CELEX: 51975PC0573
Language: en
Date: 1975-12-17
Title: PROPOSAL FOR A COUNCIL DIRECTIVE on the approximation of the laws of the Member States relating to CHECK-WEIGHING AND GRADING MACHINES (submitted to the Council by the Commission)

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DOCUMENTS "COM"
COM (75) 573
Vol. 1975/0216
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 ---pagebreak--- COMMISSION QF THE EXJKQPEAN CÛMMUNI3ÏES
                                    COM(75)573 final
                                    Brussels , 17 December 1975
                   PROPOSAI. FOR A COUNCIL DIRECTIVE
             on the approximation of the laws of the Member
                            States relating; to
                   CHECK-WEIGHING AND GRADING MACHINES
              ( submitted to the Council by the Commission )
  COM(75 ) 573 final
 ---pagebreak---                                  SIPLAÎTATORY I ® IORAUDUIÎ
•This directive is adopted in application of Article 100 of the Treaty and
 Council Directive N° . 71/31--)/E3C of 2o July 1971 orL "k*1® approximation of the
laws of the Ilember States relating to common provisions for both measuring
 instruments and methods of metrological control ( l ).
The aim is to remove existing technical barriers to intra-Community trade in
the check-weighing and grading machines sector which exist because of diffe­
rences between the national      laws     governing these instruments in the various
Kember States .
The rules applicable in the Member States to check-weighing and grading machi­
nes differ fairly widely .   These differences are not limited to technical
design specifications but also concern the degree of precision required and
the control techniques to which these weighing machines must be subjected before
being put on the market .
At the trading level similar situaticnsarise         from the fact that manufacturers
are obliged to diversify their production to take into account the laws in force
in the Ilember State where the weighing machines are to be used r and the fact
that they have to undergo repeated checks carried out in accordance with diffe­
ring procedures .                                                    '
As the existing national laws are justified by a legitimate wish to protect
consumers and users , the only possible method of removing the inconvenience
resulting from divergences between         the laws would appear to be the harmoni­
zation of those laws and the creation of the conditions necessary for establis­
hing the Common Market .                   1
The term " weighing and grading machines " covers instruments which can        '
- without the help of an operator - divide up a group of articles , also cal­
led " loads", into several subgroups according to the respective weights of
these articles .
There are several types of "weighing and grading machine" ; of these , the
check-weighing and grading machine divides up articles the weights of which
vary on either side of a predetermined value called the nominal weight .
 ( l ) OJ of the European Communities H° , L 202 of 6 September 1971 *
 ---pagebreak---                                        - 2 -
                                       i
■-#acck- weighing machines are used, .chiefly  filling and prepackaging works .
They are used at the end of the process to check whether each prepackaged
lot complies with the appropriate nominal quantity and where it does not ,
to eliminate any lot whose weight or volume falls short of this nominal
value .
This application illustrates how important the instrument is both for the pro­
ducer or packer-."1 and for the end consumer .
To some extent , correct prepackaging of products put on the market depends
on the precision of this type of weighing machine .
This draft directive therefore acts as a complement to Directives on prepac-
kaging submitted earlier and , together with then , forms a corpus which cannot
but be beneficial to the consumer .
In addition , at the same time as bringing about harmonization between the
different national laws concerning theso machines , the directive would make
it possible for them to circulate freely within the Community ; at present
this is not the case .
Defining Community procedures on pattern approval and initial verification for
these weighing machines , and the concomitant reciprocal recognition of controls ,
would simplify the formalities which producers and oustomers have to undergo .
This directive would mean one more measuring instruments sector harmonized at
Community level .
CONSULTAT ION OF PARLLTOTT AND THE ECONOMIC AND SOCIAL COUHTEE
Pursuant to the provisions of the second       paragraph of Article 100 of the
Treaty , these two bodies must be consulted . Implementation of the provisions
of the directive would , in the case of some Ilcmber States , require amendments
to their laws .
 ---pagebreak---                               PROPOSAL J?OR A COUNCIL DIH3CTIVID
                   on the approximation of the laws of^ the Member, States
                      relating to CHECK-WEIGHING AND GRADING MACHINES
                        ( submitted by 'the Commission to the Council )
THE COUNCIL OP THE EUROPEAN COMUNITIES ,
Having regard to the Treaty establishing the European Economic Community ,
and in particular Article 100- thereof ,
Having regard to the proposal from tho Commission ,
Having regard to the Opinion of the European Parliament ,
Having regard to the Opinion of the Economic and Social Committee ,
VJhereas in the various Member States construction and testing methods for
check-ire ighing and grading machines are subject to mandatory provisions
which differ from one Ilember State to the next and therefore hinder trade
in these instruments j whereas it is therefore necessary to align these pro­
visions ,
I'Jhereas the Council Directive of 26July 1971 on the approximation of the laws
of the Member States relating to comra6n provisions for both measuring instru--
ments ana methods of metrological control ( l ) defines the procedures for EEC
pattern approval and ESC initial verification ; whereas-, in accordance with
this Directive , it would be appropriate to draw up technical design and ope­
rating specifications with which these check-weighing and grading machines
have to comply if they are to be imported , marketed and freely used after
undergoing tests and having tho relevant marks and signs affixed ,
Whereas , the abovementioned Directive also states that , where the conditions
allow, the separate directives may specify the date by which each Member State
shall annul the national provisions applicable to instruments similar to those
which comply with the Community provisions f whereas in this case it is not
yet permissible to fix such a date .
HAS ADOPTED THIS DIRECTIVE :
 ( 1 ) 0J of European Communities N° . L 202 of 6 September 1971
 ---pagebreak---                                        Article 1
This Directive shall apply to check-weighing and' grading machines . These
instruments are defined in point 1 of the Annex.                         »
                                     . Article 2
Check-weighing and grading machines for which EEC signs and marks may be
issued are described in the Annex. They shell be subject to EEC pattern appro­
val and EEC initial verification ,               '
                                       Article 3
No Member State may prevent , prohibit or restrict the placing on the market
of entry into service of check-weighing and grading machines bearing the "sign
certifying EEC pattern approval or the mark certifying EEC initial verification
for reasons connected with their metrological characteristics .
