Product Manual

2 Operator’s Manual V03
2. System Description
2.1 Measuring Principle
The test strip is placed on a sliding tray, and a stepping motor moves it under the reading head, which remains stationary.
The ana lyzer reads the reference pad, followed by each of the test pads on the strip.
The reading head contains LEDs that emit light at various wavelengths. Reading is done electro-optically, as follows:
Detector (3) Microprocessor (5)
A/D Converter (4)
LED (1)
Result (6)
Test Pad (2)
The LED (1) emits light of a defined wavelength on to the surface of the test pad (2) at an optimum angle. The light hitting
the test zone is reflected proportional to the color produced on the test pad, and is picked up by the detector, a photo-
transistor (3) positioned directly above the test zone. The phototransistor sends an analogue electrical signal to an A/D
converter (4), which changes it to digital form. The microprocessor (5) then converts this digital reading to a relative
reflectance value by referring it to a calibration standard.
Finally, the system compares the reflectance value with the defined range limits (reflectance values that are programmed
into the analyzer for each parameter) and outputs a semi-quantitative result (6).
Each test pad is read photometrically after about 55–65 seconds. In strongly alkaline urine samples, the Urisys
1100
®
Urine
Analyzer automatically corrects the result of the specific gravity test.