GB/T 42554-2023General requirements for environmental testing of measuring instruments (English PDF)

1 Scope

The document fixes the environmental conditions of the environmental testing of measuring instruments, the technical requirements and test methods of type evaluation, and the test severity levels. It gives the technical requirements and the test methods, at the different test severity levels, for routine performance tests, climatic environmental tests, mechanical performance tests, performance tests of the supply source, electromagnetic environment interference tests and performance tests connected with the supply.

It applies to the environmental testing carried out for the type evaluation and for the routine testing of measuring instruments.

Note 1: the document does not include requirements for instruments unrelated to external influence quantities, for example zeroing devices and totalizers.

Note 2: the document does not deal with the safety of the measuring instrument itself, with electromagnetic emission or with similar tests.

Note 3: the document does not deal with the transport of the measuring instrument while it is not operating.

Note 4: the document does not deal with the remote protocols of the measuring instrument.

2 Normative references

The environmental test methods cited are GB/T 2423.1 (test A: cold), GB/T 2423.2 (test B: dry heat), GB/T 2423.3 (test Cab: steady damp heat), GB/T 2423.4 (test Db: cyclic damp heat, 12 h plus 12 h cycle), GB/T 2423.7 (test Ec: shock caused by rough handling, mainly for equipment-type specimens), GB/T 2423.10 (test Fc: vibration, sinusoidal), GB/T 2423.17 (test Ka: salt mist), GB/T 2423.38 (test R: water test methods and guidance), GB/T 2423.43 (mounting of specimens for vibration, shock and similar dynamic tests) and GB/T 2423.56 (test Fh: broadband random vibration and guidance).

The electromagnetic compatibility documents cited are GB/T 17214.2 (operating conditions of industrial process measurement and control devices, part 2: power), GB/T 17626.1, GB/T 17626.2 (electrostatic discharge immunity), GB/T 17626.3 (radiated radio-frequency electromagnetic field immunity), GB/T 17626.4 (electrical fast transient/burst immunity), GB/T 17626.5 (surge immunity), GB/T 17626.6 (immunity to conducted disturbances induced by radio-frequency fields), GB/T 17626.8 (power frequency magnetic field immunity), GB/T 17626.11 (voltage dips, short interruptions and voltage variations immunity), GB/T 17626.13 (low-frequency immunity to harmonics, interharmonics and mains signalling at alternating current ports), GB/T 17626.17 (ripple immunity at direct current input ports), GB/T 17626.20 (emission and immunity tests in transverse electromagnetic (TEM) waveguides) and GB/T 17626.29 (voltage dips, short interruptions and voltage variations immunity at direct current input ports).

The remaining cited documents are GB/T 17799.1 and GB/T 17799.2 (generic immunity standards for the residential, commercial and light-industrial environment and for the industrial environment), GB/Z 18039.1, GB/T 18039.3 and GB/Z 18039.5 (description and classification of the electromagnetic environment, compatibility levels for low-frequency conducted disturbances and signalling in public low-voltage supply systems, and the electromagnetic environment of such systems), GB/T 21437.2 and GB/T 21437.3 (road vehicles, electrical disturbances from conduction and coupling, parts 2 and 3), GB/T 28046.2 (road vehicles, environmental conditions and testing for electrical and electronic equipment, part 2: electrical loads), JJF 1001-2011 (general terms in metrology and their definitions), IEC 60512-11-8:1995, IEC 61000-4-19:2014 and OIML V1:2013 (international vocabulary of terms in legal metrology).

3.1 Terms and definitions

The terms defined in JJF 1001-2011 and OIML V1:2013 and the terms below apply.

3.1.1 electronic measuring instrument: a measuring instrument that uses electronic means, or is fitted with an electronic device, to measure an electrical or a non-electrical quantity. Any auxiliary device involved in legal metrology is regarded as part of the measuring instrument.

3.1.2 module: a device that performs a specific function or several functions and that can be evaluated separately against the specified metrological and technical performance requirements. A module may be a complete measuring instrument, such as a price-computing scale or an electricity meter, or a part of one, such as a printer or an indicator.

