EuroWire March 2017

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News
Technology
March 2017 56
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.
Zumbach Electronic AG – Switzerland
Website:
Self-calibration of measuring units
▲ ▲ Typical ODAC® laser diameter measuring gauge with reference calibration standards
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: