EN 61298-2:1995
(Main)Process measurement and control devices - General methods and procedures for evaluating performance - Part 2: Tests under reference conditions
Process measurement and control devices - General methods and procedures for evaluating performance - Part 2: Tests under reference conditions
Specifies general methods and procedures for conducting tests and reporting on the functional and performance characteristics of process measurement and control devices.
Prozeßmeß-, -steuer- und -regelgeräte - Allgemeine Methoden und Verfahren für die Bewertung des Betriebsverhaltens - Teil 2: Prüfungen unter Referenzbedingungen
Dispositifs de mesure et de commande de processus - Méthodes et procédures générales d'évaluation des performances - Partie 2: Essais dans les conditions de référence
Spécifie les méthodes et procédures générales pour l'exécutions des essais portant sur les caractéristiques fonctionnelles et les caractéristiques de performances des dispositifs de mesure et de commande de processus.
Process measurement and control devices - General methods and procedures for evaluating performance - Part 2: Tests under reference conditions (IEC 61298-2:1995)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-november-1998
Process measurement and control devices - General methods and procedures for
evaluating performance - Part 2: Tests under reference conditions (IEC 61298-
2:1995)
Process measurement and control devices - General methods and procedures for
evaluating performance -- Part 2: Tests under reference conditions
Prozeßmeß-, -steuer- und -regelgeräte - Allgemeine Methoden und Verfahren für die
Bewertung des Betriebsverhaltens -- Teil 2: Prüfungen unter Referenzbedingungen
Dispositifs de mesure et de commande de processus - Méthodes et procédures
générales d'évaluation des performances -- Partie 2: Essais dans les conditions de
référence
Ta slovenski standard je istoveten z: EN 61298-2:1995
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.
CEI
NORME
IEC
INTERNATIONALE
1298-2
INTERNATIONAL
Première édition
STANDARD
First edition
1995-07
Dispositifs de mesure et de commande
de processus —
Méthodes et procédures générales d'évaluation
des performances —
Partie 2:
Essais dans les conditions de référence
Process measurement and control devices —
General methods and procedures for evaluating
performance —
Part 2:
Tests under reference conditions
© CEI 1995 Droits de reproduction réservés — Copyright — all rights reserved
Aucune partie de cette publication ne peut âtre reproduite ni No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun pro- any form or by any means, electronic or mechanical,
cédé, électronique ou mécanique, y compris la photocopie et including photocopying and microfilm, without permission
les microfilms, sans l'accord écrit de l'éditeur. in writing from the publisher.
Bureau Central de la Commission Electrotechnique Internationale 3, rue de Varembé Genève, Suisse
Commission Electrotechnique Internationale CODE PRIX
International Electrotechnical Commission
PRICE CODE U
I Mew,ayHapoAHaa 3neHrpote%HH4ecKaa HOMHCCHA
EC
Pour prix, voir catalogue en vigueur
•
For price, see current catalogue
1298-2 ©IEC:1995 - 3 -
CONTENTS
Page
FOREWORD 5
INTRODUCTION 7
Clause
1 Scope 9
2 Normative references 9
3 Definitions 9
4 Accuracy related factors 13
13 4.1 Test procedures and precautions
4.2 Specific testing procedures and precautions for the determination
of dead band
5 Dynamic behaviour
5.1 General considerations
29 5.2 General testing procedures and precautions
5.3 Frequency response
5.4 Step response 31
Functional characteristic 31
6.1 General
31 6.2 Input resistance of an electrical device
6.3 Insulation of electrical devices 37
6.4 Power consumption 39
41 6.5 Output ripple of a device with an electrical d.c. output
6.6 Air flow characteristics of a pneumatic device
6.7 Limits of adjustments of lower range value and span
6.8 Switching differential
47 Drift
7.1 Start-up drift
7.2 Long-term drift
51 Annex A - Bibliography
1298-2 © I 5 –
EC:1995 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
PROCESS MEASUREMENT AND CONTROL DEVICES —
GENERAL METHODS AND PROCEDURES
FOR EVALUATING PERFORMANCE —
Part 2: Tests under reference conditions
FOREWORD
The IEC (International Electrotechnical Commission) is a worldwide organization for standardization
1)
comprising all national electrotechnical committees (IEC National Committees). The object of the IEC is to
promote international cooperation on all questions concerning standardization in the electrical and
electronic fields. To this end and in addition to other activities, the IEC publishes International Standards.