3.1.3 device: an identifiable measuring instrument, or a part of a measuring instrument, or a part of a series of measuring instruments, having a specific function or several functions. A device may be a complete measuring instrument or a part of one; an electronic device may in some sense also be a module.

3.1.4 measurement error: the measured quantity value minus the reference quantity value. The concept can be used in two cases: where a single reference quantity value is involved, as when calibration is made against a measurement standard whose measurement uncertainty can be neglected, or where the conventional quantity value is given, the measurement error then being known; and where the measurand is assumed to be represented by a unique true value, or by a set of true values whose range can be neglected, the measurement error then being unknown. The document notes that measurement error is easily confused with a produced mistake or a lapse of attention. Source: JJF 1001-2011, 5.3.

3.1.5 indication: the quantity value given by a measuring instrument or a measuring system. An indication may be presented visually or audibly, or transmitted to another device; it is commonly given by the position indicated on an analogue output display, by the number displayed or printed by a digital output, by the code pattern of a coded output, or by the assigned value of a material measure. The indication and the corresponding value of the measurand need not be values of the same kind of quantity. Source: JJF 1001-2011, 7.1.

3.1.6 error of indication: the difference between the indication of a measuring instrument and the reference quantity value of the corresponding input quantity. Source: JJF 1001-2011, 7.32.

3.1.7 maximum permissible error: for a given measurement, measuring instrument or measuring system, the extreme value of the measurement error, with respect to a known reference quantity value, permitted by a specification or a regulation. Source: JJF 1001-2011, 7.27.

3.1.8 intrinsic error: the error of a measuring instrument or a measuring system determined under reference conditions. Source: JJF 1001-2011, 7.30.

3.1.9 initial intrinsic error: the intrinsic error of a measuring instrument determined before the performance tests and the durability evaluation.

3.1.10 fault: the difference between the error of indication and the intrinsic error of a measuring instrument. A fault is the result of an unintended change of the data contained in an electronic measuring instrument. A fault is a numerical value, expressed as a measured value or as a relative value, for example as a percentage. Source: OIML V1:2013, 5.12.

3.1.11 fault limit: the maximum value of a fault that is not a significant fault. Source: OIML V1:2013, 5.13.

3.1.12 significant fault: a fault that exceeds the applicable fault limit. The document notes that for particular types of measuring instrument some faults that exceed the fault limit may not be significant faults; such exceptions are to be stated where applicable. For example, one or more of the following faults are acceptable: a) faults arising from causes that occur at the same time and are independent of each other, in the measuring instrument or in its checking equipment; b) faults that could not possibly occur in any measurement; c) transient faults, being momentary changes during indication that cannot be interpreted, stored or transmitted as a measurement result; d) faults that cause a change of the measurement result serious enough to attract attention, the nature of such changes being specifiable where applicable. Source: OIML V1:2013, 5.14.

3.1.13 durability error: the difference between the intrinsic error of a measuring instrument after a period of use and its initial intrinsic error. Source: OIML V1:2013, 5.16.

3.1.14 significant durability error: a durability error that exceeds the value specified in the standard. The document notes that some durability errors exceeding the specified value may still be accepted; such exceptions are to be stated where applicable. For example, one or more of the following are acceptable: a) an error that cannot be interpreted, stored or transmitted as a measurement result; b) an error whose indication shows that no measurement can possibly be carried out; c) an error whose indication is obviously and easily seen to be wrong; d) a durability error that cannot be detected because of the failure of a suitable durability protection facility. Source: OIML V1:2013, 5.17.

3.1.15 influence quantity: a quantity that, in a direct measurement, does not affect the quantity actually measured but does affect the relation between the indication and the measurement result. Source: JJF 1001-2011, 4.8.

3.1.15.1 influence factor: an influence quantity within the range of the rated operating conditions of the measuring instrument. The rated operating conditions are specified by the corresponding standard, and a change of indication caused by an influence factor is regarded as an error and not as a fault. Source: OIML V1:2013, 5.18.

