Roche URISYS 2400, Operator'S Manual, Page: 19 / 166

Roche Diagnostics
Operator’s Manual · Version 1.0 A-3
URISYS 2400 1 Introduction to the system
Description of the URISYS 2400 analyzer
Reflected light is measured electro-optically, and the process is illustrated in
the following figure.
An LED (
A
) transmits light of a defined wavelength, at an optimum angle,
onto the surface of a test pad (
B
). The light hits the surface of the test pad and
is reflected with an intensity that is dependent on the color of the test pad.
A photodiode detector (
C
), positioned directly above the test pad, receives the
reflected light. The photodiode detector transmits an analog electrical signal
to the analog-to-digital converter (
D
), which changes the analog signal to a
digital value.
A microprocessor (
E
) adjusts the digital value, based on a value from an
internal reference plate. It converts the digital value to a relative value by using
a calibration standard scale. Then, the microprocessor calculates a reflectance
value.
The semi-quantitative concentration result (
F
) is determined by comparing
the reflectance value with the so-called range limits (parameter-specific
reflectance values stored in the analyzer). The full list of concentration range
values for all test parameters is shown in:
The results are stored in the memory and can be printed, saved to a diskette,
or sent to another computer.
Each of the three LED’s transmits light of a different wavelength. The use of
different wavelengths improves the results that are obtained from measuring
each of the test strip parameters. The wavelengths used to measure the
different parameters are listed in the table below.
Figure A-1 Process of measuring
A
LED
B
Test pad
C
Photodiode detector
D
Analog-to-digital converter
E
Microprocessor
F
Concentration result
E C D
F
A
B
Optical transmission Electronic transmission
Table F-1 on page F-5