Brochure

23
A further “on-site quali cation”, also
known as the  rst calibration, is frequent-
ly conducted after the installation of the
system. The requirements of “electronic
records” (21 CFR 11) differentiates bet-
ween the following types of quali cation:
• Design Quali cation (DQ); occurs
during the requirement speci ca-
tion- and technical-speci cation
phase
• Installation Quali cation (IQ);
technical on-site acceptance
such as an inspection of the
wiring on the basis of the
interface diagrams
• Operation Quali cation (OQ);
testing of the measurement chain
from the sensor to the software,
validation of the measurement
chain, testing the accuracy of the
senor
• Performance Quali cation (PQ);
ensures the reliability during the
products “life cycle”
Calibration
Imprecise measurements can have expen-
sive economical repercussions, and for
this reason a periodical adjustment of the
sensors (justi cation), as well as a special
comparison measurement (calibration)
are of the utmost importance. During re-
gular calibration a reference point meas-
urement is compared with a reference
standard, which normally has a much
higher accuracy than the measurement
under test. This round robin test is always
a closed test, because these reference
standards – whether directly or indirectly
– have an accuracy that is based on and
can be traced back to the of cial norm.
In order to calibrate more than one point,
various conditions are generated on site
according to customer requirements e.g.
3 different values for relative humidity.
Such appli cations are indeed qualitative
very sophisticated, and as such require
specially trained personnel with profound
experience in climatologic measurement
technology; especially when dealing with
the setup of comparison measurements
regarding adjustment times.
The following applies to both quali- cation
and calibration: there is a stan-
dard guideline, but no uniform procedure.
Therefore, each user de nes via the IQ/
OQ his special requirements that have to
be observed in both procedures respec-
tively.
Incidentally, Lufft has also been accredi-
ted for air  ow measurement to add to its
existing DKD laboratories for tempera ture,
relative humidity and air pressure.
www.dkd-lab.info
Imprecise measurements can have
expensive repercussions. Therefore,
Lufft products are tested according
to the motto “To trust is good, to
control is better”. Our products have
to pass special tests that exceed
those of conventional ones; fi rstly
through a special type of qualifi ca-
tion, both in production and at the
customer, and secondly with help of
our DKD certifi ed calibration which
ensures incorruptible results.
Qualifi cation
A reliable monitoring system has to ful l
the highest requirements regarding pre-
ciseness and robustness. This is guar-
anteed by a test report that is provided
by the manufacturer with each sensor. In
addition to this, at Lufft the acquisition
and analogue conversion of data is carried
out in a special high resolution (16- or 32
bit technology), so that the preciseness of
the sensors is retained.
A further quality feature is the local dis-
play that visualises measured values with-
out losses due to rounding and with the
same accuracy. At the same time iden-
tical measu rement information is stored
by central software in the archive. These
quality requirements can be additionally
tested during so-called “factory inspec-
tions” or audits of the customer’s produc-
tion plant. Finally, there is an acceptance
test in the plant and the highly sensitive
goods are then sent, sometimes travelling
around half the globe.
Qualifi cation can only be
done by a qualifi ed and
experienced professio-
nals. We ensure that you
have excellent measuring
technology experts at
your side for such a task.