Iec 61298 2 2008

3.12 dead band finite range of values within which a variation of the input variable does not produce any measurable change in the output variable [IEV 351-24-14, modified] 3.13 dead-t

Test procedures and precautions

Selection of ranges for test

All ranges or dial settings, such as gain, must be tested to ensure comprehensive coverage Initial tests on the Device Under Test (DUT) should be conducted without any adjustments when it is supplied calibrated for use.

Measurements must be conducted using devices set to the minimum number of calibration settings needed to verify performance across all operational conditions specified in the test program, as outlined in Clause 5 of IEC 61298-1.

Testing a device with significant adjustments for both span and lower range value can lead to an impractically high number of tests To address this, preliminary tests should be performed to assess how changes in span and lower range value impact the measured characteristic This approach allows for the elimination of certain tests when reliable inferences can be made from fewer measurements For instance, if the span remains constant, hysteresis may not be significantly influenced by the selection of lower and upper range values, and it can often be inferred from measurements taken at a single span setting.

The report must clearly present the relevant values of the measured parameters for each adjustment setting, allowing for consistent reference to inaccuracy, hysteresis, and other factors related to the device's adjustments.

4.1.1.2 Setting of span and lower range value adjustments

Unless stated otherwise in the test program, accuracy-related tests should be conducted with adjustments set to A, B, C, and D, as outlined below, and in accordance with Table 1, whenever the span or lower range value adjustments exceed the manufacturing tolerances.

NOTE For tests of dynamic behaviour, functional characteristics, and drift, refer to the appropriate clauses of this standard

LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU.

Table 1 – Settings of span and lower range value adjustments

Kind of test Adjustable span Zero suppression and/or elevation

Setting A – Span adjustment set at the maximum and minimum values specified by the manufacturer, and at one intermediate value

In typical scenarios, tests are conducted at a single lower range value without any suppression or elevation However, if significant effects are observed, additional tests at both minimum and maximum settings may be necessary.

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.

Preconditioning cycles

Prior to recording observations, the DUT shall be preconditioned (see 7.12 of IEC 61298-1) and shall be exercised by three full range traverses in each direction.

Number of measurement cycles and test points

The performance of the DUT shall be verified over the full range for increasing and decreasing values

According to the economic considerations in section 5.2 of IEC 61298-1, it is essential to minimize the number of measurement cycles and test points The selection and placement of these test points should align with the type of test being conducted, the required accuracy level, and the specific characteristics being assessed.

The number of increasing and decreasing test points must be consistent for each predetermined test point, except for the 0% and 100% levels, which are only achieved during downscaling or upscaling processes.

The measurement cycles and test points vary based on the specific test being conducted Unless stated otherwise for a particular device type, the recommended values and locations are outlined in Table 2.

Additional tests where digital inputs and outputs are provided

Tests shall be made to ensure that the protocols comply with international standards (e.g., RS

Testing must be conducted to ensure that the Device Under Test (DUT) operates correctly according to the specified protocols, such as IEEE 488 or those defined by the supplier This includes verifying functionality under reference conditions and within any acceptable error rates Additionally, the logical levels of "1" and "0" must be established, and tests for display errors should also be performed.

(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.

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)

An input signal is first generated at the lower range value and is gradually increased to reach the first test point without overshooting After allowing for a sufficient stabilization period, the corresponding values of the input and output signals are recorded.

The input signal is gradually increased to the next test point without overshooting, and after a stabilization period, the output signal value is recorded.

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

The input signal is gradually reduced to the test value just below 100% of the input span, followed by sequential adjustments to all other values down to 0% of the input span, effectively completing the measurement cycle.

Table 2 – Number of measurement cycles and number and location of test points

Location of test points (% of input span)

Processing of the measured values

The output errors are calculated by recording the differences between the signal values obtained at various test points during both upscale and downscale traverses and their corresponding ideal values.

Errors are typically represented as a percentage of the ideal output span However, for specific devices such as recorders or those with adjustable gain, it can be more practical to express errors as a percentage of the nominal input span, as outlined in section 7.16 of IEC 61298-1.

At each measuring point, the readings from successive cycles for both upscale and downscale errors are averaged to determine the average upscale and downscale values, which are then combined to yield the overall average value at that specific 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).

Determination of accuracy related factors

Due to the limited number of measurements, accuracy-related factors will be assessed using a straightforward mathematical approach rather than statistical methods The various treatment methods are outlined in the subsequent sections.

Inaccuracy is assessed by identifying the maximum positive and negative deviations of measured values from the ideal value, based on Table 3 This evaluation is conducted for both increasing and decreasing inputs during each test cycle, with results expressed as a percentage of the ideal output span.

Maximum measured error is determined from table 3 by selecting the greatest positive or negative value from the average upscale errors and the average downscale errors

For devices exhibiting a linear input/output relationship, the non-linearity is assessed through a curve that represents the overall average of the corresponding upscale and downscale average errors, as illustrated in Table 3 and Figure 1.

Non-linearity refers to the maximum deviation, either positive or negative, between the average curve and a chosen straight line, expressed as a percentage of the ideal output span This concept is independent of factors such as dead band and hysteresis, specifically in the context of terminal-based non-linearity.

Terminal-based non-linearity is established by aligning a straight line with the average calibration curve at both the upper and lower range values.

In calibration workshops and field adjustments, only terminal-based non-linearity is practically significant While other forms of non-linearity may be referenced, independent non-linearity remains a key focus.

Independent non-linearity is established by fitting a straight line to the average curve to minimize the maximum deviation This line does not need to be horizontal or intersect the endpoints of the average calibration curve Additionally, zero-based non-linearity is considered in this context.

Zero-based non-linearity is established by aligning a straight line with the average calibration curve at the lower range value (zero) while minimizing the maximum deviation.

Table 3 – Typical table of device errors

1 st cycle 2 nd cycle 3 rd cycle Average of the cycles Total average Error (in % of ideal span)

= hysteresis error + dead band Maximum measured error = –0,30 %

Up actual Down actual Up actual Down actual Up actual Down actual Up actual Down average Average error

A verage error, per cent o f i de al output s pan

Independent straight line Upscale average

Terminal based non-linearity = – 0,28 % and at ± 0,28 %

Figure 1 – Error curves 4.1.7.4 Non-conformity

Non-conformity refers to devices exhibiting a non-linear input-output relationship, including types such as terminal based non-conformity, independent non-conformity, and zero based non-conformity Examples of these relationships include logarithmic and square root functions.

The non-conformity is determined and presented using the same procedures as for non- linearity

Hysteresis is defined as the difference between consecutive upscale and downscale outputs during a single test cycle at the same test point, as indicated by the deviation values in Table 3.

Hysteresis is defined as the maximum value observed from all test cycles, expressed as a percentage of the ideal output span To determine hysteresis error, one can subtract the dead band value from the corresponding hysteresis value at a specific measured point, with the maximum hysteresis error also reported as a percentage of the ideal output span.

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

Non-repeatability refers to the algebraic difference between the maximum and minimum values recorded from a series of consecutive measurements of output, taken over a brief period, while keeping the input constant and under identical operating conditions, with measurements approaching from the same direction across the full range.

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

Non-repeatability is assessed by examining Table 3, which highlights the maximum percentage difference in the ideal output span for each input value This analysis is conducted separately for both upscale and downscale curves, with the highest value from either curve being reported as the non-repeatability measure.

Presentation of the results

The test report will include the results of measurements, featuring figures that correspond to Table 3 and Figure 1.

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 report

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.

Specific testing procedures and precautions for the determination of dead band

Selection of ranges for test and preconditioning

Dead band is measured by using the same ranges and preconditioning as for the determination of accuracy related factors in 4.1.1 (Table 1) and 4.1.2.

