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V2018.01 English
Technical background
The philosophy behind NeuLog’s plug and play technology
is based on each sensor’s ability to store its own data due to
an internal flash memory chip and micro-controller in each
plastic NeuLog body. This technology allows the sensor to
collect and then store the digital data in the correct
scientific units (for example: oC, oF, Lux, %, ppm).
The sensor is pre-calibrated at the factory. The built-in
software in the logger can be upgraded for free at any time
using the provided firmware update.
The blood pressure sensor uses the piezoresistive effect.
The transducer is made of two metal foils separated by
silicon; when pressure is applied on the transducer its
resistance changes. One side of it is at complete vacuum
which enables the measurement of the absolute pressure
on its other side.
This transducer is built as a strain gauge with a Wheatstone
bridge circuit. Its voltage's output depends on the absolute
pressure.
When the user pumps, a pressure is applied directly to the
blood pressure monitor cuff’s bladder and it is detected by
an internal sensing unit. The pressure in the cuff is equal to
the pressure operated on the subject's arm.
The heart beats affect the subject's pressure and thus
create very small fluctuations in the gas pressure in the cuff.
This gives an AC signal reading on a DC signal.
The pressure is converted into an electrical signal which
separates into DC (mm Hg) and AC (Arb.) signals. The AC
signal is amplified and added back to the DC signal to
create the mm Hg + Arb. signal.