calibration
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Calibration (of MHG. Egos "measure, sight," which in Latin. Aequus "just, equal to" back) is prescribed by law examination of a measuring device for compliance with the underlying custody law, in particular the calibration error limits for the measurement and calibration law . In Germany, the calibration according to the calibration law is a sovereign task.
A calibration mark confirms the expected compliance for the period of validity of the calibration. Calibrations are carried out in the Federal Republic of Germany by the state calibration offices and state-recognized test centers under the technical supervision of the Physikalisch-Technische Bundesanstalt .
calibration
The terms verification and calibration are often confused. A calibration is a sovereign process for measuring equipment in the legally regulated area and achieves a yes / no decision (calibrated, not calibrated). Calibration is the determination of values and uncertainties and is used in scientific and industrial environments.
Calibration law and the public
The calibration law generally serves consumer protection . Measuring devices whose measuring accuracy is in the public interest are subject to legal verification. There is a public interest z. B. for all measurements in the exchange of goods ("business transactions"), but also in the field of occupational safety and environmental protection and in medicine .
Examples are:
- Counter scales, weighbridge, scales to prove compliance with the requirements of the prepackaging ordinance, etc.
- Dispensing measures (e.g. beer glasses, wine carafes, shot glasses) with filling line
- Masses, hollow dimensions , length dimensions
- Petrol pumps at gas stations and other flow meters
- taximeter
- Gas meters , water meters , electricity meters , heat meters
- Radiation dosimeter , tonometer
- Sound level meter
- Clinical thermometer
- Emission measuring devices in use for the legally required examination of the engine management and emission control system
- Speed monitoring devices
Required "normal"
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For calibration are standards required. These are material measures or measuring devices that are adapted to national standards for the measured variable . The calibration office derives working standards from the relevant standard by means of calibration in order to carry out a comparison with the calibration material on site.
Approval for calibration
Only those measuring devices whose design is approved can be calibrated . Therefore, the calibration is an approval procedure at the request of the measuring device manufacturer z. B. at the Physikalisch-Technische Bundesanstalt (PTB) or in Austria at the Federal Office for Metrology and Surveying .
In the case of a type approval , the technical documents are used to check whether the design and properties comply with the applicable calibration regulations. The devices have their accuracy class match and their measurement stability must be guaranteed (d. E. The measurements are during the statutory period within the maximum errors permitted correctly).
Example scales
The calibration capability of a balance is documented by type approval. The scales are first subjected to a calibration test by a calibration office. It includes both metrological and device-specific requirements.
EU-wide validity and international system of units
The type approval is documented by the EC type approval certificate . This type approval is valid in all member states of the European Union (EU).
After successful registration , a will -approval stamp issued, which must be clearly displayed on all instruments of this type. Sometimes it is punched with a punch - e.g. B. on weights for beam balances of trade - or in the form of a seal affixed (see also the main temple ).
The calibration regulations are usually drawn up according to SI units and in cooperation with the metrological state institutes of other countries.
In the EU, the initial calibration of scales and consumption measuring devices (electricity, gas, water, heat) will gradually be carried out by 2015 at the latest by means of a declaration of conformity by the manufacturer in accordance with the Measuring Instruments Directive 2004/22 / EC (MID, Measurement Instrument Directive ) replaced. The calibrations following the manufacturer's declaration of conformity will continue to be carried out at the specified test intervals by the specialist departments of the regionally responsible calibration offices. The measuring device operator is responsible for submitting the application for verification to the competent authority in due time.
Web links
- eichamt.de - Weights and Measures Offices of the Federal Republic of Germany
- metas.ch - Federal Institute for Metrology , Switzerland
- bev.gv.at - Federal Office for Metrology and Surveying , Austria
- LBME NRW - State Office for Measurement and Calibration NRW