Measurement procedure

To accurately assess the dead band, it must be measured at three specific test points: 10%, 50%, and 90% of the span This process involves three key steps: first, gradually increase the input variable to the Device Under Test (DUT) until a noticeable output change occurs; second, record the input value; and finally, slowly decrease the input until another detectable output change is observed, noting this input value as well.

To ensure accurate measurements, it is essential to observe and record the output values a minimum of three times, ideally five times, during full range traverses in both directions The increment by which the input signal is varied defines the dead band at this stage.

Presentation of the results

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

The maximum overall value shall be reported as the dead band of the DUT

If the dead band value is specified by the manufacturer, this value shall be reported beside the value determined in the test

General considerations

The objective of this part of the standard is to give data that will characterize dynamic performance of the DUTs in a uniform, comparable manner

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 solution of control problems, and for characterization of dynamic performance of linear systems

Step tests permit the measurement of the dead time, and give a qualitative evaluation of the non-linearity of the DUT

To determine a practical number of tests as per section 5.2 of IEC 61298-1, it is sufficient for most equipment to adopt a single output load value and a minimal set of input signal configurations.

The data obtained from the step and sine wave tests alone are insufficient to fully characterize the non-linearities of the Device Under Test (DUT) Nonetheless, this standard aims to provide comparable data that helps identify the dynamic behavior of simpler devices and offers qualitative insights for more complex ones In certain instances, the test program may require more detailed testing procedures.

The output loads and input signal levels provided are adequate to meet standard testing requirements, offering qualitative insights into the impact of unusually large and fluctuating signals.

General testing procedures and precautions

Testing will be conducted by adjusting the span to the average of the maximum and minimum values, while setting the lower range value to the midpoint of its allowable adjustment range.

Adjustable functions, such as filters and dampers, should be utilized to modify the dynamic behavior of the Device Under Test (DUT) Testing must be conducted with these adjustments first set to their minimum effects, followed by evaluations at their maximum effects if necessary.

To evaluate the dynamic behavior of devices with electrical outputs, a realistic load can be simulated by connecting a 0.1 μF capacitor across the resistive load, unless otherwise specified in the test program.

Frequency response

A sinusoidal signal shall be applied by a function generator to the input of the DUT

The peak-to-peak amplitude of a sinusoidal signal must remain within 20% of the span, ensuring it is adequate for accurate measurements while preventing distortion or saturation of the output.

The input signal frequency will be gradually increased, starting from a low initial value sufficient to assess the static gain This process continues until reaching a higher frequency where the output is reduced to less than 10% of its initial amplitude or where the phase lag reaches 300°.

At least one complete cycle of the input and output shall be recorded simultaneously at each frequency step

The results of these tests shall be presented graphically in the following form (see Figure 2):

– the gain and the phase lag shall be plotted against frequency on a logarithmic scale

The analysis of the graphs reveals several key values: a) the frequency corresponding to a relative gain of 0.7; b) the frequency at which the phase lag reaches 45°; c) the frequency associated with a phase lag of 90°; d) the maximum relative gain along with its corresponding frequency and phase angle.

Step response

A sequence of step changes will be introduced to the input of the Device Under Test (DUT), ensuring that the rise time of the step input is significantly shorter than the DUT's response time.

Input step and output response shall be recorded together

The following input steps shall be applied:

– a step corresponding to 80 % of output span, giving an output change from 10 % to 90 %, then another from 90 % to 10 %;

– steps, corresponding to 10 % output span, giving output changes up and down as follows:

The time for the output to reach and remain within 1 % of output span of its final steady value

(settling time) shall be measured for each test condition The amount of dead time and transient overshot, if any, shall be stated (see Figure 3)

NOTE Measurement of step response time, or time constant, may also be useful

General

Certain tests necessitate powering the Device Under Test (DUT) These assessments should be conducted with the gain span set to the average of the maximum and minimum span, while the lower range value must be positioned near the midpoint of its allowable adjustment range Specific settings will be outlined for each individual test.