Their preparation is entrusted to technical committees; any IEC National Committee interested in
the subject dealt with may participate in this preparatory work. International, governmental and
non-governmental organizations liaising with the IEC also participate in this preparation. The IEC
collaborates closely with the International Organization for Standardization (ISO) in accordance with
conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of the IEC on technical matters, prepared by technical committees on
which all the National Committees having a special interest therein are represented, express, as nearly as
possible, an international consensus of opinion on the subjects dealt with.
They have the form of recommendations for international use published in the form of standards, technical
3)
reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
International Standard IEC 1298-2 has been prepared by sub-committee 65B: Devices, of
IEC technical committee 65: Industrial-process measurement and control.
The text of this standard is based on the following documents:
DIS Report on voting
65B/248/RVD
65B/229/DIS
Full information on the voting for the approval of this standard can be found in the report
on voting indicated in the above table.
Process measurement and
IEC 1298 consists of the following parts, under the general title
control devices – General methods and procedures for evaluating performance:
– rt 1: General considerations
Pa
– Part 2: Tests under reference conditions
– Part 3: Tests for the effects of influence quantities
- Part 4: Evaluation report content
Annex A is for information only.
7 —
1298-2 © I EC:1995 —
INTRODUCTION
This standard is not intended as a substitute for existing standards, but is rather intended
as a reference document for any future standards developed within the IEC or other
standards organizations, concerning the evaluation of process instrumentation. Any
revision of existing standards should take this standard into account.
This common standardized basis should be utilised for the preparation of future relevant
standards, as follows:
Any test method or procedure, already treated in this standard, should be specified
—
and described in the new standard by referring to the corresponding clause of this
standard.
Any particular method or procedure, not covered by this standard, should be
—
developed and specified in the new standard in accordance with the criteria, as far as
they are applicable, stated in this standard.
Any conceptual or significant deviation from the content of this standard, should be
—
clearly identified and justified if introduced in a new standard.
1298-2 ©IEC:1995 - 9 -
PROCESS MEASUREMENT AND CONTROL DEVICES —
GENERAL METHODS AND PROCEDURES
FOR EVALUATING PERFORMANCE —
Part 2: Tests under reference conditions
1 Scope
This International Standard specifies general methods and procedures for conducting tests
and reporting on the functional and performance characteristics of process measurement
and control devices. The methods and procedures specified in this standard are applicable
to any kind of test or to any type of process measurement and control device. The tests
are applicable to any such devices characterized by their own specific input and output
variables, and by the specific relationship (transfer function) between the inputs and
outputs, and include analogue and digital devices. For devices that require special tests,
this standard shall be used, together with any product specific standard specifying special
tests.
This part covers tests made under reference conditions.
2 Normative references
The following normative documents contain provisions which, through reference in this
text, constitute provisions of this part of IEC 1298. At the time of the publication, the
editions indicated were valid. All normative documents are subject to revision, and parties
to agreements based on this part of IEC 1298 are encouraged to investigate the possibility
of applying the most recent editions of the normative documents indicated below.
Members of IEC and ISO maintain registers of currently valid International Standard.
Controllers with analogue signals for use in industrial-process control
IEC 546-1: 1987,
rformance
systems - Part 1: Methods of evaluating the pe
Industrial-process measurement and control - Terms and definitions
IEC 902: 1987,
Safety requirements for electrical equipment for measurement, control,
IEC 1010-1: 1990,
and laboratory use - Part 1: General requirements
Amendment No. 1 (1992)
Process measurement and control devices - General methods and pro-
IEC 1298-1:
cedures for evaluating performance - Part 1: General considerations
3 Definitions
For the purpose of this part of IEC 1298 the following definitions apply. Those marked with
an asterisk (*) are identical with those given in IEC 902, but that document has additional
notes.
1298-2 © I - 11 -
EC:1995
3.1 DUT: The device under test.
3.2 variable*: A quantity or condition whose value is subject to change and can usually
be measured (e.g., temperature, flow rate, speed, signal, etc.).
