X

X

4 5 Committee Draft OIML/4CD5CD

Date: 19 November, 201521 October, 

2016

Reference number: -14CD

TC_9_p_1_N005

Supersedes document: R 60-2/4CD

OIML TC 9 : 

Instruments for Measuring Mass and Density Circulated to P- and O-members and 

liaison international bodies and external 

organizations for:

P-members votes and 

comments

O-members and liaison 

comments

by: 28 February, 201627 January, 2017

Title: 

Metrological Regulation for Load Cells

Part 2: Metrological controls and 

performance tests

Marked version

Convener: 

John Barton

National Institute of Standards and 

Technology, 

USA

TITLE OF THE CD (English):

OIML R 60-2

Metrological Regulation for Load Cells

Part 2: Metrological controls and performance tests

TITRLE DU CD (French):

OIML R 60-2

Réglementation métrologique des cellules de pesée

Partie 2: Contrôles métrologiques et essais de performance

Original version in: English

November 2015October 2016 OIML R60-2, Part 1

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Contents

PART 2 METROLOGICAL CONTROLS AND PERFORMANCE TESTS 1

7 METROLOGICAL CONTROLS 1

7.1 LIABILITY TO LEGAL METROLOGICAL CONTROLS 1

7.2 MEASUREMENT STANDARDS 1

8 TYPE EVALUATION 1

8.1 SCOPE 1

8.2 TEST REQUIREMENTS 1

8.3 SELECTION OF SPECIMENS FOR EVALUATION 1

8.4 SELECTION OF LOAD CELLS WITHIN A FAMILY 2

8.5 DOCUMENTATION 4

8.6 EXAMINATIONS 5

8.7 PERFORMANCE TESTS 5

8.8 RULES CONCERNING THE DETERMINATION OF ERRORS 8

8.9 VARIATION OF RESULTS UNDER REFERENCE CONDITIONS 10

8.10 TEST PROCEDURES 10

8.11 TEST SEQUENCE 30

8.12 OIML CERTIFICATE 31

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Part 2 Metrological controls and performance tests

7 Metrological controls 

7.1 Liability to legal metrological controls

7.1.1 Imposition of controls

This Recommendation prescribes performance requirements for load cells used in devices or 

systems subjected to legal metrological control. National legislation may impose metrological 

controls that verify compliance with this Recommendation. Such controls, when imposed, may 

include type evaluation. 

7.2 Measurement standards

The expanded uncertainty, U (for coverage factor k = 2), for the combination of the force-generating 

system and the indicating instrument used during the tests to observe the load cell output shall be 

less than 1/3 times the MPE of the load cell under test. [Guide to the Expression of Uncertainty in 

Measurement, 2008] [7]

8 Type evaluation 

8.1 Scope

This section provides test procedures for type evaluation testing of load cells.

Wherever possible, test procedures have been established to apply as broadly as possible to all load 

cells within the scope of OIML R 60.

The procedures apply to the testing of load cells only. No attempt has been made to cover testing of 

complete systems that include load cells.

8.2 Test requirements 

Test procedures for the type evaluation of load cells are provided in Section 8.7 and the Test Report 

Format is provided in OIML R60 Part 3. Initial and subsequent verification of load cells 

independent of the measuring system in which they are used is normally considered inappropriate if 

the complete system performance is verified by other means.

8.3 Selection of specimens for evaluation

Type evaluation shall be carried out on at least one specimen, which represents the type. The 

evaluation shall consist of the examination and tests specified in 8.6 and 8.7

In case the applicant wants to have approved several versions or measuring ranges, the issuing 

authority decides which version(s) and range(s) shall be supplied.
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If a specimen does not pass a specific test as a result of the design of the type and therefore has to be Right + Not at 18.89 cm

modified, the applicant shall carry out this modification to all the specimens supplied for test. If 

the modification has been applied to all sub-types of the family which have the common design 

defect that required modification, it is then required that the other specimens that have been 

submitted shall be re-tested. Depending upon the modification this may involve a repeat of the 

specific test or a complete re-test.

If during the evaluation the specimen experiences malfunction or breakage that necessitates a repair 

in order to complete the test, the applicant shall verify whether this repair concerns an incident or 

whether a modification will need be made to the design. In the latter case the modification is to be 

applied to all specimens supplied for the test and the applicable documentation to be updated 

accordingly. 

If the issuing authority has reason to believe that a modification or repair could cause a different

outcome for test result(s) than the result(s) which was observed prior to any modification, these tests 

shall be repeated. The reason for repeating a test shall be given within the scope of the test report.

8.3.1 Number of load cells to be tested 

The selection of load cells to be tested shall be such that the number of load cells to be tested is 

minimized. (see practical example in Annex D).

8.4 Selection of load cells within a family

In order to accelerate the test procedure, the testing laboratory may carry out different tests 

simultaneously on different units. In this case, the issuing authority decides which version or 

measuring range will be subjected to a specific test.

All accuracy and influence tests including span stability test for digital load cells, shall be performed 

on the same unit. Disturbance tests on digital load cells may be (simultaneously) carried out on not 

more than 2 additional load cells.

Where a family composed of one or more groups of load cells of various capacities and 

characteristics is presented for type evaluation, the following provisions shall apply.
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When classifying load cells on the basis of the shape design, additional consideration should be 

given to design criteria such as the geometrical characteristics of the areas of the load cell created 

during fabrication. Examples of strain gauge-type load cells with identical outer dimensions but 

different geometries are shown below.

A. difference of geometry in the area of thin places (i.e., round or oval drilling)

B. difference of geometry in the area of fixing/load introduction (i.e., groove, base, offset)

C. difference of geometry in the inner of fixing/load introduction (i.e., drilling, thread,

dropping)

Figure 4. Examples of Strain Gauge-Type Load Cell Design Shapes

8.4.1 Load cells of the same capacity belonging to different groups 

Where load cells of the same family and same capacity belong to different groups, the selection 

of a load cell for testing requires a choice between characteristics of the load cells. In this case, 

the load cell requiring the most onerous tests shall be selected. This selection will result in the 

load cell with the most stringent metrological characteristics being tested.

8.4.2 Load cells with a capacity in between the capacities tested 

Load cells of the same family with a capacity in between the capacities tested, as well as those 

above the largest capacity tested, but not over 5 times the largest capacity tested, may be 

included in the certificate and are deemed to fulfill the requirements of this Recommendation. 

This is under the provision that along with the change of capacity there is no change of 

measurement principle or material used in the construction of the load cell (e.g., from bending 
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beam to shear beam or stainless steel replacing aluminum). Right + Not at 18.89 cm

8.4.3 Smallest capacity load cell from the group 

For any family, the smallest capacity load cell from the group with the best characteristics shall 

be selected for testing. For any group, the smallest capacity load cell in the group shall always 

be selected for test unless that capacity falls within the range of allowed capacities of selected 

load cells having better metrological characteristics according to the requirements of 8.4.1 and 

8.4.2.