                      '            " Article 4                . • ■
                                                                        v
1 . Member States shall- put into force the laws , regulations and administrative
    provisions needed in order to comply with this Direotive within eighteen '
    months of its notification and shall forthwith inform the Commission the­
    reof .              ••             . • '
2 . Member States shall communicate to tha CoouniEsion. the text of the provisions
    of national law which they .-adopt iivthfe fi&ld «ovorod"
    i -> jj. C
                                       Artide 5
This Directive is addressed to the Member States .
                                                                      \
                                                   Done at Erussols ,          v
                                                   For the Council
                                                   The President
 ---pagebreak---                                       r' '          i • ; •'
                                 General    considérations
1 , General definition
    A weighing and grading machine divides up , without the help of an operator ,
    a group of articles , also called " loads ", into several sub-groups according
    to the respective weights of these articles . A distinction is made between*;
    grading and checking machines and grading and classifying machines :
    - a grading and . checking machine divides up articles the weights of which
        vary on either side of a predetermined value called the nominal weight .
        The function of the grading machine is to divide the articles into two
        or more sub-groups according ■ to the value of the difference between their
      ' weight and the nominal weight ;
    - a grading and classifying machine divides articles of different weights
        for which there is no predetermined nominal weight .       The function of the
        grading machine is to classify the articles into several sub-groups , each
        characterized by a fixed weight range .                                      *
        This Directive only concerns checkweighing and grading machines .
2 . Terminolory
2.1 -        Classification of machines
2.1„1 .      according to their , method of operation :
             - weighing and grading      machines with continous movement of the loads ,
               or"coni?inxiQt^ grading   machines " : the movement of the loads oii to
               the load receptor is      continuous and the weight information is
               accfuired during this     movement ;                      . "
             - weighing and grading machines with discontinuous movement of the
               loads , or "discontinuous grading machines" j the movement of the
               loads on to the load receptor is discontinuous and the weight in­
               formation is acquired when the load is at rest .
2.1.2 . '    according to their method of grading :
             The grading may take the form of s
             - the appearance of physically distinct sub-groups leaving the machine j
             - the counting of these sub-groups by meters without any physical sepa«-
               ration :
 ---pagebreak--- – the stamping on each load, of a distinctive mark for the subgroup
   to which it belongs ;
- several of the operations mentioned above .
Component equipment                                                    •;   -
Measuring train '•                          * •                    *
IJeigh cell                                          .       '                   i
Non-automatic weighing instrument or part thereof designed to
supply information relating to the weight of the loads to be gra­
ded.
It consists of a load receptor , a load-balancing device tohich may
be automatic          non««sai<praatic and ^oesibly. ^ ,4. rwijirC    daviQS .,
choitfing-' cit<hcJr^fahe>. srcisD of ths dDnd^t^ight -or ,.*£» diffea,iiacec-l^-:!
mjon rife - .and a irotfxircncc value * in units of weight .
Tripping device                                                        "
Device that gives the order to acquire weight information .
Processing transducer                                                   v     •/.
A device which converts the data from the weighing - unit into an                  "
electrical or other signal and processes this signal to give a
grading order .         '
Grading - indicator                                            ;
A device which gives at least one of the following items of infor­
mation s                          •
- the weight of the- graded load ; j                     ■
- the difference between this weight and a reference value ;
- the sub-group to which the graded load belongs .
                                    "•                                         V *
Load Conveyor
Device designed to enable the loads to be moved on to the load
recepter . It may - form part of the weigh cell .
 ---pagebreak---                                        - 3 -
2,2.3 .     Presetting î)evioe
            Device for fixing the weight limits of the load sub-groups .
2.2.4 .     Grading Device
            Device by which , where appropriate , the loads are divided into phy­
            sically separate sub-groups ..
2.2.5 .     Zeroing Device
            Device which automatically corrects , in the light of the grading
            results , the setting of the machine making -up the loads upstream
            from the grading machine .
2.2.6 .     Counters                .            <
            Devices indicating the number of loads which have moved on to the
            load receptor (movement counter ) or indicating the number of the
            loads in each of the sub-groups ( division counters ),
2,3 »       Grading characteristics
2.3.1 .     Grading Reference Setting
            Value expressed as^a unit of weight , set by the operator by means of
            the presetting device , in order to establish the limit between two
            consecutive load sub-groups .
2.3.2 . •   Grading Point
            Value in unit of weight in respect of which two different grading
            decisions may be taken , each having the same probability .
2.3.3 .   . Grading Range .       _
            Weight interval within which the grading reference settings can be
            adjusted for a given nominal weight - value of the loads .
2.3.4 .     Grading Interval                                       '
            Range , expressed in units of weight between two consecutive grading
            reference settings .          *                      '
 ---pagebreak---                                     - 4 -
2.3 . 5 . Grading Error
          Difference between the value of tho grading reference sotting' and
          that of the grading point .
                                                                    *
2.3 . 6 , Weight Category
          n grading reference settings divide the whole range of weights from
          zero to infinity into (n + l ) weight categories consisting of load
          sub-groups .
2.3.7 .   Drift -
          variation in the value of the grading point per unit of time .
2.3 . 3 . Zone of Indécision
          Extent , expressed in units of weight , of the zone within which the
          machine may make two different decisions in respect of the same
          load .
2.3.9 .   Conventions! Zone.of Indécision
          Zone in which the smallest ratio of distribution of the same load
          in two oonsecutive sub-groups is greater than or ecjual to 0,1
2.3.10.   Grading Rate
          Number of loads graded per unit of time .
2.3.11 .  Load Length
          Size of the load <as measured in the direction in which it is moving.
2.3.12 .  Weighing Time        .              .
          Time elapsed between the moment when the load is completely on the
          load receptor and the moment of acquisition of the weight information .
2.4 .     Metrological characteristics
2.4.1 .   Maximum Capacity (Max )
          The design value of the maximum weight of the load which can be gra­
          ded under normal conditions .
 ---pagebreak---                                                    - 5 -
2,4*2 ,        Nominal Zone of Indécision (u )
               Value of -the zone of indecision , expressed in a unit of weight ,
               which is characteristic of the machine , fixed by the manufacturer
                and shown on the machine . ■
2.4.3 .        Response Time
               Time elapsed between the moment when the load is completely on the
               load receptor ana that following which the instantaneous response
               of the weigh cell differs from the final response by a cjuantity
               constantly less than 0.5U.
2.4.4 .        Scale Division of the Weigh cell                            '               .
