|
Network
of Excellence
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CARiMan
|
The
Internet Portal for Computer Aided Risk Management
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Responsible:
UBC
Assistance:
TGS, ICS,
FORTH, JenaS, MIRA,
PW,
all
partners
Objectives
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Documentation
/ Analysis upon the adequate types of sensors in connection with monitored
systems and applications included in CARiMan project;
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Documentation
upon European Norms and Standards regarding with technical conditions and
conversion of risk management security and electromagnetic interferences;
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Design
of signal conditioning and conversion model for integrating activities;
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Realization
and experimentation of signal conditioning and conversion model for integrating
activities.
PD
activity is strongly connected with MS, which deals with system monitoring
sensor. Bering for all kind of activities, the sensors rise the same problem:
measuring physical parameters, with analog behaviour, to deliver an electric
signal in a form accepted by other devices, which is converted then into a
digital signal, able to be processed in a computer and presented in a meaningful
form.
Signal
conditioning consists in signals preparing for digitizing. The sensor output,
(usually a voltage or a current) is very small and can be affected of noise,
therefore it has to support some operations like amplification, filtering. Also,
the most types of sensors require excitation (external supplying with voltage or
current), included in signal conditioning module.
Amplification
is necessary to fit the signal to data acquisition system range, to improve the
signal accuracy and to reduce noise. If the amplification is performed at the
data acquisition device, the noise that may have entered in the lead wires is
amplified as well and the original signal denaturises. For this reason, it is
desirable to place the amplification module closest possible of transducer, but
this require miniaturization conditions. The influence of the electromagnetic
fields (i.e. radio waves generated by cellular phones) is well known and must be
taken into account, in connection with European standards. Filtering is
necessary to eliminate unwanted high-frequencies signals, such as the noise from
50 Hz power lines. This operation is performed using a low pass filter; advanced
signal conditioning modules have software-selectable cut-off frequencies. In
addition, sometimes another operations are necessary. Many transducers have a
non-linear response and the measured signal must be linearized.