EN 61298-2:1995

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

• Status: Withdrawn
• Publication Date: 04-Oct-1995
• Withdrawal Date: 30-Jun-1996
• ICS: 35.240.50 - IT applications in industry
• Technical Committee: CLC/SR 65B - Devices & process analysis
• Drafting Committee: IEC/SC 65B - IEC_SC_65B
• Parallel Committee: IEC/SC 65B - IEC_SC_65B
• Current Stage: 9960 - Withdrawal effective - Withdrawal
• Start Date: 01-Nov-2011
• Completion Date: 01-Nov-2011
• Ref Project: SIST EN 61298-2:1998 - Process measurement and control devices - General methods and procedures for evaluating performance -- Part 2: Tests under reference conditions

Relations

• Replaced By: EN 61298-2:2008 - Process measurement and control devices - General methods and procedures for evaluating performance - Part 2: Tests under reference conditions
• Effective Date: 29-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 61298-2:1998
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
SIST EN 61298-2:1998 en

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

---------------------- Page: 1 ----------------------
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
Pour prix, voir catalogue en vigueur
For price, see current catalogue
---------------------- Page: 2 ----------------------
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
25
of dead band
27
5 Dynamic behaviour
27
5.1 General considerations
29 5.2 General testing procedures and precautions
29
5.3 Frequency response
5.4 Step response 31
Functional characteristic 31
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
41
6.6 Air flow characteristics of a pneumatic device
45
6.7 Limits of adjustments of lower range value and span
47
6.8 Switching differential
47 Drift
47
7.1 Start-up drift
49
7.2 Long-term drift
51 Annex A - Bibliography
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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

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

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
– 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.
---------------------- Page: 4 ----------------------
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.
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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.
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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.
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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

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).

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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 inaccuracy, hysteresis, etc, can all

be referenced to the same adjustment of the device.
4.1.1.2 Setting of span and lower range value adjustments

Generally, unless otherwise specified in the test programme, the test for accuracy related

factors shall be carried out with the adjustments set at the settings A, B, C, D, listed

below, and in accordance with table 1 whenever the span and/or the lower range value

adjustments are adjustable further than the adjustments for the manufacturing tolerances.

NOTE - For tests of dynamic behaviour, functional characteristics, and drift, refer to the appropriate

clauses of this standard.
Table 1 - Settings of span and lower range value adjustments
Zero suppression
Adjustable span
Kind of test
and/or elevation
Performance evaluation A B
Type test
Routine tests
C D
Sample test

Setting A - Span adjustment set at the maximum and minimum values specified by the

manufacturer, and at one intermediate value.

Setting B - Normally, tests will be done at only one setting of lower range value, without

suppression or elevation, but further tests at minimum and maximum settings
may be required if the effects are significant.

Setting C - Unless otherwise specified in the test programme, the span shall be as set by

the manufacturer.

Setting D - Unless otherwise specified in the test programme, the lower range value shall

be as set by the manufacturer.
---------------------- Page: 9 ----------------------
– 17 –
1298-2 © IEC:1995
4.1.2 Preconditioning cycles
shall be preconditioned (see 7.12 of IEC 1298-1)
Prior to recording observations, the DUT
and shall be exercised by three full range traverses in each direction.
4.1.3 Number of measurement cycles and test points
shall be verified over the full range for increasing and
The performance of the DUT
decreasing values.

Taking into account the economic aspects outlined in 5.2 of IEC 1298-1, the number of

measurement cycles and of test points shall be the lowest possible. The number and

location of the test points shall be consistent with the kind of test, the degree of accuracy

desired, and the characteristic being evaluated.

The number of increasing and decreasing test points shall be the same for each pre-

determined test point, with the exception of 0 % and 100 %, that are reached only when

going downscale or upscale.

The number of measurement cycles and the number of the test points depend on the kind

of test under consideration. Unless otherwise specified for a particular type of device, the

values and locations that should be adopted are given in table 2.
Additional tests where digital inputs and outputs are provided
4.1.4

Tests shall be made to ensure that the protocols comply with international standards

(e.g., RS 232, IEEE 488) or the protocols fully specified by the DUT supplier. Tests shall

be carried out to confirm that the DUT functions correctly to the specified protocol under

reference conditions, and without error (or within any error rate specified by the supplier).

The levels of logical "1" and "0" shall be determined. Appropriate tests shall also be made

for display errors (missing digit sections, etc.), brightness, contrast, and angle of view

before loss of brightness/contrast. The update rate shall be recorded, together with display

(accuracy) errors.
4.1.5 Measurement procedure

The first measurement shall be performed to the first significant value of the scale after

0 % of input span (e.g., 10 % of input span – see table 2).

Initially, an input signal equal to the lower range value is generated, and then the input

signal is slowly increased to reach, without overshoot, the first test point; after an

adequate stabilization period, the value of the corresponding input and output signal is

noted.

Then the input signal is slowly increased to reach, without overshoot, the value of the next

test point and, after a stabilization period, the corresponding value of the output signal is

recorded.