Input resistance of an electrical device

This test, applicable to voltage or current input devices, is to determine the effective resistance presented to d.c input signals at the input terminals of the device

The test is performed at 100 % input level, using the test setup shown in Figure 4

Figure 2 – Two examples of frequency response

Res pons e % o f ou tput c hange

Input step to produce required output response

Figure 3 – Two examples of responses to a step input

Figure 4 – Test set-up for input resistance

The test involves placing a resistance in series with the device's input circuit Measurements are taken of both the input signal voltage and the voltage drop across the series resistance After determining the actual resistance value, the input resistance is calculated using the appropriate formula.

R in is the input resistance, in ohms;

R s is the series resistance, in ohms;

E in is the voltage input signal of the DUT, in volts;

E rs is the voltage drop across the series resistance, in volts.

Insulation of electrical devices

General considerations

These tests serve as basic electrical safety checks and are not meant to provide a formal assessment of equipment safety or serve as design specifications For a comprehensive evaluation of safety in equipment design, refer to IEC 61010-1 The tests assess the insulation level of circuits from the device enclosure and evaluate the inherent safety when exposed to high voltages between circuits and the enclosure.

The insulation of the device shall be adequate to give a sufficient dielectric strength to prevent breakdown, and a sufficient dielectric resistance to prevent excessive leakage currents, or thermal breakdown

Before conducting type tests on insulation, the device must be stored for 4 hours in a dry chamber at a temperature of 32 °C to 38 °C (or 42 °C to 48 °C for tropicalized devices) This is followed by an additional 24 hours at the same temperature with a relative humidity of 90% to 95%, which must be maintained during the subsequent tests All tests should be carried out under these high humidity conditions.

Insulation resistance

The Device Under Test (DUT) must be configured for standard operation Insulation resistance for each input and output circuit should be assessed if it is isolated from the earth This testing is conducted on the unpowered DUT by applying a direct current (d.c.) test voltage between the short-circuited input, output, or power supply terminals and the enclosure that is grounded.

To prevent voltage surges, it is essential to gradually increase the applied test voltage to its maximum value and then decrease it gradually after the test period Unless specified otherwise, the standard nominal direct current (d.c.) test voltage is set at 500 V.

After application of the full test voltage for at least 30 s, the value of insulation resistance shall be reported.

Dielectric strength

The r.m.s value of the test voltage must be based on the rated voltage or insulation voltage of the Device Under Test (DUT) and the manufacturer's specified safety class (I to II) When the DUT is unpowered and the case is fitted, the test voltage should be applied sequentially between the input, output, and power supply terminals and the earth Additionally, during each test, the case and terminals not directly involved must be connected and earthed.

The test voltage shall be a substantially sinusoidal alternating voltage with a frequency between 45 Hz and 65 Hz (mains frequency)

Table 4 – Dielectric strength test voltages

Rated voltage or isolation voltage d.c or a.c r.m.s

The test voltage must be gradually increased to the specified level without causing significant transients, and it should be held at this level for one minute.

During the test, no breakdown or flashover shall occur.

Power consumption

Electrical power consumption

This test shall be conducted at the input and load conditions which produce the maximum power consumption of the DUT

For alternating current (a.c.) power, the consumption in voltamperes must be measured using effective (r.m.s.) values Measurements should be conducted at the nominal voltage and frequency, as well as at the maximum voltage and minimum frequency specified by the manufacturer.

If the power is d.c., the watts consumed shall be measured at nominal supply voltage.

Air consumption

The test involves measuring the air consumption of the Device Under Test (DUT) under steady-state input conditions, with the output linked to a sealed container to prevent any airflow from the output.

The air consumption shall be measured, and recorded at the input level which produces the maximum consumption, at nominal supply pressure

The consumption shall be recorded in m 3 /h (at reference conditions; see 6.1 of IEC 61298-1)

Output ripple of a device with an electrical d.c output

The peak-to-peak values and the main frequency component of the output ripple content must be measured and documented using 10% and 90% input signals at both minimum and maximum load conditions.

