introduction

Dans les systèmes de transmissions pneumatiques, l’énergie est transmise et contrôlée par

l’intermédiaire d’un air comprimé circulant dans un circuit. Dans certaines applications, le concepteur

d’un système de transmissions pneumatiques a besoin de connaître le temps requis pour provoquer le

mouvement des éléments de manœuvre de distribution dans un distributeur de commande directionnel

pneumatique et pour engendrer un signal de sortie.
© ISO 2022 – Tous droits réservés
---------------------- Page: 5 ----------------------
PROJET FINAL DE NORME INTERNATIONALE ISO/FDIS 12238:2022(F)
Transmissions pneumatiques — Distributeurs de
commande directionnels — Mesure du temps de
commutation
1 Domaine d’application

Le présent document spécifie les modes opératoires d’essai pour mesurer les temps de commutation

des distributeurs de commande directionnels à commande électrique ou pneumatique.

Il est applicable aux distributeurs de commande directionnels monostables et bistables, avec 2 ou 3

positions de commutation.
2 Références normatives

Les documents suivants sont cités dans le texte de sorte qu’ils constituent, pour tout ou partie de leur

contenu, des exigences du présent document. Pour les références datées, seule l'édition citée s'applique.

Pour les références non datées, la dernière édition du document de référence s'applique (y compris les

éventuels amendements).
ISO 80000-1, Grandeurs et unités — Partie 1 : Généralités

ISO 1219-1, Transmissions hydrauliques et pneumatiques — Symboles graphiques et schémas de circuit —

Partie 1: Symboles graphiques en emploi conventionnel et informatisé
ISO 5598, Transmissions hydrauliques et pneumatiques — Vocabulaire

ISO 6358-1, Transmissions pneumatiques — Détermination des caractéristiques de débit des composants

traversés par un fluide compressible — Partie 1: Règles générales et méthodes d'essai en régime stationnaire

3 Termes et définitions

Pour les besoins du présent document, les termes et les définitions de l’ISO 5598 ainsi que les suivants,

s’appliquent.

L'ISO et l'IEC tiennent à jour des bases de données terminologiques destinées à être utilisées en

normalisation, consultables aux adresses suivantes :

— ISO Online browsing platform : disponible à l'adresse https:// www .iso .org/ obp

— IEC Electropedia : disponible à l'adresse https:// www .electropedia .org/
3.1
temps de commutation (échappement)

temps de commutation correspondant aux commutations dans une position où l’orifice d’utilisation est

en cours d’échappement, obtenue pour une variation de 10 % de la pression de sortie

3.2
temps de commutation (alimentation)

temps de commutation correspondant aux commutations dans une position où l’orifice d’utilisation est

en cours de remplissage d’un composant ou d’un système raccordé, obtenue pour une variation de 10 %

de la pression de sortie
© ISO 2022 – Tous droits réservés
---------------------- Page: 6 ----------------------
ISO/FDIS 12238:2022(F)
3.3
temps de commutation (non-échappement)

temps de commutation correspondant aux commutations dans une position où l’orifice d’utilisation est

fermé
4 Symboles et abréviations

4.1 Les symboles et unités des paramètres utilisés dans le présent document doivent être tels que

donnés dans le Tableau 1 et doivent être conforme à l’ISO 80000-1.
Tableau 1 — Symboles et unités
Unité (conformément à
Symbole Paramètre
l’ISO 1000)
t base du temps de mesure ms
t temps de commutation (échappement) ms
t temps de commutation (alimentation) ms
t temps de commutation dans une position fermée (échappement) ms

4.2 Les symboles graphiques utilisés dans le présent document sont conformes aux exigences de

l’ISO 1219-1.
5 Équipement d’essai
5.1 Installation d’essai de base
L’équipement d’essai de base doit être tel que représenté aux Figures 1 et 2.

Lors de la commutation dans une position fermée, le temps de commutation ne peut pas être mesuré en

raison de l’absence de perte de charge. Pour mesurer le temps de commutation pour les commutations

dans des positions fermées (par exemple position centrale fermée 2/2 ou 5/3), un limiteur de débit et

un capteur de débit doivent être utilisés (voir aussi la légende 9 et la légende 10 sur les Figures 1 et 2).

