FAQ and Lexicon A-Z

Frequently asked questions & important terms

We provide answers to the most frequently asked questions. Do you have any further questions? Please feel free to contact us.


  • Where can I download the Kessler QMP App?

    Click here to download the app.

  • What is the delivery address?

    Kessler QMP GmbH
    Nisterberger Weg 16
    57520 Friedewald

  • What are your opening hours regarding delivery/collection of our measuring equipment?

    Mondays to Fridays from 06:00 to 16:45.

  • How do I get the calibration certificates?

    Online in the customer area. LOG-IN data can be obtained from the order centre info-friedewald@kessler-qmp.de

  • Do you also offer express calibrations?

    Yes, within 24, 48, 72 hours after coordination via the order centre info-friedewald@kessler-qmp.de or by telephone under +49 2743 933 580.

  • Do you also offer on-site calibrations?

    Yes, vote via the order centre info-friedewald@kessler-qmp.de or call+49 2743 933 580.

  • Do you also offer weekend calibrations?

    Yes, vote via the order centre info-friedewald@kessler-qmp.de or call +49 2743 933 580.

  • Do you also offer new equipment?

    Yes, send enquiry with designation and measuring range by e-mail to info-friedewald@kessler-qmp.de, then the offer for new procurement incl. ISO or accredited calibration will be made.

  • Do you also offer repairs?

    Yes, after consultation and approval of costs.

  • Do you offer torque spanner adjustment?

    Yes, after consultation and approval of costs.

  • Where can I find your accreditation certificate?

    See download area.

  • What is the difference between an ISO calibration and an Accredited Calibration?

    Refer to a PDF for download "Difference between DAkkS accredited DKD and traceable ISO calibration".

  • How long is your accreditation certificate valid?

    The accreditation certificates only show the date of issue. As a rule, the accreditation certificate is valid for an unlimited period of time, until the DAkkS (German Accreditation Body) makes a change.

  • Do you send reminders before the next upcoming due date of the calibration items?

    Yes, on request. 4 weeks before the next due date by e-mail, to the corresponding contact person. The format is freely selectable (Excel, Word, PDF).

Lexicon A-Z

Source: * International Metrology Dictionary, 4th ed. ** Google, Wikipedia

  • Deviation

    Is the exceeding of specified tolerance limits or non-compliance with specified procedural steps. **

  • Display range

    Set of magnitude values delimited by the extreme values of the possible displays. *

  • Accredited calibration

    Accreditation in the sense meant here is, according to ISO/IEC 17011:2018-03, the confirmation by a third body formally stating that a conformity assessment body has the competence to carry out specific conformity assessment tasks. **

  • Out-of-tolerance values

    One or more calibration points have not reached the required tolerance level. **

  • Resolution

    Smallest change in a measurand that causes a noticeable change in the corresponding display. *

  • Reference standard

    The standard with the highest available accuracy from which measurements are derived. Determination and documentation of the deviation of a measuring device compared to another device under given conditions. This device is referred to as the standard. **

  • DAkkS

    The Deutsche Akkreditierungsstelle GmbH (DAkkS) is a private-sector organisation that performs the function of the national accreditation body of the Federal Republic of Germany. Within the meaning of § 1 Para. 4 of the Administrative Procedure Act, the DAkkS is an authority. **

  • DIN EN ISO /IEC 17025

    DIN EN ISO/IEC 17025 specifies general requirements for the competence, impartiality and uniform operation of laboratories. The standard is applicable to all organisations performing laboratory activities, regardless of the number of employees. **

  • DIN EN ISO 9000 / 9001

    This standard specifies the minimum requirements for a quality management system (QM system) that an organisation must meet in order to be able to provide products and services that meet customer expectations and any regulatory requirements. At the same time, the management system should be subject to a continuous improvement process. **

  • Influencing variable

    Quantity that, in a direct measurement, does not affect the quantity being measured, but does affect the relationship between the display and the measurement result. *

  • Sensitivity

    Quotient of the change in the display of a measuring system and the corresponding change in the value of a measurand. *

  • Expanded measurement uncertainty

    Product of a combined standard measurement uncertainty and a factor greater than one. *

  • Accuracy class

    Class of measuring instruments or measuring systems that fulfil specified metrological requirements, by which it is intended that the measurement deviations or instrument measurement uncertainties remain within specified limits under specified operating conditions. *

  • Size value

    Value of a quantity. *

  • Size value scale

    Ordered set of values of quantities of a kind used to order quantities of that kind to decrease or decrease in value. *

  • ILAC

    ILAC is the international organisation for accreditation bodies. **

  • International Size System ISQ

    System of quantities based on the seven basic quantities length, mass, time, electric current, thermodynamic temperature, quantity of matter and luminous intensity. *