               If tho weigh cell has an indicating device , its actual or conven­
               tional scale and its verification scale shall be specified in accor­
               dance with the Annex to Directive N° . 73/36 o/EEC relating to non­
   ,           automatic weighing machines .
3 . Definition of the various machine precision classes
          –i -I  MI » m a –––» io WIKA–■–       MI     >É 'in aimi T-IHII  NEIU * fu *
     The machines are divided into throe classes , according to their maximum
     capacity and their nominal zone of indecision .
     The class is determined by the ratio of the nominal zone of indecision to
     the maximum capacity :                                                         •      , •
                                       Class 0.05 1
                                                       U                     1
                                                      Max        ■^ 1000
                                                        1              ...   u
                                       Class 0.2 : ljJ(X)
                                                      1000                 Max
                                                                           Max     ^ 250
                                                        1             ^ U    υ          1
                                       Class 1         ■ ■■ j -    < -- T
                                                      250          ^ Max1       ■  «C r^r-
                                                                                               « I
 ---pagebreak---                                    CHAPTER II
              PROVISIONS CONCERNING THE OPERATION OP THE MACHINES
4 . Metrological requirements
4.1 .      Minimum Value of a Grading Interval
           This value is equal to twice the value of the nominal zone of inde­
           cision U.
5 , Maximum permissible errors
5.1 ,      On initial Vérification
                             ■ " '            \
5»1«1 «    Weigh oeil
           Wien the weigh cell has its own indicating device it is a non-
           automatic weighing machine for the purposes of Directive N° , 73/360/EEC
           and must fulfil the requirements relating to the maximum permissi­
           ble errors inherent in it. and ascertained through static tests .
5,1,2 ,    Zone of indécision
           The zone of indecision determined during tests carried out in accor­
           dance with this Annex shall not exceed 0,8 times the nominal zona
           of indecision ,
5»1»3 ,    Grading Error
           The grading error shall not exceed 0.8 times the nominal zone of
           indecision.
5,2 ,      In Service
5,2,1 ,    Weigh cell
           When the weigh cell has its own indicating device , it is regarded
           as a non--automatio weighing machine for the purposes of Directive
           N° , 73/36C/te:C and must fulfil the requirements relating to the maxi­
           mum permissible errors inherent in it and ascertained through static
           tests .
 ---pagebreak---                                       - 7 -
5,2,2 , •   Zone of indécision
            The zone of indecision determined during tests carried out in accor­
            dance with this Annex shall not exceed the nominal zone of indecision ,
5«2,3 ,     Grading error
            The grading error shall not exceed the nominal zone of indecision.
6 , Conditions for the application of the maximum permissible errors
6,1 ,       Normal Conditions of Use
6.1.1 .     Weight of loads
            The weight of the graded loads shall be less than or equal to the
            maximum capacity of the machine ,
6.1.2 .     Weighing time
          • This must be greater than or equal to the response time , and less
            than or equal to the time during which the load is completely on the
            load receptor .
            Accordingly , for loads of a given length , there is a maxiraun conveyor
            speed and. a maximum grading rate above which the normal conditions
            of use are no longer fulfilled .
            For all speeds less than or equal to the maximum speed , the errors
            and the gone of indecision shall remain less than or equal to the
            values specified in point 5 *
6,2 ,       Influence Factors
6,2,1 ,     Power supply
            Variations in the voltage of the power supply source ranging from
            + lOfo to - 15 $ of its nominal value and frequency variations of
            + 2 % of the nominal value shall not cause the grading point values
            to vary by more than 0.5 times the nominal zone of indecision.
 ---pagebreak--- Ambient temperature
If the identification plate oarries no particular specification ,
the maohines shall meet the requirements of items      %1,2, and *
5«2,2 , between -10® and 440*0 and the retirements of items
5«1»3 « and 5»2«3» within a range of plus or minus x°C on either
side of any ambient temperature at the time of adjustment , ranging
between 0®C and 30°C#
                                                               i
Machines for which a specific temperattire range of at least 30°G is
given on the identification plate shall meet the abovementioned
requirements only within the limits of this range .
However , when the identification plate specifies that the machine
must be operated in an air-conditioned atmosphere the temperature
range may be reduced to 10°C ,
These provisions apply to stabilized temperatures and to fluctua­
tions in ambient temperature not exceeding 5°C per hour .
Tilting
This relates only to machines which are not permanently fixed to
one plaice . In relation to its reference setting position , a
machine shall meet th : requirements of Point 5 when tilted longi­
tudinally or transversely in a slope of up -to 2 per thousand.
Other factors of influence
The machines shall be proteoted as far as necessary in order to
satisfy the provisions of Section 5 » if» in normal conditions of
use , they are affected by other factors of influence such as
magnetic field , electrostatio force , vibrations , atmospheric con­
ditions , restraints and mechanical stresses .
 ---pagebreak---                        CHAPTER III    '
  PROVISIONS CONCERNING THE CONSTRUCTION OF MACHINES
Suitability for use
Machines shall he so designed that they meet the purpose for which
they are intended and shall he of careful and robust construction.
Reliability
Machines shall be so constructed that a maladjustment or operational
failure cannot normally occur without the effect of the maladjustment
or failure being clearly perceptible .
Oscillation damper
If the effectiveness of the oscillation dampers depends on tempera­
ture thoy shall be fitted with an automatic regulating device . If
this device draws upon a source of power tha using of such power
must be clearly signalled. The damper regulating device must not be
directly accessible to the user .
Convoyor
If the conveyor comprises a belt , tapes or chains intended to pass
the loads on to the load receptor and if the tension of these belts ,
tapes or chains oan affect the weight information received by the
weigh cell it must not be possible for the user diroctly to operate
the device for regulating the tension.
Levelling device level indicator
Machines to which item    . 6,2,3 , applies shall have a levelling
device and a level indicator fastened to the machine in such a way
that they cannot be removed.
Operation of the load-balancer and presetting device
It must be possible to manipulate the control devices both of the
load-balancer and of the presetting device , unladen or laden according
to the type of machine , to within at least a quarter of the nominal
zone of indecision.