Air flow characteristics of a pneumatic device

Initial setting up

The airflow characteristic is the relationship between the delivered/exhausted output airflow and the deviation of input (see Figure 6)

To accurately assess airflow characteristics, it is typically adequate to measure at a single span value, as variations in gain influence only the input scale, not the characteristic shape or maximum airflow values Additionally, it is advisable to measure airflow at one recommended supply pressure, while also considering the maximum and minimum specified supply pressures for comprehensive evaluation of delivered and exhausted airflow values.

Means to feed and measure air into or out of the output line should be installed, as shown in

To ensure accurate results, it is crucial to maintain an appropriate piping arrangement Specifically, avoid using long lengths and narrow bore pipes, and verify that the flow capacity of the supply pressure regulator exceeds the maximum flow delivered by the Device Under Test (DUT) as specified by the manufacturer.

Figure 5 – Test arrangement for measurement of airflow characteristics

To begin the test, ensure that both valves V1 and V2 are closed Make any necessary preliminary adjustments to the Device Under Test (DUT) and secure it in place Next, adjust the input signal until the output signal is balanced at 50% of its span, recording this input value as U0 If needed, the test can also be conducted at other output settings of 10% and 90%.

Delivered flow Q 1

Ensure that valve V 2 is closed

To achieve a small delivered flow rate, x, gradually open valve V1 Then, rebalance the output signal V to 50% of its span by readjusting the input signal U, and record this value as U1.

Determine the deviation of the input signal as: ΔU 1 = U 1 – U 0

To identify any discontinuities in the input signal deviation ΔU, gradually increase the flow rates until reaching the maximum flow rate, Q 1 max Afterward, ensure to close the valve V 1.

The maximum delivered flow Q 1 max is the maximum flow rate at which the output signal V can be rebalanced to its previous value of 50 %

NOTE Increasing flow rates over this value will cause a lower output value, which cannot be rebalanced by further re-adjustment of input signal U.

Exhausted flow Q 2

Ensure that valve V 1 is closed

Gradually open valve V 2 in order to feed a small exhausted flow rate of y into the DUT

Follow the procedure in 6.6.2 to determine the deviation of the input signal U up to the maximum flow Q 2 max

The maximum exhausted flow Q 2 max is the maximum flow rate at which the output signal V can be rebalanced to its previous value of 50 %

NOTE Increasing flow rates over this value will cause a higher output value, which cannot be rebalanced by further re-adjustment of input signal U.

Data presentation

The data should be plotted as shown in Figure 6

Figure 6 – Typical air flow characteristics

The analysis of the graph reveals several key results: a) the maximum delivered flow, denoted as \$Q_{1 \text{ max}}\$; b) the deviation \$\Delta U_{1}\$ observed at lower flow rates; c) the maximum exhausted flow, represented as \$Q_{2 \text{ max}}\$; d) the deviation \$\Delta U_{2}\$ at lower exhaust flow rates; e) the height of the output relay dead space expressed as a percentage of the input \$U\$ span, along with the associated air flow rate, whether delivered or exhausted Notably, the output relay dead space indicates a discontinuity in the flow characteristics illustrated in Figure 6.

The flow rate values should be reported for standard conditions (temperature and pressure) in m³/h Report also the adjusted gain and supply pressure value.

Limits of adjustments of lower range value and span

Adjustments for lower range values and spans can be categorized into two types: those that compensate for manufacturing tolerances and minor deviations, and those that modify the input signal range to align with the specified output range.

Manufacturers often make adjustments to account for manufacturing tolerances, sealing the adjusting means through encapsulation once the operation is complete If the adjusting means remain accessible, testing is required to establish the limits of adjustment This testing should encompass the four combinations of extreme settings for both the lower range value and span adjustment limits.

When testing a Device Under Test (DUT) with separate elevation or suppression adjustments, it is essential to evaluate this feature alongside the lower range value adjustment The elevation or suppression adjustment should be set to its extreme values, which will enhance the effect of each lower range value adjustment This approach effectively determines the absolute lower range value adjustment capability of the DUT.

