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4 FUNCTIONAL DESCRIPTION
OSP series infrared portable thermometers block diagram is shown below:
Measuring
ob
j
ect
Emitted IR energy
Optical system
Filter
Detector
Amplifier A/D
converter
Micro-
controller
LCD
display
Tc
Auxiliary
input
Keyboard Digital
interface
Analog
Output
• Optical system
• Filter
• Detector
• Amplifier
• A/D converter
• Microcontroller
• LCD display
• Digital interface
• Keyboard
• Tc auxiliary input (optional)
• Analog output (optional)
The radiated infrared energy is focused by the optical system on an infrared detector sensitive to the required spectral
band. The infrared detector generates a signal proportional to the energy received corresponding to the temperature and
emissivity of the target. See Appendix A for emissivity values.
The output signal of the sensor is then conditioned, converted from analog to digital and transmitted to the
microcontroller. The procedures used to process all the operating functions as well as measure and calculation routines
are stored into the microcontroller memory. Any operator’s instruction, through the trigger and the keyboard is directly
recognized, as a coded signal, by the microcontroller. The actual temperature value and the active operative mode are
indicated on the LCD display.

4.1 Power supply

The instrument is powered, if not otherwise specified with the order, by four internal alkaline batteries or rechargeable Ni-
MH type AA (nominal voltage 1.25 V) that can be recharged through an external charger module supplied as a standard
accessory.

4.2 Keyboard

The operative keyboard is designed with a traditional single microswitch per button for long life and high reliability. The
contact closure of the keys is acknowledged as a coded signal by the microprocessor that recognizes the operator’s
instructions.