 ---pagebreak--- Weight-Indicating devices
Indicating devices graduated in units of weight sliall satisfy the
requirements laid down for weight indicating devices on the non-
automatic weighing machines referred to in Directive N° , J3/360/EEC,
Detachable weights 'and " Balancing weiphts"
The detachable weights used with the check grading machines must "be
in conformity with the SEC Directives N® « Jl/ilJ and N® « 74/148 , their
accuracy class being that appropriate to the class of' the grading
machine.' '
When , from a technical point of view, it is absolutely . neoessary , these
weights may be replaced by "balancing weights " which meet the follo­
wing requirements :                           .
- the shape must be different from that of the detachable "weights ;
- they must bear the following indications » number pf the grading
  maohine and conventional identification of the weight .
Identification
Machines must bear the following data, in the order given t
Data expressed in plain language :
- identification of the manufacturer :
  if applicable , identification of the importer ;
- year and number of manufacture ;
- identification mark -on each component of Machines oomprising separate
  connected components .
Data expressed in oode s
- EEC pattern approval mark {               '
- accuracy class in the following form t
                  for class 0.05 * CL 0,05
                  for class 0.2 t CL 0.2
                  for class 1      * CL 1
 ---pagebreak---         - maximum oapacity , in - the- following' form : Max .....
        - nominal zone of indécision .
          in the following form :                        U » ,«.«,
        - response time , in the following :             't <* •••••
        - where appropriate , accuracy olass and scale interval of the
          weigh cell , in the form provided for in Directive N° , 73/360 EEC }
        - if necessary , an indication of the temperature range , as laid
          down in item    . 6.2,2 ., in the following form : ... °C/.    °G ;
        - voltage and frequency of the electricity supply circuit , in the
          following form s ..... V
                             •• ••• H
7*9*3 * Other data'
        Data other than those laid down in this Annex may be required or
        authorized by EEC pattern approval .
7*9*4 * Appearance of identification data
        Identification data must be indelible and be of such size , shape
        and clarity as to be easily legible .
        They must be arranged on an identification plate fixed in a clearly
        visible manner close to the adjustment controls .
        It must be possible to seal the mounting for the data except if it
        is such that it would be destroyed by removal .                •
 ---pagebreak---                                     CHAPrER IV
                       ^                 .'•          tf    v  ..-.i- ,, ••' ' • .
                              EEC PATTERN APPROVAL
EEC pattern approval of check grading machines shall be carried out in accor­
dance with "the requirements of Council Directive N° . 71/316/EDC of 26 July
1971 on the approximation of the laws of the Member States relating to com­
mon provisions for both measuring instruments and methods of metrological
control, • Certain 6f these requirements are specified in- this Chapter ,
8 , Application for pettéra approvai "                     ' *
      . V 1                            *       »   ■'                    .         .
    The application for E3G pattern approval shall comprise the following infor­
    mation and special documents t                       f
                                             S   » *
8,1 ,       Characteristics               • „,      ,
            - some of the data specified in itsn 7,9 , s
                                                                                     Γ "ί .1 '
            - for continuous grading machines , table showing the maximum opera­
              ting rates in keeping with the conveyor-belt speed and the load
              length ;
            - electrical characteristics of the measuring7 train component *
8,2 , '     Descriptive documents    '
            These shall include schematic diagrams enabling the working of the
            machine to be easily understood , diagrams of el^ctrioal circuits
            relating to supply , pick-up and measurement , and photographs ,
9 , Limited' EEC pattern approval
    Limited EEC pattern approval decisions may be made , after prior consulta­
    tion with the other Member States , in order to permit the performance of
    tests tinder normal conditions of use .
    The validity of these decisions shall bo limited to five years at the
    most and the places of installation of the machines must be notified to the
    competent authorities .
 ---pagebreak---                                        - 13 -
                                                                     s   ~ '■
10, Examination for EEC pattern approval
10.1 ,      Place of testing
            Machines being considered for approval may be installed :
            - either on the premises of the Metrology Service with which the
              application has been lodged j
            - or in any place judged suitable by agreement between the Metrology
              Service concerned and the applicant .
10.2 ,      Provision of the means of checking
            The means of checking which the Metrology- Service may require froci . Jhe
            applicant are the test loads , the means of handling and the qualified
            staff which the performance of the tests demands and the requisite
            checking instruments ,
10.3 ,      Checking that the construction complies with legal requirements
            Machines shall meet the construction requirements specified in Chap­
            ter III .
10.4 ,      EEC pattern approval tests
            Machines which may bear several grading reference settings shall be
            submitted for testing with at least two grading reference settings .
            In the utilization zone the machines shall meet the operating requi­
            rements specified in Chapter II , The operational tests shall take
            into account the conditions for use specific to the machines tested .
10,4,1 ,    Static tests
10,4«1«1 » Tests with eccentric loads
          4
            Under a load equal to one third of the maximum capacity , the extreme
            difference between the values of the standard weights corresponding
            to the equilibrium position when these weights are placed on any
            different points on the load receptor shall not . exceed 0,5 U ,
 ---pagebreak---                                       - 14 -
                                        Î -» î
10.4»1»2 , Special tests for maohines the weigh cell of which is a self-
           oontained non-automatic weighing machine
                                              ,τ, ^ .·   ι..  ... ψ , .   .··. <·_,·· ·· - ./ ...   ,» Α   . ·... * ·· . *
           The non-automatic weighing machine shall undergo the . sensitivity ,.
           motility and accuracy tests specified in Directive" N° . 73 /360/EEC
           of 19 November 1973 »                       ,     ■-         <                         •           \
           The permissible reading errors shall be , the same as those for non-
           automatic weighing machines in keeping with their scale division and
           accuracy class .
10.4.1.3# Variation of the grading point under the effect of influence factors
           The purpose of these tests is . to determine statically the variation
           of the grading points for different loads not greater than the maxi­
           mum oapacity . under the effect of the various .influence factors
           listed in item      6.2 .
           The variations obtained under the effect of each influence factor
           must be compatible with the provisions of item                                      6.2 ,
10.4«2 . ' Measurement of' Response time'                    1 ■- --            •      •                 •
           The response time shall be measured under conditions frae of influence
           factors . The values obtained must be less than or equal to the value
           shown on the identification plate .                        , .
           The data referred to in item , 8.1 . concerning the maximum operating
           rates as a function of the belt speed and the load length must be
      '    compatible with the values obtained for the response time .