Switching differential

This test aims to identify the differential gap in input values required to activate and deactivate a switching action, as defined by IEC 60050-351.

The test is performed at least three set switching points: 10 %, 50 %, and 90 % of input span

The input signal is changed gradually until the switch turns on The signal is reversed, and changed gradually until the switch is de-activated

The algebraic difference between the two input levels is the switching differential gap and should be expressed in percent of ideal input span

If the switch is equipped with adjustable dead band, the test is performed at minimum and maximum differential adjustment

Start-up drift

This test should be carried out by measurement of the changes which occur in the output after energizing the DUT

Before testing, the device must be acclimated to ambient environmental conditions, or as recommended by the manufacturer, for a minimum of 12 hours without being powered on The span should be calibrated to the average of the maximum and minimum values, with the lower range set around the midpoint of its allowable adjustment range.

To ensure proper functionality, apply a 90% input signal to the device and monitor the output until it stabilizes, which may take up to 4 hours Record the measurements obtained during this period and report the start-up drift as the time taken for the output to consistently fall within the manufacturer's specified limits.

Long-term drift

The device shall be operated for 30 days and, where practical, a steady input signal

For internal use at MECON Limited in Ranchi/Bangalore, it is essential to maintain the span at 90% and adjust it to the mean of the maximum and minimum values, with the lower range set at the midpoint of its permissible adjustment range In cases where devices have intermittent inputs or cannot maintain a constant test signal, a 90% span input must be applied daily Measurements of input and output should ideally occur each working day to assess and correct any output drift due to input variations It is crucial to account for environmental changes that may obscure long-term drift effects Additionally, the lower range value and span should be recorded before and after a 30-day test period, with the data analyzed to determine a best fit straight line to identify any directional or random drift.

4.1.3 Nombre de cycles de mesure et de points d'essai 37

4.1.4 Essais supplémentaires en cas d'entrées et sorties numériques 38

4.1.7 Détermination des facteurs liés à la précision 39

4.2 Procédure d'essai spécifique et précautions à prendre pour déterminer la zone d'insensibilité 42

4.2.1 Choix des étendues pour l'essai et le préconditionnement 42

5.2 Procédure générale d'essai et précautions 44

6.2 Résistance d'entrée des dispositifs électriques 45

6.5 Ondulation de sortie d'un dispositif à sortie électrique en courant continu 50

6.6 Caractéristiques de débit d'air d'un dispositif pneumatique 50

6.7 Limites de réglage de la valeur inférieure de l'étendue et de l'intervalle 52

Figure 2 – Deux exemples de réponse harmonique 46

Figure 3 – Deux exemples de réponse à une entrée variable par échelon 47

Figure 4 – Montage d'essai pour la mesure de la résistance d'entrée 48

Figure 5 – Montage d'essai pour la mesure de la caractéristique de débit d'air 50

Figure 6 – Caractéristique typique de débit d'air 51

Tableau 1 – Réglage de l'intervalle et de la valeur inférieure de l'étendue 37

Tableau 2 – Nombre de cycles de mesure; nombre et emplacement des points d'essai 38

Tableau 3 – Tableau d'erreurs typiques d'un dispositif 40

Tableau 4 – Tensions d'essai pour l'essai de rigidité diélectrique 49

DISPOSITIFS DE MESURE ET DE COMMANDE DE PROCESSUS –

MÉTHODES ET PROCÉDURES GÉNÉRALES D'ÉVALUATION DES PERFORMANCES – Partie 2: Essais dans les conditions de référence

The International Electrotechnical Commission (IEC) is a global standards organization comprising national electrotechnical committees Its primary goal is to promote international cooperation on standardization in the fields of electricity and electronics To achieve this, the IEC publishes international standards, technical specifications, technical reports, publicly accessible specifications (PAS), and guides, collectively referred to as "IEC Publications." The development of these publications is entrusted to study committees, which allow participation from any interested national committee Additionally, international, governmental, and non-governmental organizations collaborate with the IEC in its work The IEC also works closely with the International Organization for Standardization (ISO) under conditions established by an agreement between the two organizations.