3.3 signal*: Physical variable, one or more parameters of which carry information about
one or more variables which the signal represents.
3.4 range*: Region of the values between the lower and upper limits of the quantity
under consideration.
3.5 span*: Algebraic difference between the upper and lower limit values of a given
range.
3.6 set point*: A signal representing the reference variable.
NOTE – It may be manually set, automatically set, or programmed.
3.7 inaccuracy*: Maximum positive and negative deviation from the specified charac-
teristic curve observed in testing a device under specified conditions and by a specified
procedure.
3.8 error*: Algebraic difference between the measured value and the true value of the
measured variable.
NOTE – The error is positive when the measured value is greater than the true value. The error is gener-
ally expressed as a percentage of the relevant ideal span.
3.9 maximum measured error: Largest positive or negative value of error of the
average upscale or downscale value at each point of measurement.
3.10 non-conformity: Deviation from conformity.
NOTE – Conformity is defined in IEC 902.
3.11 non-linearity: Deviation from linearity.
NOTES
1 Linearity is defined in IEC 902.
2 Non-conformity and non-linearity do not include hysteresis.
3.12 non-repeatability: See definition of repeatability error in IEC 902.
3.13
hysteresis: Property of a device or instrument whereby it gives different output
values in relation to its input values depending on the directional sequence in which the
input values have been applied.
3.14 dead band*: Finite range of values within which variation of the input variable does
not produce any noticeable change in the output variable.
3.15 Smallest possible change in output produced by a change to the
adjustability:
adjusting mechanism.
1298-2 © I EC:1995 - 13 -
Time interval between the instant when the variation of an input
3.16 dead time*:
variable is produced, and the instant when the consequent variation of the output variable
starts (see IEC 902, figure 1-2).
3.17 time*: For a step response, the time interval between the instant when the
rise
output signal, starting from zero, reaches a small specified percentage (for instance 10 %)
of the final steady-state value, and the instant when it reaches for the first time a specified
large percentage (for instance 90 %) of the same steady state value (see IEC 902,
figure 1-2).
Time interval between the step change of an input signal, and the
3.18 settling time:
instant when the resulting variation of the output signal does not deviate more than a
specified tolerance from its final steady state value. For this standard, a tolerance of 1 %
is adopted.
time: Time from a step change in the input signal to a system for
3.19 step response
the change in output of the system to reach for the first time 90 % of its final steady state
value (see IEC 902, figure 1-2).
3.20 time constant*: Time required to complete 63,2 % of the total rise or decay of the
output of a first-order linear system, initiated by a step or an impulse to the input.
3.21 transient overshoot*: For a step response, the maximum transient deviation from
the final steady state value of the output variable, expressed in % of the difference
between the final and the original steady state values.
event: Device breakdown, failure to work, anomaly, or inadvertent
3.22 unexpected
damage occurring during an evaluation which requires correction by the device manu-
facturer.
procedure: Statement of the tests to be carried out, and the conditions for
3.23 test
each test, agreed between the manufacturer, the test laboratory, and the purchaser/user
before the evaluation starts.
4 Accuracy related factors
4.1 Test procedures and precautions
4.1.1 Selection of ranges for test
Where there are switched ranges or dial settings (e.g., gain), the tests shall be repeated to
cover all ranges or settings. Where the DUT is supplied calibrated for use, the first set of
tests shall be carried out without adjustment.
4.1.1.1 Criteria
The measurements shall be performed with the devices operating at the minimum number
rf
of calibration settings necessary to establish the device pe ormance in all required
operational settings required by the test programme (see clause 5 of IEC 1298-1).
1298-2 ©IEC:1995 - 15 -
Testing of a device which has provision for substantial adjustment of both span and lower
range value may require an impractically large number of tests. In such a case, pre-
liminary tests shall be conducted to determine the effect of changing span and lower range
value adjustments on the characteristic being measured. This should enable some tests to
be eliminated from the test programme in cases where the characteristic can be inferred
reliably from fewer tests. For example, hysteresis may not be significantly affected by
selection of the lower and upper range value if the span is held constant, and often may
be inferred for different spans from measurements at a single span setting.
However, the report shall indicate clearly relevant values of the measured parameters for
each setting of the adjustments, so that the values of i
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.