10,4.3 . : Tests under normal conditions of use
10.4«3«1 « Zone of indecision and grading error                                                                            ♦
           The tests , under normal conditions of use , shall be carried out in t
           accordance with the method described in item                                    12.3«1 » (Reference
 '' ■      method) j with the machine operating either on a production line or on
           a load circuit simulating a production line , the test loads , of
           various weights - above and below a mean value , being themselves quite
           numerous .  - . .            -   .     .
 ---pagebreak---                                        - 15 -
10.4«3»2 . Drift of the grading poirit
           These tests', carried, out with loads of the same nominal weight without
           altering the machine settings and without varying the factors of
           influence , shall be repeated several times during a period of at least
           eight hours *  The grading errors must conform to the provisions of
           item 5,lo3»     without the difference between the extreme values
           exceeding 0.5                               i ■     -
10.5 ,     BEG pattern approval test report
           The EEC pattern approval test report shall include the results of the
           tests specified in item      10.4# and any relevant data arising from
           the various tests , especially from those on the operating safety de­
           vices .
           In its conclusion, the report shall oontain an opinion for or against
           EEC pattern approval .
10,6 .     Special conditions required by EEC pattern approvai
           When EEC pattern approval requires the machines to oomply with special
           conditions , these must be shown on the pattern approval certificate .
 ---pagebreak---                                       - 16 -
                                    CHAPTER V
                             EEC INITIAL VERIFICATION
EEC initial verification of weighing and grading machines shall be carried
out in accordance with the requirements of Council Directive N e . 7-/316/EEC
of 26 July 1971 on the approximation of the laws of the Member States rela­
ting to common provisions for both measuring instruments and methods of metro­
logical control .
These requirements shall be supplemented and rendered specific by the follo­
wing special provisions t
11 . Place of EEC initial vérification
     EEC initial verification shall be carried out in two stages :
     First stage - at the choice of the Metrology Service concerned }
       at the verification office or
       on the premises of the manufacturer or his agent or at the place of
       installation .
     The second stage shall be accomplished at the place of installation by
     the competent local Metrology Service .
12 . Methods of testing
12.1 .     Provision of means of testing
           The material means which the metrology service may demand from the
           applicant are , in particular : the test loads , the handling equip­
           ment and qualified staff required to perform the tests , and the
           requisite testing instruments ,
12,2 ,     Tests during the first stage
           These tests are the static tests specified in    item   10.4«1 *
12.3 •     Tests during the second stage
           These tests may be carried out either by one of the methods hereinaf­
           ter described or by any other method offering equivalent security .
 ---pagebreak---                                        - 17 -
           Reference method (sea item ^ 14.2 .)               V . . V       ■*' •
           In respect of the nominal set point the machine shall be caused
           to check test weights at 7 points spanning the zone of indecision.
           Assuming that the approximate values of the set point and of the zone
           of indecision are already known or are determioed "by means of preli­
           minary tests , the mass of the test weights to be used is obtained as
           follows i
               y =» A + I0645 .g-  g 3 A + 1,282      ^ A + 0.84-2 m^ » A
           where t
           A «             B - H - L
           H and L are the approximate values of the mass at the limits of the
           zone of indecision.
           The test weights shall be similar in shape to the articles which the
           machine is designed to cheokweigh.
           Each test weight shall be passed over the machine 50 times , except
           in the case of the two ( 2 ) lightest and two heaviest weights ,
           which shall be passed 200 times each®
           The test weights shall be passed in random order*      However , the test
 -y        weights at the opposite extremes of the zone of indecision should fol­
           low each other consecutively , separated by a time interval which cor­
           responds to the maximum rate of checkweighing.
           The results logged for the various tests shall be set out in a table
           as showtt under item 14»2 , From these results it will be possible
           to calculate the zone of indecision and the set point in the pres­
         . cribed manner.
12,3,2 ,   Method A
           A load is employed the weight of which is equal to the minimum desi­
           red load,                                        '
           Adjust the "minimum" operating reference setting so that a "minimum
           signal always appears during "n" weighings .
           Make certain that         when the load in increased by a value approximate­
           ly one tenth of the nominal zone of indecision the "normal" signal
           appears at least once during "n" weighings .
           Continue the test by increasing the test load by low values until the
           " normal" signal is obtained constantly in the course of " n" weighings .
           The difference between the t wo extreme values found is an estimate of
           the zone of indecision , the difference between the grading reference
           setting and the middle of this zone being the estimate of the grading
           error.
 ---pagebreak---                                         - 18 -
12.3,3 .      Method B ( seeitem    14.3 .)
              If the machine has at least two grading reference settings both
              must be adjusted until -a load distribution in the three weight cate­
              gories is obtained , the grading interval being approximately 1,5 .
              to 3 times the nominal zone of indecision.
V .      •       •
              Once the machine is working normally , separate from the other loads
              the first 200 loads classed in the abovement ioned grading interval ,
              weigh them on a suitable checking instrument , eliminate the two
            ; extreme values found and note the penultimate values .
              The discrepancy between the difference between the penultimate values
              and the grading interval is an estimate of the zone of indecision }
              half the sum of the penultimate values minus half the sum of the
              grading reference settings is th e estimate of the grading error.
              If the machine has only one grading reference setting , adjust it so as
              to obtain a virtually equal distribution between the two categories .
              Weigh the first 200 loads of eaoh category , noting the penultimate
              values , the heaviest of the light category and the lightest of the
              heavy category } the difference between these two values is the
              estimate of the zone of indecision , the estimated grading point being
              equal to half the sum of these two values .
12,3.4»       Method C (sce item 14,4o )
           . This is derived from method A and requires calculation , but it presup­
              poses that the distributions around a grading point obey the normal
              law, .
              Adjust the test load to a value x^ such that a "minimum" signal
              appears almost constantly and the "normal" signal appears only k^
              times ,    being very small compared with the number "N" of times this
              load passes among the others of the batch to be ohecked.
                                                                   „        * «  •
              The test load shall then be adjusted to a value x^ such that kg ^ the
              number of times when the " normal " signal appears , approximates very
              closely to "N", the number of times the load passes .
 ---pagebreak---                          - 19 -
As the ratios       and      are respectively equal to P.% and
                 N       N
P^f the tables of the normal law make the reduced normal variables
u^ and u2 correspond, to     and P2# •            ■*
Now u a –     ■ and knowledge of the values x^,       ^      u2 Sivss
the values for m (grading point ) and<j-( standard deviation o'f the
zone of indecision)^ Where N =» 100£?"and m can he satisfactorily
determined.
