WCA March 2017

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Wire & Cable ASIA – March/April 2017
Technologynews
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.
On each of these stages a calibration is
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.
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 ) 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.
All the relevant parameters for accuracy
are continuously monitored by the
measuring system and automatically
compensated when required.
Zumbach Electronic AG – Switzerland
Website:
Self-calibration of measuring units
❍ Typical ODAC ® laser diameter
measuring gauge with reference
calibration standards