Official decisions or agreements of the IEC on technical matters aim to establish an international consensus on the topics under consideration, as each study committee includes representatives from the relevant national IEC committees.

The IEC publications are issued as international recommendations and are approved by the national committees of the IEC While the IEC makes every reasonable effort to ensure the technical accuracy of its publications, it cannot be held responsible for any misuse or misinterpretation by end users.

To promote international consistency, the national committees of the IEC commit to transparently applying IEC publications in their national and regional documents as much as possible Any discrepancies between IEC publications and corresponding national or regional publications must be clearly stated in the latter.

5) La CEI n’a prévu aucune procédure de marquage valant indication d’approbation et n'engage pas sa responsabilité pour les équipements déclarés conformes à une de ses Publications

6) Tous les utilisateurs doivent s'assurer qu'ils sont en possession de la dernière édition de cette publication

The IEC and its administrators, employees, agents, including specialized experts and members of its study committees and national committees, shall not be held liable for any injury or damage, whether direct or indirect, arising from the publication or use of this IEC Publication or any other IEC Publication, nor for any associated costs, including legal fees and expenses.

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Attention is drawn to the fact that some elements of this IEC publication may be subject to intellectual property rights or similar rights The IEC cannot be held responsible for failing to identify such property rights or for not indicating their existence.

La Norme internationale CEI 61298-2 a été établie par le sous-comité 65B: Dispositifs et analyse des processus, du comité d'études 65 de la CEI: Mesure, commande et automation dans les processus industriels

Cette deuxième édition annule et remplace la première édition publiée en 1995 et constitue une révision technique

La présente édition est une révision globale par rapport à l’édition précédente et ne comporte pas de changements majeurs (voir Introduction)

Le texte de cette norme est issu des documents suivants:

Le rapport de vote indiqué dans le tableau ci-dessus donne toute information sur le vote ayant abouti à l'approbation de cette norme

Cette publication a été rédigée selon les Directives ISO/CEI, Partie 2

Une liste de toutes les parties de la série CEI 61298, présentées sous le titre général

Dispositifs de mesure et de commande de processus – Méthodes et procédures générales d'évaluation des performances, peut être consultée sur le site web de la CEI

The committee has decided that the content of this publication will not be modified until the maintenance date specified on the IEC website at "http://webstore.iec.ch" in the data related to the publication in question At that date, the publication will be updated.

• remplacée par une édition révisée, ou

This standard is not intended to replace existing standards but serves as a reference document for the development of future standards by both the IEC and other standardization bodies in the field of process instrumentation evaluation It is important to consider this standard when revising existing standards.

Lors de l'établissement de futures normes, il y aura lieu de respecter les éléments normatifs suivants:

Any testing method or procedure already included in this standard will be specified and described in the new standard by referencing the appropriate article of the current standard Therefore, the revised editions of this standard will not change the numbering of articles or their scope of application.

Any specific testing method or procedure not addressed by this standard should be developed and detailed in the new standard, in accordance with the criteria outlined in this standard, as far as they are applicable.

– tout écart fondamental ou important par rapport au contenu de la présente norme sera distinctement identifié et justifié, s'il est introduit dans la nouvelle norme

DISPOSITIFS DE MESURE ET DE COMMANDE DE PROCESSUS –

MÉTHODES ET PROCÉDURES GÉNÉRALES D'ÉVALUATION DES PERFORMANCES – Partie 2: Essais dans les conditions de référence

This section of IEC 61298 outlines the general methods and procedures for testing the functional and performance characteristics of measurement and process control devices These tests apply to any device characterized by its specific input and output parameters and the transfer function relating them The standard encompasses both analog and digital devices For devices requiring special testing, this standard should be used in conjunction with the specific product standard that details those special tests.

