EuroWire March 2017

News Technology

Self-calibration of measuring units

CALIBRATION in measurement technology means establishing the measurement deviations on the measuring unit. During the calibration no technical intervention occurs at the measuring instrument, as opposed to adjusting where a measuring instrument is set or adapted to keep the measurement errors as small as possible or that the number of measurement errors do not exceed the error limits. The official calibration of a measuring unit is carried out according to the rules and regulations of the examining authority, and the unit is marked with the respective stamp. The examining authority establishes whether the measuring unit fulfils the respective prerequisites. The validity of a calibration period follows practical requirements such as manufacturer’s information, requirements of quality standards or company internal and customer-specific regulations, rather than an official calibration with a fixed time period validity for use. In order to be able to compare results of measurement, it must be possible to ‘feed back’ information via a chain of comparison measurements to a national or international master. For this purpose, the display of the measuring unit in use or the material representation must be compared with the masters in one or more stages.

▲ ▲ Typical ODAC ® laser diameter measuring gauge with reference calibration standards

Standards and regulations, such as the ISO 9000 series, are becoming more important for quality assurance in all industrial nations. Then it may be explicitly required to calibrate all test equipment that directly or indirectly influences the quality of the product. This includes, for example, test equipment that is used as reference during the production process. Zumbach adheres to different standards and guidelines of quality assurance. Zumbach measuring units are calibrated using reference standards which were certified by the Swiss federal office for metrology (www.metas.ch) or by accredited laboratories. Each unit is supplied with a detailed calibration protocol. A regular check for measuring errors along with the corresponding protocol can be carried out according to customer requirements. The regularity of these calibrations is dependent on the customer-specific requirements (internal regulations). The company recommends a check of accuracy every 12 to 24 months. All the measuring heads of the ODAC® series have a self-calibration function (Patent DE3111356) which makes a subsequent, regular calibration superfluous, except when exchanging components. Zumbach Electronic AG – Switzerland Website : www.zumbach.com

carried out with a master which has been previously calibrated with a higher-level master. According to the ranking of the master – of consumption or factory standards via reference masters up to national standards – there is a calibration hierarchy of points to be carried out. Different standards, regulations and guidelines are valid for the expert carrying out of calibrations.

On each of these stages a calibration is

Extension to the range at AFC AFC Cable Systems and sister company Kaf-Tech, both manufacturers of electrical products headquartered in New Bedford, USA, are expanding their line of electrical metallic tubing (EMT), flexible metal (Flex) and Liquidtight fittings for the electrical distribution industry. More than 150 new fittings items have been added. The new product offering is the first phase of a multi-phase fittings product extension, with many more items expected to be added this year. The new products increase the number of applications for which fittings are now available. Many new items have been added to the Liquidtight category, including malleable Liquidtight fittings with aluminium or copper grounding lugs in insulated and uninsulated versions, tubular steel Liquidtight fittings (both uninsulated and insulated), as well as combo couplings to connect Liquidtight conduit to rigid conduit. New AC/MC cable Flex products include 90° saddle type connectors with insulated throats, and double bite saddle type set screw couplings, which are suitable for connecting Flex, AC, MCI, MCI-A and HCF cables to outlets. Also new are combo couplings to connect flexible metal conduit to rigid or IMC conduit. The expanded range of fittings is good news for those already purchasing cable from AFC Cable. Instead of multiple vendors shipping at different times, customers purchasing cable and Liquidtight products can now have access to a wider range of fittings – all shipped from the AFC warehouse so supplies arrive together. AFC Cable Systems – USA Website : www.afcweb.com

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March 2017