The operation is repeated for all the predetermined values up to 100 % of the input span.

After measurement at this point, the input signal is slowly brought down to the test value

directly below 100 % of input span, and then to all the other values in turn down to 0 % of

input span, thus closing the measurement cycle.
---------------------- Page: 10 ----------------------
1298-2 © 19 -
IEC:1995 -
Table 2 - Number of measurement cycles and number and location of test points
Number of Number Location of
Kind of test measurement of test test points
cycles points (% of input span)
Performance evaluation 0-20-40-60-80-100
3 or 5
Type tests 11 0-10-20-30-40-50-60-70-80-90-100
Routine tests 1 5 0-25-50-75-100
Sample tests
4.1.6
Processing of the measured values

The difference between the output signal values obtained at the various test points for

each upscale and downscale traverse and the corresponding ideal values are recorded as

the output errors.

The errors generally shall be expressed as percent of the ideal output scan. On certain

devices (e.g., recorders, or devices with adjustable gain), it may be more convenient to

express the errors as percent of nominal input scan (see 7.16 of I EC 1298-1).

For each measuring point, the readings obtained in successive cycles for upscale and

downscale error, respectively, shall be averaged to give average upscale and downscale

values, and these averaged to give the average value at that point.

All the error values thus obtained shall be shown in a table (see table 3), and the average

values shall be presented graphically (see figure 1).
4.1.7 Determination of accuracy related factors

Because of the limited number of measurements (see 4.1.3), the accuracy related factors

shall be determined by treating the errors in a mathematically simple way, and not on the

basis of statistical methods. The different methods of treatment are described in the

following clauses.

4.1.7.1 Inaccuracy: Inaccuracy is determined from table 3 by selecting the greatest

positive and negative deviations of any measured value from the ideal value for increasing

and decreasing inputs for any test cycle separately, and reporting this in percent of ideal

output span.

4.1.7.2 measured error: Measured error is determined from table 3 by selecting the

greatest positive or negative value from the average upscale errors and the average down-

scale errors.

4.1.7.3 non-linearity: For devices that have a linear input/output relationship, the

non-linearity is determined from the curve plotted using the overall average of corre-

sponding upscale and downscale average errors (see table 3 and figure 1).
---------------------- Page: 11 ----------------------
- 21 -
1298-2 ©IEC:1995

The maximum positive or negative deviation between the average curve and the selected

straight line, expressed in percent of ideal output scan, is the non-linearity, and is

independent of dead band and hysteresis.
a) Terminal based non-linearity
Terminal based non-linearity is determined by drawing a straight line so that it

coincides with the average calibration curve at the upper range value and at the lower

range value.

NOTE - Where calibrations in workshops and adjustments in the field are made, only terminal based

non-linearity is of practical interest. Other expressions of non-linearity are sometimes used.

b) Independent non-linearity

Independent non-linearity is determined by drawing a straight line through the average

curve in such a way as to minimize the maximum deviation. It is not necessary that the

straight line be horizontal, or pass through the end points of the average calibration curve.

c) Zero based non-linearity

Zero based non-linearity is determined by drawing a straight line so that it coincides

with the average calibration curve at the lower range value (zero), and minimizes the

maximum deviation.
Table 3 - Typical table of device errors
Total
Average of
2nd cycle 3rd cycle
1st cycle
the cycles average
Error (in % of ideal span)
Average
Up Down Up Down
Up Down Up Down
Input
actual average error
actual actual actual actual
actual actual
in %
span
% % % %
% % %
-0,05 -0,050
-0,05 0,06
0 -0,04
+0,05 +0,16 0,05 0,15 0,100
10 +0,06 +0,14 +0,04 +0,15
0,175
00,26) +0,09 +0,26 0,10 0,25
20 (+0,13 +0,23 00,08)
• +0,26 0,10 0,25 0,175
+0,24 +0,09 +0,25 +0,10
30 +0,11 a
0,050
-0,04 +0,17 -0,05 0,15
40 -0,04 +0,13 00,07 +0,15
-0,15 0,00 -0,075
-0,16 +0,01 -0,13 +0,01
50 -0,18 -0,02
-0,10 -0,23 -0,08 -0,025 -0,10 -0,175
60 -0,27 -0,12 -0,25
0,30) -0,15 -0,225
-0,30 -0,16 -0,28 -0,12
70 C0,3-2) -0,17
• •
-0,15 -0,22 -0,13 -0,25 -0,15 -0,200
80 -0,27 -0,17 -0,26
-0,04 -0,15 -0,05 -0,100
-0,15 -0,05 -0,14
90 -0,16 -0,06
0,100
+0,10 0,10
100 +0,09 +0,11
Non-repeatability = 0,05 %
Maximum measured error = -0,30 %
Hysteresis = 0,22 %
band
= hysteresis error + dead
uracy = -0,32 /° +0, 26
---------------------- Page: 12 ----------------------
— 23 —
1298-2 © I EC:1995
Deviation, percent of ideal
output span
0,3
0 independent non-linearity = ± 0,18 %
average
Downscale
terminal based non-linearity = ± 0,28 %
Average
0,2 zero based non-linearity = ± 2,1 %
^ e `‘
0,1
based straight
,Terminal
line WM
,Alm.
based straight line
Zero
Will
V1r4P
rnl•–-sillIllIllanlnillr,■=
imow
■illn 1111._11.=
riffl
Independen
0,1 la line r r
Upscale average
MIN MN
0,2
-•-•-•-•
11.
IM NM
0,3
100
50 60 70 80 90
0 10 20 30 40
Percent input span
/EC 664/95
Figure 1 – Error curves
term non-conformity (terminal based non-conformity, inde-
4.1.7.4 non -conformity: The