Cette norme couvre les essais effectués dans les conditions de référence

The following reference documents are essential for the application of this document For dated references, only the cited edition is applicable For undated references, the latest edition of the reference document, including any amendments, is applicable.

CEI 60050-300, Vocabulaire Electrotechnique International (VEI) – Mesures et appareils de mesure électriques et électroniques (constitué des Parties 311, 312, 313 et 314)

CEI 60050-351, Vocabulaire Electrotechnique International (VEI) – Partie 351:Technologie de commande et de régulation

CEI 61298-1, Dispositifs de mesure et de commande de processus – Méthodes et procédures générales d'évaluation des performances – Partie 1: Généralités

CEI 61010-1, Règles de sécurité pour appareils électriques de mesurage, de régulation et de laboratoire – Partie 1: Prescriptions générales

Pour les besoins du présent document, les termes et définitions suivants dont quelques-uns sont extraits de la CEI 60050(300) ou de la CEI 60050(351) s'appliquent

3.1 grandeur (variable) grandeur ou condition dont la valeur peut se modifier et qui peut en général être mesurée (par exemple température, débit, vitesse, signal, etc.)

3.2 signal grandeur physique dont un ou plusieurs paramètres sont porteurs d'informations sur une ou plusieurs autres grandeurs que le signal représente

3.3 étendue gamme des valeurs définie par deux valeurs extrêmes, entre lesquelles une variable peut être mesurée avec la précision spécifiée

3.4 intervalle différence algébrique entre les valeurs de la limite supérieure et de la limite inférieure de l’étendue de mesure

3.5 imprécision écart positif ou négatif maximal à partir de la courbe caractéristique spécifiée, observé quand un dispositif est essayé dans les conditions spécifiées et suivant une procédure spécifiée

NOTE 1 La précision est définie dans la CEI 60050-300, définition 311-06-08

NOTE 2 Le terme ô prộcision mesurộe ằ est parfois utilisộ à la place du terme ô imprộcision ằ Il est recommandộ d’éviter cette expression

3.6 erreur différence algébrique entre la valeur indiquée et une valeur comparative de la grandeur mesurée

NOTE L'erreur est positive quand la valeur indiquée est supérieure à la valeur comparative L'erreur est en général exprimée en pourcentage de l'intervalle idéal correspondant

3.7 erreur mesurée valeur positive ou négative la plus élevée de l'erreur de la valeur moyenne, mesurée en montant ou en descendant, à chaque point de mesure

3.8 non-conformité degré de proximité entre une courbe d’étalonnage et une courbe caractéristique spécifiée (par exemple linéaire, logarithmique ou parabolique)

NOTE La non-conformité ne comprend pas l'hystérésis

3.9 non-linéarité écart par rapport à la linéarité

NOTE 1 La linéarité est définie dans la CEI 60050(300), définition 311-06-05

NOTE 2 La non-linéarité ne comprend pas l'hystérésis

3.10 non-répétabilité écart par rapport à la répétabilité

NOTE La répétabilité est définie dans la CEI 60050(300), définition 311-06-06

Hysteresis is the property of a measuring instrument or device to produce different output values for the same input values, depending on the direction in which the inputs are applied.

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3.12 zone d'insensibilité (zone morte) étendue finie de valeurs à l’intérieur de laquelle une variation de la variable d'entrée n'entraợne pas de variation mesurable de la variable de sortie

3.13 temps mort intervalle de temps compris entre l'instant ó l'on provoque une variation d'une grandeur d'entrée et l'instant ó débute la variation subséquente de la variable de sortie

The rise time for a step response is defined as the duration between the moment the output variable, starting from zero, reaches a specified low percentage (such as 10%) of its final steady-state value and the moment it first reaches a specified high percentage (like 90%) of that same value.

Tiêu đề	Process measurement and control devices – General methods and procedures for evaluating performance – Part 2: Tests under reference conditions
Trường học	International Electrotechnical Commission
Chuyên ngành	Electrical and Electronic Technologies
Thể loại	Standards Document
Năm xuất bản	2008
Thành phố	Geneva

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