8.4.4 Ratio of largest capacity to the nearest smaller capacity 

When the ratio of the largest capacity load cell in each group to the nearest smaller capacity 

having been selected for test is greater than 5, then another load cell shall be selected. The 

selected load cell shall have a capacity between 5 and 10 times that of the nearest smaller 

capacity load cell which has been selected. When no capacity meets this criterion, the selected 

load cell shall be that having the smallest capacity exceeding 10 times that of the nearest smaller 

capacity load cell which has been selected. 

8.4.5 Humidity test 

If more than one load cell of a family has been submitted for testing, only one load cell shall be 

tested for humidity when applicable.

8.4.6 Selection of digital load cells equipped with electronics

For load cells and load cell families equipped with electronics and with an analog to digital 

converter (that does not differ between load cells in the family) all applicable tests shall be 

performed on the load cell with the minimum, μV/vmin as input for the analog to digital 

converter.

(Same principle as OIML R76 [1], Annex C, Table 12)

Notwithstanding this requirement, the criteria for assignment of a load cell to a family and the 

selection of test specimens found in 8.4.1 to 8.4.5 shall be observed.

8.5 Documentation

The documentation submitted with the application for type evaluation shall include:

a) description of its general principle of measurement;

b) mechanical drawings (including documents on the load transmission(s) as per Annex E);

c) electric/electronic diagrams;

d) installation requirements (physical and electrical) if appropriate;

e) operating instructions that shall be provided to the user if appropriate;

f) documents or other evidence to support and demonstrate the manufacturer’s belief that the 

design and characteristics of the load cell will comply with the requirements of this 
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Recommendation; and

g) documentation relative to software if appropriate.

If the testing laboratory deems this necessary, it can require more detailed documentation; either to 

be able to study the quality of the instrument, or to be able to fully define the approved type, or both.

If the manufacturer does not prescribe a specific load transmission it will be the responsibility of the 

test laboratory to decide what kind of load transmission is to be used for testing. (see also Annex E)

8.6 Examinations

Examinations and testing of load cells are intended to verify compliance with the requirements of 

Part 1 of this Recommendation.

The load cell shall be given a visual inspection to obtain a general appraisal of its design and 

construction and the documentation shall be studied.

In particular, the following aspects shall be examined:

a. accuracy classes and their symbols (5.1.1 and 6.2.4.1);

b. maximum number of load cell verification intervals (5.1.2 and 6.2.4.5);

c. load cell measuring ranges (3.5.2);

d. apportioning of errors (5.3.1.1 and 3.7.2);

e. construction of load cells (3.3);

f. software (6.1) (if applicable);

g. inscriptions and presentation of load cell information (6.2); and

h. installation instructions/recommendations.

8.7 Performance Tests

8.7.1 Purpose

The following test procedures for quantitative determination of load cell performance 

characteristics are established to ensure uniform type evaluation. 

8.7.2 Test equipment

The basic equipment for type evaluation tests consists of a force-generating system and a suitable 

indicating instrument, which measures the output of the load cell (see 7.2). 
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8.7.3 Test General considerations for environmental and test conditions Right + Not at 18.89 cm

8.7.3.1 Environmental conditions 

Tests shall be performed under stable environmental conditions. The ambient temperature is 

deemed to be stable when the difference between extreme temperatures noted during the test 

does not exceed one fifth of the temperature range of the load cell under test, without being 

greater than 2 °C.

Conditions involving: electrical power supplies; electromagnetic fields; and radio frequency 

fields are to be measured/controlled when the load cell is being evaluated against the effects 

of these influences, and must also be considered when there is a potential for these types of 

conditions to impart effects on other tests.

8.7.3.2 Acceleration of gravity 

The mass standards used to generate the force applied during testing shall be corrected, if 

necessary, for the site of testing and the value of the gravity constant, g, at the test site shall 

be recorded with the test results. The value of the mass standards used to generate the force 

shall be traceable to the appropriate national or international standard of mass.

8.7.3.3 Loading conditions 

Particular attention shall be paid to loading conditions to prevent the introduction of errors 

not inherent to the load cell. Factors such as surface roughness, flatness, corrosion, 

scratches, eccentricity, etc., should be taken into consideration. Loading conditions shall be 

in accordance with the specifications of the load cell manufacturer. The loads shall be 

applied and removed along the sensitive axis of the load cell without introducing shock to the 

load cell.

Since the aim of this test is not to measure the influence on the metrological performances of 

mounting/dismounting the load cell on/from the force-generating system, the installation of 

the load cell in the force-generating system shall be done with particular care. In addition, 

the installation shall be done with consideration given to the intended use of the load cell and 

the load transmission. The effect on the metrological performance caused by 

mounting/dismounting the load cell on/from the force-generating system should be negligible 

in order to establish the magnitude of the test parameter. If possible, the load cell should not

be dismounted from the force-generation system during the entire period of the test.

8.7.3.4 Measuring range limits 

With consideration to the capability of the force-generating system, the minimum load, Dmin, 

shall be as near as possible to but not less than the minimum dead load, Emin, and shall not be 

higher than a value equal to 10% of Emax. The maximum load, Dmax, shall be not less than 90 

% of Emax, nor shall it be greater than Emax (refer to Fig. 3).
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8.7.3.5 Reference standards 

All standards and measuring instruments used for the tests shall be traceable to national or 

international standards.

8.7.3.6 Stabilization period 

A stabilization period for the load cell under test and the indicating instrument shall be 

provided, as recommended by the manufacturers of the equipment used.

8.7.3.7 Temperature conditions 

It is important to allow sufficient time for temperature stabilization of the load cell to be 

achieved. Particular attention shall be devoted to this requirement for large load cells. The 

loading system shall be of a design which will not introduce significant thermal gradients 

within the load cell. The load cell and its connecting means (cables, tubes, etc.) which are 

integral or contiguous shall be at the same test temperature. The indicating instrument shall 

be maintained at room temperature. The temperature effect on auxiliary connecting means 

shall be considered in determining results.

8.7.3.8 Barometric pressure effects 

Where changes in barometric pressure may significantly affect the load cell output, such 

changes shall be considered.

 

8.7.3.9 Humidity effects

When a load cell is marked with the symbol CH or is not marked with a humidity symbol, it 

shall be subjected to the humidity test, as specified in 8.10.5.

When a load cell is marked with the symbol SH, it shall be subjected to the humidity test, as 

specified in 8.10.6

Load cells marked with the symbol NH shall not be subjected to the humidity tests as 

described in 8.10.5 and 8.10.6. 

8.7.3.10 Indicating instrument checking 

Some indicating instruments are provided with a convenient means for checking the 

indicating instrument itself. When such features are provided, they shall be utilized 

frequently to ensure that the indicating instrument is within the accuracy required by the test 

being performed. Periodic checks on the calibration status of the indicating instrument shall 

be performed. 

