2.2 Physical-metrological fundamentals of constructing the RUTS systemsthe RUTS systems
2.2.2 Analysis of the state of the issue and the choice of the direction for
2.2.2.3 Current normative documents for the RUTS systems
In the USSR, previous to 1981 the following basic normative documents regulating general problems of the unit reproduction, transfer of their sizes and construction of corresponding systems were in force.
1) GOST 16263 “National system of measurements. Metrology. Terms and defi- nitions” [195], where the terms related to the problems considered were determined:
astandard, reference measuring instruments, verificationand others. Unfortunately, in this GOST no definitions of the terms “reproduction of a physical quantity” and
“transfer of the unit size” were given.
2) GOST 8.061 “National system of measurements. Verification schemes. Scope and layout” [194], where the classification of verification schemes (national and local) was given and general requirements for the maintenance of verification schemes were formulated. The GOST also indicated the possible methods for verification and metro- logical requirements and requirements for text and graphical representation of verifi- cation schemes in normative documents. It was foreseen that the national verification schemes were “headed” either by a national measurement standard or by measuring instruments borrowed from other verification schemes.
3) GOST 8.057 “National system of measurements. Standards of physical quanti- ties units. Basic provisions” [193], where the ideas of centralized and decentralized reproduction of the unit were given and grounds for centralizing the reproduction of the unit were formulated. Moreover, here the classification of standards (according to their composition and designation) and general requirements for the order of certifica- tion, maintenance and application of standards were presented.
The possibility of the existence of verification setups of the highest accuracy was also provided for. These verification setups were “the head” of the verification schemes when the decentralized method of the unit reproduction was used, and replaced the measurement standards, but for some reason they were legally equated with the status of working standards. In the Supplement to the this GOST, for the first time definitions of terms “reproduction of the unit” and “transfer of the unit” were given.
4) MI 83 “Procedure for determining parameters of verification schemes” [331], which developed the regulations of GOST 8.061 and established methods for deter- mining general parameters of RUTS systems: the relationship between the normalized errors of measurement standard and verified measuring instruments and the estimation of a number of accuracy steps (maximum and minimum). For a more accurate determi- nation of the number of steps it was recommended to take into account the following:
the necessity of a WMS reserve in case of a failure of the basic ones; the availability of the working measuring instruments of limited occurrence for which a deliberately underloaded WMS was created; geographical “atomism” of working measuring in- struments; and special features of the kind of measurements and applied verification means.
The remaining fundamental normative documents (GOST 8.009 [191], 8.010, 8.011, 8.042 and others) concerned only indirectly the problem considered.
All the normative documents on RUTS systems indicated above are based on theo- retical studies and mostly on the works performed at the VNIIM (by Prof. K. P. Shi- rokov [436, 437], K. A. Reznik, and others) before 1973–1975. Unfortunately, they poorly synthesize the large amount of other research.
The experience of applying these normative documents has shown that, together with their undoubtedly organizing effect, very frequently certain difficulties arose con- nected to an insufficient clarity of the regulations they contained and to some self- contradictions. In particular, in the work by M. S. Pedan and M. N. Selivanov [377]
the difficulties connected with an inadequate definition of the status of primary and
Section 2.2 Physical-metrological fundamentals of constructing the RUTS systems 105 special state measurement standards, uncertainty of their composition, and others are shown. Some other defects of the these normative documents are stated above.
Since 1981 instead of GOST GOCT 8.057 and 8.061 a new complex of fundamental documentary standards are in force: GOSTs 8.057 [193], 8.061 [194], 8.372–80, and 8.525–85. In these documents an attempt is made to take into account some defects of previous GOSTs. Specifically, in GOST 8.057–80 the composition of national and secondary standards is stipulated, and in GOST 8.525–85 the problems concerning the legal position of setups of the highest accuracy are considered in detail.
However the new complex has new defects.
(1) Disjunction of two GOSTs into a number of GOSTs, the authors of which are different bodies (groups of specialists), has complicated firstly the work with nor- mative documents (although judging by the amount of data they are equivalent to the two previous GOSTs) and, secondly, has resulted in a number of internal contradictions within this complex. For example, GOST 8.061–80 states that ver- ification schemes have at the head a national measurement standard, while GOST 8.525–85 provides for the possibility of reproducing the unit with a “verification setup of the highest accuracy”.
(2) The status itself and the reasons for VSHA creation remain very dim. In GOST 8.525–85 it is assumed that they are designated to be used either for decentralized reproduction of the unit or for dimensionless quantities and quantities having a
“strictly specialized range or field of use”. At the same time it is not clear what the difference in essence is between a setup of the highest accuracy and a national measurement standard, especially taking into consideration that the transfer of unit sizes from the VSHA has to be realized also in accordance with a national verifi- cation scheme.
(3) Introduction of an additional category of verification schemes into GOST 8.061–
80, which are departmental. At the same time there is an existing category of local verification schemes (which can be of any level of commonness except the national one).
(4) As before the role, place, and general metrological requirements for comparators are not determined.
(5) In GOST 8.057–80 the definitions of terms such as “reproduction of the unit” and
“transfer of the unit size” are not given, i.e., at present they are left without any regulation anywhere.
It should be noted that during a long perior after the development of the fundamental GOSTs 8.057–80 and 8.061–80, a significant number of works on theoretical prob- lems of constructing the RUTS systems (see Section 2.2.2.2) have appeared, but in the new complex of GOSTs the results of these works were practically not taken into ac- count and the ideology of constructing the RUTS systems, as regulated by the GOSTs remained practically unchanged.
The aforesaid, however, testifies not only to the lack of attention by the authors of the GOSTs to theoretical work, but also to the fact that the results of these theoret- ical studies are of little use and are difficult to translate into a simple language for their practical application. In any case the measurement procedure, MI 83–76, has not been revised, although GOST 8.061–80 has established the obligation for quantitative grounds of the optimal decision of national verification schemes.