© ISO 2022 – Tous droits réservés
---------------------- Page: 7 ----------------------
ISO/FDIS 12238:2022(F)
Légende
1 signal de commande
2 capteurs de pression
3 dispositif(s) d’enregistrement de sortie
4 distributeur soumis à essai
5 tube de mesure de pression en conformité avec l’ISO 6358-1
6 robinet d’isolement (facultatif)
7 thermomètre
8 réservoir d’alimentation
9 limiteur de débit (uniquement pour les positions fermées)
10 capteur de débit (uniquement pour les positions fermées)
Figure 1 — Équipement d’essai pour distributeurs à commande électrique

Pour les distributeurs à commande pneumatique (Figure 2), la conductance sonique C telle que définie

dans la norme ISO 6358-1du distributeur de commande (légende 1) doit être supérieure à la valeur C

de l’orifice de pilotage du distributeur soumis à essai (légende 4). Il convient que le raccordement entre

le distributeur de commande (légende 1) et le tube de mesure de pression (légende 5) à l’orifice de

pilotage du distributeur soumis à essai soit aussi court que possible.
© ISO 2022 – Tous droits réservés
---------------------- Page: 8 ----------------------
ISO/FDIS 12238:2022(F)
Légende
1 distributeur de commande (pour générer le signal de commande)
2 capteurs de pression
3 dispositif(s) d’enregistrement de sortie
4 distributeur soumis à essai
5 tube de mesure de pression en conformité avec l’ISO 6358-1
6 robinet d’isolement (facultatif)
7 thermomètre
8 réservoir d’alimentation
9 limiteur de débit (uniquement pour les positions fermées)
10 capteur de débit (uniquement pour les positions fermées)
Figure 2 — Équipement d’essai pour distributeurs à commande pneumatique
5.2 Tubes de mesure de pression

5.2.1 Il convient qu’un tube de mesure de pression droit soit vissé dans l’orifice d’entrée du

distributeur et aussi dans l’orifice de pilotage du distributeur, le cas échéant, et qu’il soit réalisé

conformément à l’ISO 6358-1.

L’installation d’essai de l’ISO 6358-1 nécessite des connecteurs de transition pour le mesurage du

débit. Ceux-ci réduisent la vitesse de l’écoulement dans le tube de mesure. Cette disposition n’est pas

nécessaire pour le mesurage du temps de commutation et les connecteurs de transition ne sont donc

pas requis pour cet essai. Les connecteurs de transition de l’ISO 6358-1 peuvent néanmoins être utilisés

pour les essais réalisés conformément à l’ISO 12238.
© ISO 2022 – Tous droits réservés
---------------------- Page: 9 ----------------------
ISO/FDIS 12238:2022(F)

5.2.2 Choisir et raccorder les tubes de mesure de pression dont les filetages correspondent à chaque

taille d’orifice du distributeur soumis à essai et à son orifice de pilotage, le cas échéant.

5.3 Capteurs de pression

5.3.1 Installer un capteur de pression dans le tube de mesure de la pression d’entrée. Installer

également un capteur de pression directement dans chaque orifice de sortie à soumettre à essai, de

manière à avoir un volume de sortie aussi réduit que possible. Tous les orifices de sortie non soumis à

essai doivent être bouchés.

5.3.2 Lorsqu’un distributeur à commande pneumatique est soumis à essai, monter un capteur de

pression de commande supplémentaire dans le tube de mesure de la pression de pilotage.

5.4 Réservoir d’alimentation

5.4.1 Utiliser un réservoir d’alimentation d’une capacité suffisante pour que la perte de charge causée

par la tuyauterie et mesurée dans le tube de mesure de pression au niveau de l’orifice d’entrée pendant

l’essai ne dépasse pas 3 % de la pression d’alimentation. Une perte de charge supérieure est admise,

mais augmentera le temps de commutation et entraînera un classement moins favorable du produit

soumis à essai. Il convient que les connexions à partir du réservoir d’alimentation soient plusieurs fois

plus grandes que le tube de mesure de pression et aussi courtes que possible, pour minimiser la perte

de charge.

5.4.2 Utiliser un réservoir d’alimentation qui permet la mesure de la température de l’air à l’intérieur

du réservoir. Maintenir la température du réservoir d’alimentation entre 18 °C et 30 °C.

5.4.3 Positionner le robinet d’isolement facultatif et le distributeur de commande, le cas échéant,

aussi près que possible de la sortie du réservoir. Utiliser un distributeur dont la valeur C est plus grande

que celle du tube de mesure de pression, car un distributeur plus petit peut réduire l’écoulement et

augmenter le temps de commutation.
5.5 Signal de commande

5.5.1 Pour des distributeurs commandés par un solénoïde piloté ou pour des distributeurs à

commande pneumatique, maintenir la pression d’alimentation externe de pilotage soit à la pression

d’essai fournie au distributeur, soit à la pression d’alimentation de pilotage maximale admise, en

choisissant la plus basse des deux.
5.5.2 Pour des distributeurs commandés par un sol
...