3.1.15.2 disturbance: an influence quantity within a specified limiting range but outside the rated operating conditions of the measuring instrument. The limiting range is specified according to the disturbance phenomena that may occur in the environment in which the instrument is used; a disturbance is usually random in nature; if the range of the rated operating conditions of the measuring instrument does not include a particular influence quantity, that influence quantity is a disturbance. Source: OIML V1:2013, 5.19.

3.1.16 rated operating condition: the operating condition that has to be met during measurement for the measuring instrument or the measuring system to work as designed. The rated operating conditions usually specify the intervals of the values of the measurand and of the influence quantities. Source: JJF 1001-2011, 7.9.

3.1.17 reference operating condition: the requirement specified for the performance evaluation of a measuring instrument or a measuring system, or for the mutual comparison of measurement results. Reference conditions usually specify the ranges of the values of the measurand and of the influence quantities. Source: JJF 1001-2011, 7.11, modified.

3.1.18 durability: the ability of a measuring instrument to keep its performance characteristics after a period of use. Source: OIML V1:2013, 5.15.

3.1.19 checking facility: a functional unit built into the measuring instrument that can detect a fault and produce a response. Detecting a fault and producing a response generally covers an abnormal working state of a part of the measuring instrument, or communication interference between specified pieces of equipment of the measuring instrument. Producing a response means that the measuring instrument gives an adequate response, such as a light signal or a sound signal, or stops the measurement process.

3.1.19.1 automatic checking facility: a checking facility that operates without human intervention.

3.1.19.1.1 permanent automatic checking facility (type P): an automatic checking facility that operates continuously in every measurement cycle.

3.1.19.1.2 intermittent automatic checking facility (type I): an automatic checking facility that operates at certain time intervals, or at a fixed time interval within each of several measurement cycles.

3.1.19.2 non-automatic checking facility (type N): a checking facility that requires human intervention while it operates.

3.1.20 durability protection facility: a functional unit built into the measuring instrument that detects a significant durability error and can produce a response. Producing a response means any suitable response of the measuring instrument, for example a light signal, a sound signal, or the interruption or suspension of the measurement process.

3.1.21 test: a series of operations intended to verify whether the measuring instrument under test (EUT) meets the specified requirements.

3.1.21.1 test procedure: a detailed description of the test operations.

3.1.21.2 test program: a description of a series of tests for certain types of equipment. Source: OIML V1:2013, 5.20.

3.1.21.3 test level: the level of the value of the simulated influence quantity required by a performance test.

3.1.21.4 performance test: a test intended to verify whether the measuring instrument under test (EUT) can perform its intended function. Source: OIML V1:2013, 5.21.

3.1.21.5 durability test: a test intended to verify whether the measuring instrument under test (EUT) can keep its performance characteristics after a period of use. Source: OIML V1:2013, 5.22.

3.1.22 mains power: the main external supply source of the measuring instrument, including all its sub-components, such as a public or local supply network, alternating or direct current, or an external generator.

3.1.23 power converter (power supply device): the voltage sub-assembly that converts the supply voltage into a voltage suitable for other sub-components.

3.1.24 stand-alone battery: a non-rechargeable battery, or a rechargeable battery that can be recharged only when it is not connected to the measuring instrument under test.

3.1.25 auxiliary battery: a battery mounted in or connected to the measuring instrument that can supply power in the same way as the mains supply and can power the whole instrument for a reasonable period.

3.1.26 back-up battery: a battery that can maintain a particular function of the measuring instrument, for example the retention of stored data, when there is no mains supply.

3.1.27 specimen: a representative measuring instrument, piece of equipment or module used for testing, inspection or study.

3.1.28 measurement uncertainty: a non-negative parameter that characterises the dispersion of the quantity values attributed to the measurand, on the basis of the information used. Source: JJF 1001-2011, 5.18.

3.2 Abbreviated terms

The following abbreviated terms apply: ESD, electrostatic discharge; EUT, equipment under test; GSM, global system for mobile communication; MPE, maximum permissible errors; N/A, not available; NSFa, no abnormal fault after interference; NSFd, no abnormal fault during interference.