8.7.3.11 Other conditions 

Other conditions specified by the manufacturer such as input/output voltage, electrical 

sensitivity, input impedance of the indicator, etc. shall be taken into consideration during the 

test(s).
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8.7.3.12 Time and date format Right + Not at 18.89 cm

All time and date points shall be recorded such that the data can later be presented in test 

reports in absolute, not relative, units of local time and date. The date shall be recorded in 

the ISO 8601 [9] (Representation of dates and times) format of ccyy-mm-dd. 

Note: “cc” may be omitted in cases where there is no possible confusion as to the century.

8.7.4 Error under rated operating conditions

The type of load cell is presumed to comply with the provisions specified in 5.3 to 5.5 of this 

Recommendation, if it passes the tests (in 8.10), confirming that the error of the measuring 

instrument does not exceed the maximum permissible error specified in 5.3.1 under the 

conditions in 8.7.3.

8.8 Rules concerning the determination of errors

8.8.1 Conditions

The limits of error shown in Table 4 shall apply to all load cell measuring ranges complying with 

the following conditions: 

n ≤ nmax

v ≥ vmin

8.8.2 Limits of error 

The limits of error shown in Table 4 shall refer to the error envelope defined in 2.2 and 5.3.1.12

which is referenced to the straight line that passes through the minimum load output and the load 

cell output for a load of 75 % of the measuring range taken on ascending load at 20 °C. This is 

based upon the initial 20 °C load test. See Part 3 (Test Report Format for Type Evaluation). 

8.8.3 Initial readings 

During the conduct of the tests, the initial reading shall be taken at a time interval after the 

initiation of loading or unloading, whichever is applicable, as specified in Table 7.
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Change in load Time Allowed for Loading and Stabilization:

Greater than Up to and 

including Classes C&D Class B Class A

0 kg 10 kg 10 seconds 15 Seconds 20 Seconds

10 kg 100 kg 20 seconds 30 Seconds 40 Seconds

100 kg 1 000 kg 30 seconds 45 Seconds 60 Seconds

1 000 kg 10 000 kg 40 seconds 60 Seconds 80 Seconds

10 000 kg 100 000 kg 50 seconds 75 Seconds 100 Seconds

100 000 kg 60 seconds 90 Seconds 120 Seconds

Table 7.

Combined Loading and Stabilization Times to be Achieved Prior to Reading

8.8.3.1 Loading/unloading times 

The loading or unloading times shall be approximately half the time specified in Table 7. 

The remaining time shall be utilized for stabilization. The tests shall be conducted under 

constant conditions. The loading or unloading time and the stabilizing time shall be recorded

in the test report in absolute, not relative values. 

8.8.3.2 Adherence to loading/unloading times 

When the specified loading or unloading times cannot be achieved, the applicant for 

evaluation should be consulted and the following shall apply.

a) In the case of the minimum dead load output return test, the time may be increased from 

100 % to a limit of 150 % of the specified time provided that the permissible variation 

of the result is proportionally reduced from 100 % to 50 % of the allowable difference 

between the initial reading of the minimum load output upon unloading and the reading 

before loading. 

For example:

(1). A change in load of 10 kg for class C&D load cells, loading (or unloading) time

(approximately 5 s) is increased to 7.5 seconds (150% of 5 s), MPE is reduced to 

50%; or

(2). A change in load of 1500 kg for class C&D load cells, loading (or unloading) time

(approximately 20 s) is increased to 25 seconds (125% of 20 seconds), MPE is 

reduced to 75%.

b) In all cases, the actual times shall be recorded in the Test Report.
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Formatted: Tab stops: 17.78 cm,

8.9 Variation of results under reference conditions Right + Not at 18.89 cm

8.9.1 Creep 

A load of Dmax shall be applied as specified in 8.10.2.1 – 8.10.2.7 at which time an initial reading 

shall be taken. Variation between the initial reading and subsequent readings of the load Dmax,

taken as specified in 8.10.2.8 shall comply with the limits specified in 5.5.1

8.9.2 Minimum dead load output return

The difference between an initial reading at a load of Dmin (as specified in 8.10.3.1 – 8.10.3.6) 

and a subsequent reading also of Dmin (taken after the application of a load of Dmax as specified in 

8.10.3.7 – 8.10.3.10) shall not exceed the value in specified in 5.5.2.

8.10 Test procedures

Each of the tests below is presented as a “stand alone” individual test. However, for the efficient 

conduct of the load cell tests, it is acceptable that the increasing and decreasing load, creep, 

repeatability, and minimum dead load output return tests can be conducted concurrently at the given 

test temperature before changing to the next test temperature (see 8.11, Figures 5 and 6). The 

barometric pressure and the humidity tests are conducted individually following completion of the 

above tests.

8.10.1 Determination of measurement error, repeatability error and temperature effect on 

minimum dead load output. 

This test is applied to verify compliance with the provisions in 5.3, 5.4, and 5.6.1.3.

8.10.1.1 Check test conditions 

Refer to the test conditions in 8.7.3 to ensure that proper consideration has been given to 

those conditions, prior to performing the following tests.

8.10.1.2 Insert load cell

Insert the load cell into the force-generating system, load to the minimum test load, Dmin, and 

stabilize at 20 °C (± 2 °C). 

8.10.1.3 Preload load cell 

Preload the load cell by applying the maximum test load, Dmax, three times, returning to the 

minimum test load, Dmin, after each load application. Wait 5 minutes before commencing 

with further tests.

8.10.1.4 Check indicating instrument

Check the indicating instrument according to 8.7.3.10.
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8.10.1.5 Monitor load cell

Monitor the minimum test load output until stable. 

8.10.1.6 Record indication

Record the indicating instrument indication at the minimum test load, Dmin.

8.10.1.7 Test load points 

All test load points in a loading and unloading sequence shall be spaced at approximately 

equal time intervals. The readings shall be taken at time intervals as near as possible to those 

specified in Table 7 in 8.8.3. These two time intervals shall be recorded.

8.10.1.8 Apply loads 

Apply increasing loads up to the maximum test load, Dmax. There shall be at least five 

increasing load points, which shall include values at or near those at which the maximum 

permissible error changes, as listed in Table 4 in 5.3.1.12.

8.10.1.9 Record indications 

Record the indicating instrument indications at time intervals as near as possible to those 

specified in Table 7 in 8.8.3. These two time intervals shall be recorded.

8.10.1.10 Decrease test loads 

Decrease the test loads to the minimum test load, Dmin, using the same load points as 

described in 8.10.1.8.

8.10.1.11 Record indications 

Record the indicating instrument indications at time intervals as near as possible to those 

specified in Table 7 in 8.8.3. These two time intervals shall be recorded. 

8.10.1.12 Repeat procedures for different accuracy classes

Repeat the operations described in 8.10.1.7 to 8.10.1.11 four more times for accuracy classes 

A and B or two more times for accuracy classes C and D.