                                                       \
 ---pagebreak---                                      - 20 -
                                   CHAPTER VI
                            IN-SERVICE  VERIFICATION
13 ». In-Service tests
      In-service checks shall "be made under the Same conditions as the second-
      stage tests of the initial verification and carried out under normal con­
      ditions of use , the maximum permissible errors provided for in item
      5«2» "being applied.
 ---pagebreak---                                       - 21 -
                                    CHAPTER VTI
                                S
         ZONE OF INÏÏECISrj
             the loads are distributed in a random fashion around a grading
        point , experience shows that the zone of indecision does not have
        precise bounderies and it is thus necessary to take as a value for
        this zone the difference between the two loads , the smallest ratio of
        distribution of which in each of the sub-groups is lower than a de­
        termined percentage which is the same for each of the loads.
        Therefore the zone of indecision could be defined as follows t
        The zone of indecision is the zone in which the smallest ratio of
        distribution of a given load J.a two consecutive sub-groups is grea­
        ter than or equal to –-
                                  2
14. 2 , RETTÎH3NCE METHOD
        Procedure in logging the test results and calculating the zone of
        ih&é£Î£ion^and^the set point .
        IIο is the mass of the test weight to which incremental masses xι. are
        added. If a particular test mass ( Mq + x^) is passed over the machine
        n i. times and is aocepted r i. times ,' then r.î'/n i. will vary from 0 to 1
        as i varies from 1 to k,      k is thus the number of different test mas­
        ses which are used to span the zone of indecision ( ie from i a
        2 to i a k-1 , 0<^z\ /n^ <^l).
        The test result values of         r^ and n^ are entered into the table below0
        The values for nw and nwy are found from tables 2 and 3 for n a 50 and
        n a 200 respectively.
                                        2
        The values of n.w.x .
                         ill , n.w.x
                                  ill. and n.w.x.y
                                                 iii^i. are then calculated and
        columns 5 » 6f 7i 8 and 9 are summed to give respectively
        \ n.w . , \ n.w.y . t \ n.w.x ., N n.w.x .         ^ n.w.x.y .,
        /_ I i 1 / i 11 x* l i i * / i_a. i                / i l iJ i *
          i=l       i=l
 ---pagebreak---                                                       - 22 -
                                                   ТАЧГ.Д
                                                   «манаймим
                                                                 1
                 Col . 3 Col . 4         Col . 5      Col . 6             Col . 7            Col . 8        Col . 9
 Col . 1 Col . 2
                                                                                                       !
                                                                                                   2
                  Γ        i               nw           nwy                 nwx               nwx            nwxy
   X         n
                           1                       Wi
 h                  1
                                         η
                                                                         Υπ                 nlwl 1        ViVi
                                 ι                                   i                   i
          I                                              •           i                 • i
                                                                                                                ♦
   *
                                                                                                     2
             n.   r.       i             n.w .     n.w.y .               n.w.x .            n.w.x .: .     n.w.x . y .
 X.                                        i i        îix                 îii                i i 1           1111
  1            i    x
                                                                              •           i
                                                                                          I
                                             ♦
                          k                        Wk                    Wk
 *k               rk                     Vk                                                 Wk             YkVk
                                                              \
                                  I              1
           i                                     i
           i
                                                      k                   k
                                         k
                                                                                             k       2     k
                                                   &Vi                  Ση_ι. ν/.ιχ ι.      av i         \ n . w.x.y
                                                                                                         vi     i iJ i.
                                                    »
                                         1            1                   1                    i           1
                                  I
The following quantities are calculated, from the summations given in Table 1."
                                     n.w.x .
                                     . 111
                         X     V 1 ■ n.w .
                                >_ ii
                                     n.w.y
                                     . 1 l"7 !.
                         y      «v   n.w .
                               ^– i        i
                                                                (\–n.x.x
                                                                       i i i'
                                                                             .) .
       S(nwxx )                      n.w.x .
                                     • iii                         n.w .
                                                                   . l i
                                                                (\ n.w.x . )
                                                                 -–i li 7
       S (nwxy )               Vn . w.x.y .
                               2       i iii
                                                                              n.w .
                                                                             –i i
       and                           S ( nwxy )
                                     Slnwxxl
 ---pagebreak---                                                     - 23 -
Then the estimate M of the set point M is given "by
                        A           A       A       ^        1 –
                        M « M    + m wherem » x          - r y
                               o                             D
The estimate V (m ) of the variance of ft is given "by
                                                                       - 2
                        V (m) = lЪ2       <r– n.w . .
                                                                       У
                                          2      i i           b S(nwxx )
The estimate Z of the zone of indecision Z is given "by
                      . z2 -= -2-
                              -r       •
                   ^ 4%                              A
The estimate ?(?) of the variance of Z is given by
                                         36
                        V (Z ) =
                                     b S(nvooc )
 The interval of oonfidenoe at 100 (l                        – ) $ whioh straddles the true value
 of the characteristic , in other words tSI interval for whioh the probability'
 that it straddJ <=■« the true value is at least (l                          – ) , is obtained by applying
                                                                           C2
 Tchebyoheff *s inequality which states that
                          I',      ■ ■       : ,  ■  *          V )   • 1 -
          » I •< <
                                                                               7.2
 Where C is chosen to give the required minimum probability
       E is the estimate of the value of the characteristic obtained from the . ,
            test data                                     '
       T is the true value of the characteristic
       V is the variance of the estimate E obtained from the test data
 Using this formula the limits to a double-sided 95 % oonfidenoe interval on the
 set point M are *»
                                  M -\/20 V(m)and M +V20 V (m)
 and the limits to a d®uble-sided 93 $ confidence interval on the zone of indeoision
 Z are ,*                  -                              >.        .
