AZURA® Detector RID 2.1L / RID 2.1L HighFlow Instructions V6750
4
Product information
The AZURA® Neo electronic platform features:
New microprocessor for faster device performance
Communication interfaces: IP dual stack with switch (for connecting
AZURA® devices among each other) and LAN stack function plus USB
service interface (internal USB to RS-232). Both LAN ports (1 and 2) can
be used as interface or as switch.
Industrial standard 4–20 mA analog input (replacing 0–10 V input on
the previous electronic platform).
No external display support.
1.5
Functional principle
When a ray of light passes from one medium into another the light is
refracted or bent depending on the light ray’s speed of light and the
angle of incidence. The extent to which a medium refracts light is its
refractive index (RI). Snell’s law of refraction expresses the relationship
between the angle of incidence and the angle of refraction.
Snell’s Law of refraction
where
α
1
= angle of incidence
α
2
= angle of refraction
c
1
= speed of light in medi-
um 1
c
2
= speed of light in medi-
um 2
n
1
= refractive index in
medium 1
n
2
= refractive index in
medium 2
n
= relative refractive index
The refractive index of a medium depends on the wavelength of the light
and the density of the medium. Normally, in an RI detector, the wave-
length is constant. The density depends on the temperature, pressure
and composition of the medium.
1.5.1 Detector design and optical path
The AZURA® Detector RID 2.1L HighFlow is a differential refractive index
detector of the deflection type. The detector measures the deflection
of a light beam causes by the difference in refractive index between the
liquids in sample and reference cell compartments of the flow cell.
A light beam emitted from the LED light source
1
crosses the RID’s
sample and the reference cells
2
twice. When both cells contain pure
solvent, the system is calibrated to zero by means of a parallel zero glass
plate
3
which positions the beam on the two detector diodes
4
in such
a manner that the measured light intensities (I
1
and I
2
) of the two diodes
are virtually identical. When the sample cell contains a solution with a
AZURA® Neo