8.10.1.13 Repeat procedures for different temperatures

Repeat the operations described in 8.10.1.3 to 8.10.1.12, first at the higher temperature, then 

at the lower temperature, in accordance with 5.6.1; then perform the operations in 8.10.1.3 to 

8.10.1.12 at 20 °C (± 2 °C).
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8.10.1.14 Determine magnitude of measurement error Right + Not at 18.89 cm

The magnitude of the measurement error shall be determined based on the average of the 

results of the tests conducted at each temperature level and compared with the maximum 

permissible measurement errors in 5.3.2 (see Table 4).

8.10.1.15 Determine repeatability error

From the resulting data, the repeatability error may be determined and compared with the 

limits specified in 5.4.

8.10.1.16 Determine temperature effect on minimum dead load output

From the resulting data, the temperature effect on minimum dead load output may be 

determined and compared with the limits specified in 5.6.1.3.

8.10.2 Determination of creep error. 

This test is applied to verify compliance with the provisions in 5.5.1. 

8.10.2.1 Check test conditions

Refer to the test conditions in 8.7.3 to ensure that proper consideration has been given to 

those conditions prior to performing the following tests. 

8.10.2.2 Insert load cell

Insert the load cell into the force-generating system, load to the minimum test load, Dmin, and 

stabilize at 20 °C (± 2 °C).

8.10.2.3 Preload load cell

Preload the load cell by applying the maximum test load, Dmax, three times, returning to the 

minimum test load, Dmin, after each load application. Wait one hour.

8.10.2.4 Check indicating instrument

Check the indicating instrument according to 8.7.3.10.

8.10.2.5 Monitor load cell

Monitor the minimum test load output until stable.

8.10.2.6 Record indication

Record the indicating instrument indication at the minimum test load, Dmin.
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8.10.2.7 Apply load

Apply a constant maximum test load, Dmax (between 90% and 100% of Emax).

8.10.2.8 Record indications

Record the initial indicating instrument indication at the time intervals specified in Table 7 in 

8.8.3. Continue to record periodically thereafter, at recorded time intervals over a 30-minute 

period, ensuring that a reading is taken at 20 minutes. 

8.10.2.9 Repeat procedures for different temperatures

Repeat the operations described in 8.10.2.3 to 8.10.2.8, first at the higher temperature, then at 

the lower temperature, in accordance with 5.6.1. 

8.10.2.10 Determine creep error

With the resulting data, and taking into account the effect of barometric pressure changes 

according to 8.7.3.7, the magnitude of the creep error can be determined and compared with 

the permissible variation specified in 5.5.1.

8.10.3 Determination of minimum dead load output return (DR)

This test is applied to verify compliance with the provisions in 5.5.2.

8.10.3.1 Check test conditions 

Refer to the test conditions in 8.7.3 to ensure that proper consideration has been given to 

those conditions prior to performing the following test.

8.10.3.2 Insert load cell

Insert the load cell into the force-generating system, load to the minimum test load, Dmin, and 

stabilize at 20 °C (± 2 °C).

8.10.3.3 Preload load cell

Preload the load cell by applying the maximum test load, Dmax, three times, returning to the 

minimum test load, Dmin, after each load application. Wait one hour before commencing any 

further tests. 

8.10.3.4 Check indicating instrument

Check the indicating instrument according to 8.7.3.10.

8.10.3.5 Monitor load cell

Monitor the minimum test load output until stable. 
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8.10.3.6 Record indication Right + Not at 18.89 cm

Record the indicating instrument indication at the minimum test load, Dmin. 

8.10.3.7 Apply load 

Apply a constant maximum test load, Dmax (between 90% and 100% of Emax). 

8.10.3.8 Record indications 

Record the initial indicating instrument indication at time intervals as near as possible to

those specified in Table 7 in 8.8.3. These two time intervals shall be recorded. Record the 

time at which the load is fully applied and maintain the load for a 30-minute period. 

8.10.3.9 Record data

Record the time of initiation of unloading and return to the minimum test load, Dmin. 

8.10.3.10 Record indication

Record the indicating instrument indication at time intervals as near as possible to those 

specified in Table 7 in 8.8.3. These two time intervals shall be recorded. 

8.10.3.11 Repeat procedures for different temperatures

Repeat the operations described in 8.10.3.3 to 8.10.3.10, first at the higher temperature, then 

at the lower temperature in accordance with 5.6.1.

8.10.3.12 Determine minimum dead load output return (DR)

With the resulting data, the magnitude of the minimum dead load output return (DR) can be 

determined and compared with the permissible variation specified in 8.9.2.

8.10.4 Determination of barometric pressure effects (Atmospheric pressure). 

This test is applied to verify compliance with the provisions in 5.6.2.

This test shall be conducted unless there is sufficient design justification to show that the load 

cell performance is not affected by changes in barometric pressure. The justification for not 

conducting this test shall be noted in the test report.

8.10.4.1 Check test conditions 

Refer to the test conditions in 8.7.3 to ensure that proper consideration has been given to 

those conditions prior to performing the following test.

8.10.4.2 Insert load cell 

At room temperature, insert the unloaded load cell into the pressure chamber at atmospheric 

pressure. 
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8.10.4.3 Check indicating instrument

Check the indicating instrument according to 8.7.3.10.

8.10.4.4 Monitor load cell

Monitor the output until stable. 

8.10.4.5 Record indication

Record the indicating instrument indication.

8.10.4.6 Change barometric pressure

Change the barometric pressure by a minimum of 1 kPa greater than atmospheric pressure 

and record the indicating instrument indication. 

8.10.4.7 Determine barometric pressure error

With the resulting data, the magnitude of the barometric pressure influence can be 

determined and compared with the limits specified in 5.6.2.

8.10.5 Determination of humidity effects for load cells marked CH or not marked.

This test is applied to verify compliance with the provisions in 5.6.3.1.

8.10.5.1 Check test conditions

Refer to the test conditions in 8.7.3 to ensure that proper consideration has been given to 

those conditions prior to performing the following test. 

8.10.5.2 Insert load cell

Insert the load cell into the force-generating system, load to the minimum test load, Dmin, and 

stabilize at 20 °C (± 2 °C).

8.10.5.3 Preload load cell 

Preload the load cell by applying the maximum test load, Dmax, three times, returning to the 

minimum test load, Dmin, after each application. Wait 5 minutes before commencing any 

further tests.

8.10.5.4 Check indicating instrument 

Check the indicating instrument according to 8.7.3.10.

8.10.5.5 Monitor load cell 

Monitor the minimum test load output until stable.

8.10.5.6 Record indication 

Record the indicating instrument indication at the minimum test load, Dmin.
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Formatted: Tab stops: 17.78 cm,

8.10.5.7 Apply load Right + Not at 18.89 cm

Apply a maximum test load, Dmax.

8.10.5.8 Record indications 

Record the initial indicating instrument indication at time intervals as near as possible to 

those specified in Table 7 in 8.8.3. These two time intervals shall be recorded.

8.10.5.9 Remove load 

Remove the test load to the minimum test load, Dmin.

8.10.5.10 Record indication

Record the indicating instrument indication at time intervals as near as possible to those 

specified in Table 7 in 8.8.3. These two time intervals shall be recorded.