                                  * \ !     A A        /     A   \ /      A .A
                                  Z -y 20 V (2 )and . Z +V 20 V (z )    i                                  '
 The values for nw. and nwy are showon in tables 2 and 3 for n - 30                              n ■ 200
 respect iv ■' /"v
 ---pagebreak---                                         TABLE 2     n a 50                                    - 24 -
                                r   1             ■
                 I '    nw      |           r>vnr                Γ                nvr             т-лг
                                 f
   H-t–f              3.588           -   8.346                ' 3.5           28.73/           15.094
   I    n
                      5.081           - 12.28 ?                  36            28.10/!     ;    16.380
        ?             9.669           - 16.928                   37    i
                                                                       i
                                                                               27.3/12  ♦;      17.591
                     12.580           - 19.559                   38            26.492      !I   18.711
                     15.015           - 21.097                   39    !       25.546      !    19.726
                     17.111           - 21.929                   40            2Д. / 9Л         20.614
        6            18.947           - 22.263                   41    I       23.325     I     21.351
                     20.574           - 22.226                   42             22.02/1    !    21.902
        7
        8            22.024           - 21.902        i          43            20.574           22.226
                     23.325           - 21.351        j          44             18.947    |     22.263
        9
                     24.494  i        - 20.614                   45             17.111          21.929
       10 .
  I 11        !      25.546           - 19.726                   46             15.015          21.097
       12 /:         26.492           - 18.711                   47             12.580          19.559
       13            27.342           - 17.591                   48              9.669          16.928
                     28.104           - 16.380                   49              5.981          12.282
       14
                                                                     *
                     28.784           - 15.094                   50              3.588           8.346
       15
       16            29.386           - 13.744
       17            29.915           - 12.339
       18      !     30.374    i      - 10.888                               f
                               ι
       19      !     30.767        . - 9.399
       20            31.096           -   7.878
       21            31.363           -   6.332
       22            31.569           –   4,766
     . 23            31.715           -   3.185
                                                                         I
       24            31.802           -   1.595
                     31.831                0                 «
       25
       26            31.802               1.595
       27.'          31.715               3.185
                                                                         !
       28            31.569               4.766                          !     •
                                                        i. •
       29            31.363               6.332      4i
                                                        i
                                                        i
       30            31.096               7.878         I
                                                                         i -             -i
       31            30.767               9.399
       32            30.374 |            10.888
                                                                                          i
                                                                                           I
                                                                                           i
       33            29.915              12.339
                                                                                          i
  l 34       j       29.386              13.744
The values of nw, and nwy in this line shoild only be used for the highest value
of x when r =» o or the lowest value of x wl«n r « 50.
 ---pagebreak---                                                  TABLE 3         n » 200                                             - 25
                                   1           ~       –
                            nw
                                    }            nwy           I
                                                               I
                                                                         r        I       ' nw                    nwy
         0               4.831                - 13.56O                  40        |         97.974      Γ . - 82.456
          1              8.406               - 21.650                   41                  99.086            - 81,620
         2
         3
                        14.350               - 33.384                   42                 100.132       * - 80.750 J
                        19.414               - 42.128                  43                  101.170            - 79.842 ; J
         4              23.922               - 49.128                  M                   102.182            - 78.904
         5              28,028               - 54,932                  45                 103.166             - 77.932
         6             31.820                ~ 59.846                  46                 104.124             - 76.932
         7             35.356                - 64,052              ' 47                   105.058             - 75.902
!       8         .    38.676                - 67.710                  48                 105.968             - 74.844
        9              41.812                - 70.890                  49                 106.852            - 73*762
       10              44*788            . » 73® 668                   50                 107.714            - 72.652
       11              47.618               » 76.102                   51                 108.552            - 71.518
       12              50.320               - 78.236                   5?                 109.368            - 70*362
      13               52.906              - 80.104                    53                110.162             - 69,182
      14              55.386               - 81.736                   54                 110,936             - 67.982
      15              57.768-         .    - 83.158                   55        I        111 . 686           - 66.762
      16              60„0S8               - 84.386                   56                 112.416             - 65.520
      1?              62.268               - 85.444                   57                 113.126             ~ 64.262
      18              64.398   ;           - 86c 342                  58                 113.814            - 62.984
                               ι
  ■" 19       .       66.454              - 87.094     -
                                                        . ii
                                                                      59                 114.484            - 61.688
     20              6S,âAÛ      !        - 87.714                    60                115.134             - 60.376
     21              70.368      !        - 88,212                   61                 115.764     ;       - 59.048
                                 i         '
     22              72,232               - 88.594           !     . 62     |           116.376             - 57.704
    23               74.038               - 88.872           i       63                 116.968    !i       - 56.346
    24      •        75.788               - 89.050                   64                 117 . 542           - 54.974
    25               77.486               - 80,138                   65                 118.0Q8             - 53.563
    26              79.136               - 89.138                    66       I         118.636       I     - 52.190
    27              80.733               - 89,058                   67                 119.156        ! - 50.778
    28
                    82 . 294             - 88*902                   68                 119.658             - 49.354
   29           . 83.806                 - 88.676                   69                 120.1 44            - 47.920
   30               « 5*276              - 88.382                  70                  120.612             - 46.474
   31              86.706                - 88.024                  71                  121.062             - 45.018
   32             88.096 .               - 87.608                  72                  121.496             - 43.^2
   33            89 . /ISO              - 87.134                   73                  121.914            - 42.076
  34             90.766                 – 86 . 606                 74               , 122.316             - 40.590
  35             92.050                 - 86.028         j        75                  122.700             - 39.098
  36             93.298
                                                         i
                                        - 85.402                  76                  123.068             - 37.596
                                                                          1
  37             94.514                 - 84.728                  77' }               123.422             - 36.086
  3S v           95.693                 - 84.012                  78                  123.758            - 34.568
39              96.850                  - 83.254                  79                  124 . 07Ô           - 33.044
 ---pagebreak---                                   TABLE 3         ( oontd.) n - 200               - 26
       I          nw               nwy                   Γ            nw        nvnr
 80             12/1.384       - 31.512               120           124.384   31.512
 81             124 . 674      - 29.974               121           124.073    33.044
 82             124.948        - 28.432               122           123.758    34.568
                125.206        - 26.882               123           123.422    36.086
 83
 84             125.450        - 25.328               124           123.068    37.596
 85             125.678        - 23.768               125           122.700    39.098
 86             125.892        - 22.040               126           122.316   40.590 .