pendent non-conformity, and zero based non-conformity) should be used for devices

which have a non-linear input-output relationship (e.g., logarithmic, square root, etc.).

The non-conformity is determined and presented using the same procedures as for
non-linearity.
Hysteresis is determined directly from the deviation values shown in
4.1.7.5 hysteresis:

table 3, and it is the difference between consecutive upscale and downscale outputs for

any single test cycle at the same test point.

The maximum value observed from all the test cycles is reported, and shall be expressed

as percent of the ideal output scan. If required, hysteresis error may be determined by

subtracting the value of dead band from the corresponding value of hysteresis for a given

measured point; its maximum value may be reported in percent of the ideal output scan.

NOTE — Dead band may be determined by a conventional dead band test as described in 4.2.2.

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1298-2 © IEC:1995 - 25 -

4.1.7.6 non-repeatability: The non-repeatability is the algebraic difference between the

extreme values obtained by a number of consecutive measurements of the output over a

period of time, for the same value of the input, under the same operating conditions,

sho rt
approaching from the same direction, for full range traverses.

Non-repeatability is usually expressed in percentage of ideal output span, and does not

include hysteresis.

Non-repeatability is determined directly from table 3. Observe the maximum difference in

percent of the ideal output span, between all values of output for any single input value,

considering upscale and downscale curves separately. The maximum value from either

upscale or downscale value is reported as non-repeatability.
4.1.8
Presentation of the results

The results of measurements made during the tests shall be presented in the repo rt

by

including figures corresponding to table 3 and figure 1. These figures shall be included in

the test repo rt .
The values of inaccuracy, or measured error, or non-conformity, hysteresis, and

non-repeatability shall be determined in accordance with 4.1.7, and tabulated in the test

repo rt .

The corresponding values of the accuracy related factors specified by the manufacturer

shall be tabulated alongside the values determined from the tests.

Note that the accuracy related terms may be stated by the manufacturer either as:

- the inaccuracy (which includes hysteresis and non-repeatability) and the hysteresis; or

the measured error (which includes hysteresis) and the hysteresis; or

- the non-linearity/non-conformity (which does not include hysteresis), the hysteresis

and the dead band.

4.2 Specific testing procedures and precautions for the determination of dead band

4.2.1 Selection of ranges for test and preconditioning

Dead band is measured by using the same ranges and preconditioning as for the deter-

mination of accuracy related factors in 4.1.1 (table 1) and 4.1.2.
4.2.2 Measurement procedure

Unless the dead band is known to be insignificant, it shall be measured as follows. Dead

band shall be measured three times at each of three test points at 10 %, 50 % and 90 % of

span, by proceeding as follows:

a) slowly increase the input variable to the DUT until a detectable output change is

observed;
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1298-2 © I EC:1995 – 27 –
b) note the input value;
slowly decrease the input until a detectable output change is observed;
d) note the input value.

It shall be necessary to observe and record the output values at least three times, and

preferably five times, over full range traverses in each direction. The increment through

which the input signal is varied (difference between b) and d) above) is the dead band at

this point.
Presentation of the results
4.2.3

The maximum value of dead band at each test point, shall be tabulated, in percent of ideal

input span, in the test report.
DUT.
The maximum overall value shall be reported as the dead band of the

If the dead band value is specified by the manufacturer, this value shall be reported

beside the value determined in the test.
5 Dynamic behaviour
General considerations
5.1

The objective of this part of the standard is to give data that will characterize dynamic

ormance of the DUTs in a uniform, comparable manner.
pe rf

For the purposes of this standard, sine wave and step input signals may be used for

dynamic response tests, as required.

Sine wave test data are most generally useful for mathematical analysis, for graphical

rformance of linear
solution of control problems, and for characterization of dynamic pe
systems.

Step tests permit the measurement of the dead time, and give a qualitative evaluation of

the non-linearity of the DUT.

In order to arrive at a practical number of tests, in accordance with 5.2 of IEC 1298-1, for

the majority of equipment, only one value of output load and a minimum number of input

signal configurations need be adopted.

It is realized that the data from the specified step and sine wave tests will not suffice to

However, this standard is intended to give
describe completely non-linearities of the DUT.

comparable data useful to identify the dynamic behaviour of simple devices, and to give

qualitative indications for the more complex ones. In special cases, more detailed testing

may be specified in the test programme.
NOTE — The specified output loads and the
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