8.10.5.11 Repeat procedures for different accuracy classes

Repeat the operations described in 8.10.5.7 to 8.10.5.10 four more times for accuracy classes 

A and B or two more times for accuracy classes C and D.

8.10.5.12 Conduct damp heat, cyclic test (CH)

This test is conducted to verify compliance with the provisions in 5.6.3.1 under conditions of 

high humidity combined with cyclic temperature changes

Applicable standards:

IEC 60068-2-30 [10]: Environmental testing Part 2: Tests. 

Test Db and guidance: Damp heat cyclic (12 + 12-hour) cycle

IEC 60068-3-4 [11]: Environmental testing - Part 2: Tests. Guidance for damp heat tests.
November 2015October 2016 OIML R60-21

2-17

Test method Exposure to damp heat with cyclic temperature variation

Test conditions The relative humidity is between 80 % and 96 % and the temperature is 

varied from 25 °C to 40 °C, in accordance with the specified cycle. 

Preconditioning of load cell

Load cell placed in the chamber with the output connection external to the 

chamber, and switched off. 

Use variant 2 of IEC 60068-2-30 Ed. 3.0 (2005-08) when lowering the 

temperature.

Initial measurements Made according to 8.10.5.1 - 8.10.5.11

Test procedure in brief

This test consists of exposure to 12 temperature cycles of 24-hour duration 

each. 

Condensation is expected to occur on the load cell during the temperature 

rise.

The 24 h cycle comprises:

1) temperature rise during 3 hours,

2) temperature maintained at upper value until 12 hours from the start of the 

cycle,

3) temperature lowered to lower temperature level within a period of 3 to 6 

hours, the declination (rate of fall) during the first hour and a half being 

such that the lower temperature level would be reached in a 3 hours

period,

4) temperature maintained at the lower level until the 24 h period is 

completed.

The stabilizing period before and recovery period after the cyclic exposure 

shall be such that the temperature of all parts of the load cell is within 3 °C of 

its final value.

Recovery conditions and final measurements: According to 8.10.5.13 –

8.10.5.15.

 

8.10.5.13 Remove load cell from chamber 

Remove the load cell from the humidity chamber, carefully remove surface moisture, and 

maintain the load cell at standard atmospheric conditions for a period sufficient to attain 

temperature stability (normally 1 to 2 hours). 

8.10.5.14 Repeat test procedures

Repeat 8.10.5.1 to 8.10.5.11 ensuring that the minimum test load, Dmin, and the maximum 

test load, Dmax, applied are the same as previously used.

8.10.5.15 Determine the magnitude of humidity-induced variations 

The difference between the average of the reading of the minimum load output and of the 

maximum output attributed to cyclic changes in humidity as determined using test procedures 

in 8.10.5 shall not exceed the limits specified in 5.3.1.1

The difference between the average of the reading of the maximum load, Dmax, attributed to 

cyclic changes in humidity as determined using test procedures in 8.10.5 shall not exceed the 
OIML R60-2 October 2016

November 2015

2-18

Formatted: Tab stops: 17.78 cm,

limits specified in 6.3.1.1 Right + Not at 18.89 cm

8.10.6 Determination of humidity effects for load cells marked SH.

This test is applied to verify compliance with the provisions in 5.6.3.2. 

8.10.6.1 Check test conditions 

Refer to the test conditions in 8.7.3 to ensure that proper consideration has been given to 

those conditions prior to performing the following tests. 

8.10.6.2 Insert load cell 

Insert the load cell into the force-generating system, load to the minimum test load, Dmin, and 

stabilize at 20 °C (± 2 °C ). 

8.10.6.3 Preload load cell 

Preload the load cell by applying the maximum test load, Dmax, three times, returning to the 

minimum test load, Dmin, after each load application. Wait 5 minutes before commencing any 

further tests.

8.10.6.4 Check indicating instrument 

Check the indicating instrument according to 8.7.3.10.

8.10.6.5 Monitor load cell 

Monitor the minimum test load output until stable. 

8.10.6.6 Record indication 

Record the indicating instrument indication at the minimum test load, Dmin. 

8.10.6.7 Test load points 

All test load points in a loading and unloading sequence shall be spaced at approximately 

equal time intervals. The readings shall be taken at time intervals as near as possible to those 

specified in Table 7 in 8.8.3. These two time intervals shall be recorded.

8.10.6.8 Apply loads 

Apply increasing loads up to the maximum test load, Dmax. There shall be at least five 

increasing load points which shall include loads approximating to the highest values in the 

applicable steps of maximum permissible measurement errors, as listed in Table 4 in 

5.3.1.12.

8.10.6.9 Record indications 

Record the indicating instrument indications at time intervals as near as possible to those 

specified in Table 7 in 8.8.3. These two time intervals shall be recorded. 
November 2015October 2016 OIML R60-21

2-19

8.10.6.10 Decrease load 

Decrease the test load to the minimum test load, Dmin, using the same load points as 

described in 8.10.6.8.

8.10.6.11 Conduct damp heat, steady state test 

This test is conducted to verify compliance with the provisions in 5.6.1 or 5.6.3 under 

conditions of high humidity and constant temperature.

Applicable standards:

IEC 60068-2-78: Environmental testing ¬Part 2: Tests. Test Ca: Damp heat, steady state, 

Environmental testing - Part 2: Tests. Test Cb: Damp heat, steady state, primarily for 

equipment. [12]

IEC 60068-3-4: Environmental testing - Part 2: Tests. Guidance for damp heat tests. [11]

Test method Exposure to damp heat in steady state

Test conditions Relative humidity of 85 %

Preconditioning of load cell Place the load cell in the chamber with the output connection external 

to the chamber, and switched on.

Test procedure in brief

This test involves exposure of the load cell to a constant temperature and a 

constant relative humidity. The load cell shall be tested as specified in 

8.10.6.1 to 8.10.6.10: 

a) at a reference temperature (20 °C or the mean value of the temperature 

range whenever 20 °C is outside this range) and a relative humidity of 

50 % following conditioning;

b) at the high temperature of the range specified in 5.6.1 for the load cell 

and a relative humidity of 85 %, 48 hours following temperature and 

humidity stabilization; and 

c) at the reference temperature and relative humidity of 50 %.

The load cell shall be handled such that no condensation of water occurs on 

it.

8.10.6.12 Recording indications 

Record the indicating instrument indications at time intervals as near as possible to those 

specified in Table 7 in 8.8.3. These two time intervals shall be recorded. 

8.10.6.13 Determine the magnitude of humidity-induced variations 

With the resulting data, the magnitude of humidity-induced variations can be determined and 

compared with the limits specified in 5.6.3.2. 