 87             126.090        - 20.636                127          121.914   42.076
 88             126.274        - 19.064                128        . 121.496   43.552
 89           ' 126.442             17.488          , 129           121.062   45.018
 90             126.596         - 15.908              130           120.6T2   46.474
 91             126.734        - 14.326               131           120.144   47.920
 92  !          126.858        - 12.740               132           119.658   49.354
 93             126.968        - 11.154               133       •   119.156   50.778
 94             127.062        -     9.564            134           118.636   52.190
 95             127.142        -     7.972    !       135           118.098   53.588
 96        .    127.208        - 6.380        |       136           117.542   54.974
 97             127.258        - 4.786                137           116.968   56.346
 98             127.294     !L - 3 . 192              138           116.376   57.704
 99             127.316        -     1.596            139           115.764   59.048
100             127.324                 0             140           115.135   60.376
101             127.316        ..    1.596            141     ;     114.484   61.688
102             127.294              3.192            142     i     113.814   62.984
103             127.258              4.786      "     143           113.126   64.262
104             127.208              6.380            144           112.416   65.520
105             127.142              7.972 .          145           111.686   66.762
106             127.062              9.564            146           110.936   67.982
107             126.963            11.154             147           110.162   69.182
108             126.858              12.7*0           1 /18         109.368   70.382
109      . .    126.734              14.326           149           108.552   71.518
110          . 126.596               15.908           150           107.714   72.652
111             126.442              17.488           151           106.852   73.762
112             126.274 - '          19.064           152           105.968 i 74.844
113             126.090              20.636           153           105.058   75.902
114             125.892              22.040         . 154           104.124   76.932
115             12S , 678            23 . 768         1*5           103.166   77.932
116    !        125.450              25.328           156   \       102.182   78.904
117    !        125.206              26.882           157           101.170   79.842
118             124.948              28.432           158           100.132   80.750
119 |           124.674              29.974           159            99.086   81.620
 ---pagebreak---                                                        TABLE 3 ( contd ) n « 200                      - 27
      г                    nw
                                     j_„
                                        jrivy i   :  i
  Γ 160                9~ , 974         } 82T456 1
     1*1               QA.8^0               8 3.254
     162               95.698               8/1.012       ¥ The values of nw and nwy in this line Bhould
                                                            only be used for the highest value of 1 .
     163               9/1.514              84.728          when r ■ 0 or the lowest value of x when r =•"
     1M                93.298               8^.402
 ! 1^5
 *
                       92 . 050             86.028
     1бб               90,766               86 . 606
     167               89.450               8 ?» 134
     168               88,095          i    87.603
    169          j     86,706               88.024
    170                8^.276               88.382
    171                83.806               88.676
    172                82.294               88.902
    173                80.738               89.058
    174                79*136               89.138
    175                77.486               89,138
    176    ■;          75.788               89.050
i 177 . I              74 «. 038           88.872
    178      ii        72.232      ;       88.594
    179      i         70.368      i       88.212
    180  •     !   " , 6'8.44<3 ■ !        87.714
    181     I          66,454              87.094
    182     Ij         64,393              86,342
    183        ï       62.268        î     8S.444
    184             • 6O.O58         '     84.386
    185                57.768              33.158
    186                55.386              81.736
    187                52.906              80 , 104
    188                50.320              73.236
   189                47.618             - 76.102
   190                44.788               73.668
   191                41.812               70.890
   192                38.676     .         67.710
   193                35.356               64.062
   194                31.820               59.846
   195                28.028               54.932
   196                23.922               49.128
   197                19.414               42.128
   •198               14.350               33-384
   199                  8.^06              21.560
   200*                 4*831              13.560
 ---pagebreak---                                    - 28 -
  14,3 , НЙГНОО В
         Let it be assumed, therefore , that a percentage q^ of loads outside
         the limits of the zone of indeoision which it is desired to determine
         can be placed within this zone , and let (l -0*^) be the probability
ч
         that this hypothesis can be accepted without there being a probabi­
         lity jQ that a certain percentage q^ (q^        q^) wiUl be exceeded.
         From these values (O^j q^ -         * qg) it is possible to determine
         the size n of the sample to be achieved and the acceptable number^ o
         of loads which may be eliminated in order to determine the value
         of the zone of indecision.
                                                                c
         n and o having been fixed , the mean percentage q = –    is determined
         with a oonfidence interval equal to 1 -               )» It should be
         observed that , sis c and n must be whole numbers , those which are
         calculated are to be considered as approximate values .
         Assuming that the percentage of the loads abnormally placed in the
         zone of indecision is q^, elimination of "c" extreme loads , corres­
         ponding to the mean percentage            only leads to a result with
         negative deviation , i„e „ at the most equal to the true value of the
         aone of indecision and therefore to the nominal zone of indecision
         with which it is desired to compare it #
         Moreover , as the grading point is defined as the value of the loads
         likely to be placed , with a probability 0f 0a 5 , in cne or other of
         the sub-groups which it separates , the half sum of the extreme values
         selected constitutes an estimate which will be proportionately better
         where the grading reference setting or setting are closer to the
         mean value of the population to be graded and the size of the sample
         is larger .
         If one selects , q^ s» 0.002 and     » 0,05 in respect of n = 200 and o =
         2 the zone of indeoision is determined with a oonfidence interval
         practically equal to 0#99 ( seQ table 4 )»
         It should be observed that this method appears to be more particular­
         ly applicable when the initial and periodical verifications are car­
         ried out , i.e , when it is a question of ensuring that the nominal zone
         of indecision is not smaller than the experimental zone of indecision ,
         the value of which is only a result with negative deviation#
 ---pagebreak---              ч
                                    TABLE 4   n » 200                              - 29 -
         0,001     0.002    0.005     0.0083      0.01    0.0133     0.02     0.05
 c    \
        0.9825     0,9386   0.7358      0,5    0.4044              0,0908   0,0004
        0,9988     0,9921   0,9202             0,6766         0,5  0,2357   0,0023
Probability of finding in a sample of size "n" a number at most equal to noN defective
loads where the percentage of defective loads in the batoh is "qw .
14.4 .    METHOD C
          This method appears to be better suited for determining the zone of indeci­
          sion since it produoes the standard deviation of the distribution.
          What is more , it may be aooepted where N is large , that the experimental
          standard deviation n sH approximately obeys a normal law with mean (P^~
                                         CT"
          and standard deviation          ■     t which -    • when a speoifio confidence
                                   V     2B
          interval is adopted enables the uncertainty of the measurement to be found.
          This , in the oase of a confidence interval approximating to 0,99 the
                                            β
          limits of (y' are s + 2.5 –7 '             # roughly therefore , where N ■ 100 ,
                                        V      r»
          The position of the grading point is determined , in the oase of the same
          confidence interval , with a similar uncertainty.