  • ISO calibration (factory calibration)

    ISO 9001 is used for ISO calibration. It is a standard calibration in which the measuring instruments are checked for correctness directly or indirectly with the aid of traceable standards (test weights). **

  • Actual value

    Under given conditions, actually occurring value of a [physical] quantity in contrast to the setpoint. **

  • Calibrate

    Calibration in metrology is a measurement process for determining and documenting the deviation of display values of a measuring instrument or a material measure from those of another instrument or another material measure, which in this case are referred to as normal.**

  • Calibration interval

    The calibration interval is the time span between two successive calibrations of a measuring device or standard. **

  • Calibration certificate

    Preparation of a result report, also called calibration certificate, with indication of a complete result, i.e. deviation and calibration uncertainty. **

  • Calibration mark

    The layout of the DAkkS calibration mark corresponds to that of the DAkkS calibration mark on the associated DAkkS calibration certificate. The layout is clearly defined and specified by the Deutsche Akkreditierungsstelle GmbH in terms of shape, size, colour and content. **

  • Unit of measurement

    Real scalar quantity defined and assumed by agreement to which any other quantity of the same kind can be compared in order to express the ratio of the two quantities as a number. *

  • Measurement deviation

    Measured value minus a reference value. *

  • Measuring sensor

    Element of a measurement system on which a phenomenon, body or substance carrying a quantity to be measured acts directly. *

  • Measuring range

    Set of values of quantities of the same kind that can be measured under defined conditions, using a special measuring device or measuring system with a specified device measurement uncertainty. *

  • Measurement result

    Set of magnitude values assigned to a measurand, together with any available relevant information. *

  • Measurement accuracy

    Extent of approximation of a measured value to a true value of a measurand. *

  • Measuring device

    Device used alone or in conjunction with additional equipment to perform measurements. *

  • Measuring chain

    Sequence of elements of a measurement system that forms a single path of the signal from a transducer to an output element. *

  • Measurement

    Process in which one or more magnitude values that can reasonably be assigned to a quantity are experimentally determined. *

  • Measuring method

    General description of the logical procedure for performing a measurement. *

  • Measured value

    Quantity value representing a measurement result. *

  • Uncertainty of measurement

    Non-negative parameter characterising the dispersion of values associated with the measurand based on the information used. *

  • Measurement method

    Phenomenon that serves as the basis of a measurement. *

  • Metrology

    Science of measurement and its application. *

  • Metrological traceability chain

    Sequence of standards and calibrations used to relate a measurement result to a reference. *

  • Nominal value

    Rounded approximate value of a characteristic quantity of a measuring instrument or measuring system indicating its proper use. *

  • Standard or standard measuring device

    Realisation of the definition of a quantity, with specified quantity value and associated measurement uncertainty, used as a reference. **

  • Zero point deviation

    Reference point deviation when the specified measured value is zero.

  • On-site calibration

    On-site calibration (see reference).

  • Federal Physical-Technical Institute (PTB)

    The Physikalisch-Technische Bundesanstalt (PTB) is the national metrology institute of the Federal Republic of Germany and the second largest metrology institute in the world. The PTB is a service provider for science, industry and society and advises the Federal Government on metrology issues. **

  • Testing equipment

    In metrology, test equipment is a technical means for tests[1] that determine whether a test object fulfils a requirement.

  • Inspection equipment monitoring

    Is a component of quality management. It aims to ensure and maintain the quality, reliability, usability and readiness of the test equipment in a company. **

  • Quality assurance

    Ensuring the quality of a product or service through appropriate measures. **

  • Reference value scale

    Size value scale defined by formal agreement. *

  • Traceability

    Property of a measurement result whereby the result can be related to a reference through a documented, unbroken chain of calibrations, each of which contributes to the measurement uncertainty. *

  • SI units

    System of units based on the International System of Units, comprising the names and symbols of units, a set of prefixes with their names and symbols, and rules for their application, adopted by the General Conference on Weights and Measures. **

  • Technical specification

    Technical specifications describe the characteristics required for the service. These may also refer to the specific process or method of producing or delivering the requested service or to a specific process of a life cycle stage of the service. **

  • Validation

    Verification, where the specified requirements are adequate for the intended purpose. *

  • On-site calibration

    Calibration of the test equipment directly at the customer's place of use.

  • True value (reference value or calibration value)

    Quantity value that is in accordance with the definition of a quantity. *

  • Repeatability

    Measurement precision under a set of measurement repeatability conditions. *

  • Numerical value of a quantity

    Number in the expression of a magnitude value that is not a number used as a reference. *


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