8.10.7 Additional test for digital load cells equipped with electronics (Disturbances).

These tests are applied to verify compliance with the provisions in 5.7.2.1, and 5.7.2.2.
OIML R60-2 October 2016

November 2015

2-20

Formatted: Tab stops: 17.78 cm,

8.10.7.1 Performance and stability tests Right + Not at 18.89 cm

A load cell equipped with electronicsdigital load cell shall pass the performance and stability

tests according to 8.10.7.2 to 8.10.7.10 11 for the tests given in Table 5. 

8.10.7.2 Evaluation of error for digital load cells 

For load cells possessing a digital output interval greater than 0.20v, the changeover points 

are to be used in the evaluation of errors, prior to rounding as follows. At a certain load, L, 

the digital output value, I, is noted. Additional loads, for example 0.1 v, are successively 

added until the output of the load cell is increased unambiguously by one digital output 

increment (I + v). The additional amount of load, Δ L, added to the load cell gives the digital 

output value prior to rounding, P, by using the following formula: 

P = I + 1/2 v – Δ L

where: 

I = the indication or digital output value;

v = the load cell verification interval; and 

Δ L = additional load added to the load cell. 

The error, E, prior to rounding is:

E = P – L = I + 1/2 v – ΔL – L

and the corrected error, Ec

, prior to rounding is: 

EC = E – EO ≤ MPE

where EO is the error calculated at the minimum test load, Dmin. 

8.10.7.3 Warm-up time 

Test procedure in brief: 

Stabilize the load cell at 20 °C (± 2 °C) and disconnect from any electrical supply for a 

period of at least 8 hours prior to the test. 

Insert the load cell into the force-generating system. 

Preload the load cell by applying a maximum test load, Dmax, then, returning to the minimum 

test load, Dmin, three times.

Allow the load cell to rest for 5 minutes. Connect the load cell to the power supply and 

switch on.

Record data:

As soon as a measurement result can be obtained, record the minimum test load output and 

the maximum test load, Dmax, applied.
November 2015October 2016 OIML R60-21

2-21

Loading and unloading:

The maximum test load output shall be determined at time intervals as close as possible to 

those specified in Table 7 in 8.8.3 and recorded and the load should be returned to the 

minimum test load, Dmin. These measurements shall be repeated after 5, 15 and 30 minutes. 

For load cells of class A, the provisions of the operating manual for the time following 

connection to electrical supply shall be observed.

8.10.7.4 Power voltage variations 

This test is applied to verify compliance with 5.7.2.2, 5.7.2.3, and 5.7.2.4 under conditions of 

variations in voltage to the load cell’s power supply.

Applicable standards:

For load cells powered by AC mains: IEC/TR3 61000-2-1 [13], IEC 61000-4-1 (set-up)

[14]

For load cells powered by DC mains: IEC 61000-4-29 [15], IEC 61000-4-1 (set-up) [14]

Test method Subject load cell to variations of power supply voltage

Test conditions In accordance with 8.7.3.1 Environmental conditions

Preconditioning of load cell Stabilize load cell under constant environmental conditions

Test level

Mains power voltage variations*:

upper voltage limit (V + 10%);

lower voltage limit (V – 15%)

Battery power voltage variations:

- upper voltage limit (not applicable);

- lower power voltage: (specified by the manufacturer, below V)

The voltage, (V) is the value specified by the manufacturer. If a range of 

reference mains power voltage (Vmin, Vmax) is specified, then the test shall be 

performed at an upper voltage limit of Vmax and a lower voltage limit of Vmin.

Test procedure in brief

This test consists of subjecting the load cell to variations of power voltage.

A load test is performed in accordance with 8.10.1.1 to 8.10.1.12 at 20°C (± 

2 °C), with the load cell powered at reference voltage. The test is repeated 

with the load cell powered at the upper limit and at the lower limit of power 

voltage.

8.10.7.5 Short-time power reductions (see 5.7.2.5 Disturbances)

This test is conducted to verify compliance with 5.7.2.2, 5.7.2.3, and 5.7.2.4 under conditions 

of short-time power reductions

Applicable standards:

For load cells powered by DC mains: IEC 61000-4-29 [15]; IEC 61000-4-1 [14]
OIML R60-2 October 2016

November 2015

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Formatted: Tab stops: 17.78 cm,

For load cells powered by AC mains; IEC 61000-4-11 [16]; IEC 61000-6-1 [17]; IEC Right + Not at 18.89 cm

61000-6-2 [18]

Test method Expose load cell to specified short-timer power reductions

Test conditions In accordance with 8.7.3.1 Environmental conditions

Preconditioning of load cell Stabilize load cell under constant environmental conditions

Test level

Reduction: 100 % 50 %

Number of half cycles: 1 2

Test procedure in brief

A test generator capable of reducing the amplitude of one or more half 

cycles (at zero crossings) of the AC mains voltage shall be used. The test 

generator shall be adjusted before connecting to the load cell. The load cell 

shall be exposed to short interruptions of power. The mains voltage 

reductions shall be repeated ten times at intervals of at least 10 seconds.

Notes

If test is conducted while load cell is installed as a component in a weighing 

instrument, then during the test, the effect of any automatic zero-setting or 

zero-tracking features (if applicable) shall be switched off or suppressed, for 

example by applying a small test load. The test load need not be greater than 

necessary to accomplish this suppression.

8.10.7.6 Bursts (electrical fast transients) (see 5.7.2.5 Disturbances)

This test is conducted to verify compliance with the provisions in 5.7.2.5 during conditions 

where electrical bursts are superimposed on the mains voltage

Applicable standards:

IEC 61000-4-4 [19]: No. 8 (Test procedure), No. 7 (Test set-up), No. 6 (Test 

instrumentation), No. 5 (Test severity).
November 2015October 2016 OIML R60-21

2-23

Test method Introducing transients on the mains power lines

Test conditions In accordance with 8.7.3.1 Environmental conditions

Preconditioning of load cell Stabilize load cell under constant environmental conditions

Test level

Level 2 in accordance with referenced standard: IEC 61000-4-4 No.5

Open circuit output test voltage for: 

• power supply lines: 1 kV; 

• I/O signal, data, and control lines: 0.5 kV. 

Test procedure in brief

This test consists of exposing the load cell to specified bursts of voltage 

spikes.

A burst generator as defined in the referred standard [IEC 61000-4-4 Ed 3.0.

(1995-012012-04) No. 6] shall be used. The characteristics of the generator 

shall be verified before connecting the EUT.

The test shall be applied separately to:

a) power supply lines;

b) I/O circuits and communication lines, if any.

Notes

Test Load:

If test is conducted while load cell is installed as a component in a weighing 

instrument, then during the test, the effect of any automatic zero-setting or 

zero-tracking features (if applicable) shall be switched off or suppressed, for 

example by applying a small test load. The test load need not be greater than 

necessary to accomplish this suppression.

8.10.7.7 Surge (see 5.7.2.5 Disturbances)

This test is conducted to verify compliance with the provisions in 5.7.2.5 during conditions 

where electrical surges are superimposed on the mains voltage and I/O and communication 

ports.

Applicable standards:

IEC 61000-4-5 [20]
OIML R60-2 October 2016

November 2015

2-24

Formatted: Tab stops: 17.78 cm,

Right + Not at 18.89 cm

Test method Exposing the load cell(s) to electrical surges on the mains power lines or on

signal, data and control lines

Test conditions In accordance with 8.7.3.1 Environmental conditions

Preconditioning of load cell Stabilize load cell under constant environmental conditions

Test level

Level 2

Amplitude (peak value) Power supply lines: 0.5 kV (line to line) and 1 kV 

(line to earth)

Test load The test shall be performed with one small test load.

Test procedure in brief

This test is only applicable in those cases where, based on typical situations 

of installation, the risk of a significant influence of surges can be expected. 

This is especially relevant in cases of outdoor installations and/or indoor 

installations connected to long signal lines (lines longer than 30 m or those 

lines partially or fully installed outside the buildings regardless of their 

length).

This test shall be conducted unless there is justification provided regarding 

the specific details of the intended use and installation which would render 

this test unnecessary. The justification for not conducting this test shall be 

noted in the test report.

The test is applicable to power lines, communication lines (internet, dial up 

modem, etc.), and other lines for control, data or signal mentioned above 

(lines to temperature sensors, gas or liquid flow sensors, etc.).

It is also applicable to DC powered load cells where the (excitation) power 

supply comes directly from DC mains.

The test consists of exposing the load cell to surges for which the rise time, 

pulse width, peak values of the output voltage/current on high/low 

impedance load and minimum time interval between two successive pulses 

are defined in the referenced standard. The characteristics of the generator 

shall be adjusted before connecting the load cell.

The test shall be applied to power supply lines, communication lines 

(internet, dial-up modem, etc.), and other lines for control, data or signal 

mentioned above (lines to temperature sensors, gas or liquid flow sensors, 

etc.).

On AC mains supply lines at least 3 positive and 3 negative surges shall be 

applied synchronously with AC supply voltage in angles 0°, 90°, 180° and 

270°. On any other kind of power supply, at least three positive and three 

negative surges shall be applied.

Notes

Both positive and negative polarity of the surges shall be applied.

The duration of the test shall not be less than one minute for each amplitude 

and polarity. 

The injection network on the mains shall contain blocking filters to prevent 

the surge energy being dissipated in the mains.

If test is conducted while load cell is installed as a component in a weighing 

instrument, then during the test, the effect of any automatic zero-setting or 

zero-tracking features (if applicable) shall be switched off or suppressed, for 

example by applying a small test load.
November 2015October 2016 OIML R60-21

2-25

8.10.7.8 Electrostatic discharge (see 5.7.2.5 Disturbances)

This test is conducted to verify compliance with the provisions in 5.7.2.5 in case of direct 

exposure to electrostatic discharges or such discharges in the neighbourhood of the load cell

Applicable standard:

IEC 61000-4-2 [21]: No. 6 (test generator), No. 7 (set-up), No. 8 (test procedure).
OIML R60-2 October 2016

November 2015

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Formatted: Tab stops: 17.78 cm,

Right + Not at 18.89 cm Test method Exposure to electrostatic discharge (ESD)

Test conditions In accordance with 8.7.3.1 Environmental conditions

Preconditioning of the 

load cell Stabilize the load cell under constant environmental conditions

Test procedure in brief

The test comprises exposure of the load cell to electrical discharges.

An ESD generator as defined in the referred standard shall be used and the test 

set-up shall comply with the dimensions, materials used and conditions as 

specified in the referred standard. Before starting the tests, the performance of 

the generator shall be verified.

At least 10 discharges per preselected discharge location shall be applied. The 

time interval between successive discharges shall be at least 10 seconds.

This test includes the paint penetration method, if appropriate; 

For direct discharges, the air discharge shall be used where the contact discharge 

method cannot be applied.

Contact discharge is the preferred test method. Air discharge is far less defined 

and reproducible and therefore shall be used only where contact discharge cannot 

be applied.

Direct application:

In the contact discharge mode to be carried out on conductive surfaces, the 

electrode shall be in contact with the EUT before activation of the discharge. In 

such case the discharge spark occurs in the vacuum relays of the contact 

discharge tip. 

On insulated surfaces only the air discharge mode can be applied. The load cell is 

approached by the charged electrode until a spark discharge occurs 

Indirect application:

The discharges are applied in the contact mode only on coupling planes mounted 

in the vicinity of the load cell.

For load cells not equipped with a ground terminal, the load cell shall be fully 

discharged between discharges.

Test severity

Level 3 (in accordance with IEC 61000-4-2 (2008-12) Ed 2.0 Consolidated 

edition, No. 5). DC voltage up to and including 6 kV for contact discharges and 

8 kV for air discharges. 

Notes

If test is conducted while load cell is installed as a component in a weighing 

instrument, then during the test, the effect of any automatic zero-setting or zerotracking features shall be switched off or suppressed (if applicable), for example 

by applying a small test load. The test load applied during this test need not be 

greater than necessary to accomplish this suppression.

8.10.7.9 Exposure to radiated RF electromagnetic fields (see 5.7.2.5 Disturbances)

This test is conducted to verify compliance with the provisions in 5.7.2.5 under conditions of 

exposure to electromagnetic fields
November 2015October 2016 OIML R60-21

2-27

Applicable standard:

IEC 61000-4-3 [22]: No. 6 (test generator), No. 7 (test set-up), No. 8 (test procedure)

Test method Exposure to specified electromagnetic fields

Test conditions In accordance with 8.7.3.1 Environmental conditions

Preconditioning of the 

load cell Stabilize the load cell under constant environmental conditions.

Test procedure in brief

The load cell is exposed to electromagnetic fields with the required field strength 

and the field uniformity as defined in the referred standard.

The level of field strength specified refers to the field generated by the 

unmodulated carrier wave.

The load cell shall be exposed to the modulated wave field. The frequency sweep 

shall be made only pausing to adjust the RF signal level or to switch RFgenerators, amplifiers and antennas if necessary. Where the frequency range is 

swept incrementally, the step size shall not exceed 1 % of the preceding 

frequency value.

The dwell time of the amplitude modulated carrier at each frequency shall not be 

less than the time necessary for the load cell to be exercised and to respond, but 

shall in no case be less than 0.5 s. 

Adequate EM fields can be generated in facilities of different type and set-up the 

use of which is limited by the dimensions of the load cell and the frequency 

range of the facility.

Test levels

Level 2: 

Frequency range: 80 MHz* to 2 000 MHz;

Field strength: 10 V/m; 

Modulation: 80 % AM, 1 kHz sine wave.

Notes

* Frequency range used in conventional testing shall be 80 MHZ to 2 000 MHZ, 

for load cells with power lines or I/O ports. The lower limit of frequency of 

electromagnetic field is 26 MHz for load cells without power lines or I/O ports, 

and for which the test for conducted electromagnetic field (98.10.7.10) is 

inapplicable.

If test is conducted while load cell is installed as a component in a weighing 

instrument, then during the test, the effect of any automatic zero-setting or zerotracking features enabled (if applicable) through the weighing instrument shall be 

switched off or suppressed, for example by applying a small test load. The test 

load need not be greater than necessary to accomplish this suppression.

8.10.7.10 Exposure to conducted (common mode) currents generated by RF EM fields (see 

5.7.2.5 Disturbances)

This test is conducted to verify compliance with the provisions in 5.7.2.5 while exposed to 

electromagnetic fields

Applicable standard: IEC 61000-4-6 [23]
OIML R60-2 October 2016

November 2015

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Formatted: Tab stops: 17.78 cm,

Right + Not at 18.89 cm

Test method Exposure of the the load cell to disturbances induced by radiated radio-frequency 

fields.

Test conditions In accordance with 8.7.3.1 Environmental conditions

Preconditioning of the 

load cell Stabilize the load cell under constant environmental conditions.

Test procedure in brief

A RF EM current, simulating the influence of EM fields shall be coupled or 

injected into the power ports and I/O ports of the load cell using 

coupling/decoupling devices as defined in the referred standard.

The characteristics of the test equipment consisting of an RF generator,

(de-)coupling devices, attenuators, etc. shall be verified before connecting the 

load cell.

Test load The test shall be performed with one small test load only (10 3 v).

Test level index

Level 2 (in accordance with the referred standard)

Frequency range: 0.15 MHz-80 MHz 

RF amplitude (50 Ω): 10 3 V (emf) 

Modulation: 80 % AM, 1 kHz, sine wave

Notes

This test is not applicable for load cells without mains power supply or other 

input port.

If test is conducted while load cell is installed as a component in a weighing 

instrument, then during the test, the effect of any automatic zero-setting or zerotracking features enabled (if applicable) through the weighing instrument shall be 

switched off or suppressed, for example by applying a small test load. The test 

load need not be greater than necessary to accomplish this suppression.

8.10.7.11 Span stability (see 5.7.2.6) (not applicable to class A load cells) 

Test procedure in brief: 

The test consists in observing the variations of the output of the load cell under reasonably 

constant (±2 °C °) conditions (e.g., in a normal laboratory environment) at various intervals 

before, during and after the load cell has been subjected to performance tests. The 

performance tests shall include (as a minimum) the temperature test. and, if applicable, the 

damp heat test The damp heat test shall be performed when applicable but may be performed

after a series of span stability tests if the conduct of that test during the span stability test 

imposes an increased risk that the principles expressed under 8.7.3.3. would be 

compromised. This may be a greater concern when conducting tests on higher capacity load 

cells.

The load cell shall be disconnected from the mains power supply, or battery supply where 

fitted, two times for at least 8 hours during the period of test. The number of disconnections 

may be increased if the manufacturer specifies so or at the discretion of the approval 

authority in the absence of any such consideration.

For the conduct of this test, the manufacturer’s operating instructions shall be considered. 

The load cell shall be stabilized at sufficiently constant ambient conditions after switch-on 

for at least 5 hours, but at least 16 hours after any temperature or humidity tests have been 

performed.
November 2015October 2016 OIML R60-21

2-29

Test duration: 

28 days or the period necessary for the performance tests to be carried out, whichever is 

shorter, for temperature and humidity tests.

The duration may be increased to 40 days for CH marked load cells only.

Time between measurements: 

Between 1/2 day (12 hours) and 10 days (240 hours) for SH marked load cells, and 14 days 

for CH marked load cells, with an even distribution of the measurements over the total 

duration of the test. 

Test loads: 

A minimum test load, Dmin; the same test load shall be used throughout the test. 

A maximum test load, Dmax; the same test load shall be used throughout the test. 

Number of measurements: At least 8. 

Test sequence:

Identical test equipment and test loads shall be used throughout the test. 

Stabilize all factors at sufficiently constant ambient conditions. 

Each set of measurements shall consist of the following: 

a) Preload the load cell by applying the maximum test load, Dmax, three times,

returning to the minimum test load, Dmin, after each load application;

b) stabilize the load cell at the minimum test load, Dmin;

c) read the minimum test load output and apply the maximum test load, Dmax. Read 

the maximum test load output at time intervals as near as possible to those specified 

in Table 7 in 8.8.3, and return to the minimum test load, Dmin. Repeat this four 

more times for accuracy class B or two more times for accuracy classes C and D; 

d) determine the span measurement result, which is the difference in output between 

the mean maximum test load outputs and the mean minimum test load outputs. 

Compare subsequent results with the initial span measurement result and determine 

the error. 

Record the following data: 

a) date and time (absolute, not relative);

b) temperature;

c) barometric pressure;

d) relative humidity;

e) test load values;

f) load cell outputs;

g) errors.
OIML R60-2 October 2016

November 2015

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Formatted: Tab stops: 17.78 cm,

Right + Not at 18.89 cm

Apply all necessary corrections resulting from variations in temperature, pressure, etc. 

between the various measurements.

Allow for full recovery of the load cell before any other tests are performed.

Where differences of results indicate a trend of more than half the allowable variation 

specified above, the test shall be continued until the trend comes to rest or reverses itself, or 

until the error exceeds the maximum allowable variation.

8.11 Test sequence 

8.11.1 Test sequence for test temperatures

The recommended test sequence for each test temperature when all tests are carried out in the 

same force-generating system is shown in Figure 35. 

Figure 5

8.11.2 Test sequence for minimum dead load output return 

The recommended test sequence for each test temperature for the minimum dead load output 

return (DR) and creep tests when carried out in a force-generating system different to that used 

for the load tests is shown in Figure 6. 

8.10.2.5 - 8.10.2.8

8.10.3.5 - 8.10.3.10

1 2 3

Temperature 1 hr

stabilized

Load

Time

5 min 30 min

8.10.1.3 8.10.1.5 – 8.10.1.12
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2-31

Figure 6

Recommended test sequence for each test temperature for the minimum dead load output return 

(DR) and creep tests when carried out in a machine different from that used for the load tests.

8.12 OIML certificate 

8.12.1 Preparation of certificate 

The OIML certificate shall be prepared according to the rules contained within the OIML 

Publication OIML Certificate System for Measuring Instruments. The format of the certificate 

shall be as specified in Annex B, OIML Certificate of conformity for load cells. In addition, 

Annex C provides an example of supplemental information that may be included in the OIML 

Certificate and is included in this Recommendation to compliment the format provided in Annex 

B.

8.12.2 Reference of values on certificate 

Regardless of the evaluation result of any load cell in a load cell family, the certificate to be 

issued should not provide for any characteristics or values which are beyond those that the 

manufacturer has requested and for which the manufacturer intends to guarantee, for example, by 

expressing the relevant characteristics and values in its data sheet.

Load

1 hr Temperature

stabilized

30 min

Time

8.10.1.3

8.10.2.5 – 8.10.2.8

8.10.3.5 – 8.10.3.10

OIML R60-1 Bibliography

1

Formatted: Default, Indent: Left: 0

cm