Fluke Ti20 User Manual page 52

Ti20
Users Manual
Blackbody
A perfect emitter; an object that absorbs all the radiant energy incident on it at all
wavelengths and reflects and transmits none. A surface with emissivity of unity (1.00).
Calibration
A methodical measurement procedure to determine all the parameters significantly
affecting an instrument's performance.
Calibration Source
A source (blackbody, hot plate, etc.) of known and traceable temperature and emissivity.
Usually NIST traceable in the USA, with other recognized standards available for
international customers.
Colored Body
See Non-Gray Body.
D:S
Distance to spot size ratio. See Optical Resolution.
Detector
A transducer which produces a voltage or current proportional to the IR energy incident
upon it. See also thermopile, pyroelectric, and Si detectors.
DIN
Deutsches Institut für Normung (DIN) is the German standard for many instrumentation
products.
Display Resolution
The level of precision to which a temperature value can be displayed, usually expressed
in degrees or tenths of degrees.
Drift
The change in instrument indication over a long period of time, not caused by external
influences on the device (per the ASTM standard test method E 1256-88).
EMC
Electro-Magnetic Compatibility is the resistance to electrical signal disturbances within
IR thermometers.
Emissivity
Emissivity is the ratio of infrared energy radiated by an object at a given temperature and
spectral band to the energy emitted by a perfect radiator (blackbody) at the same
temperature and spectral band. The emissivity of a perfect blackbody is unity (1.00).
EMI/RFI Noise
Electro-Magnetic Interference/Radio Frequency Interference (EMI and RFI) may cause
disturbances to electrical signals within IR thermometers. EMI and RFI noise is most
commonly caused by devices by switching motors (air conditioners, power tools,
refrigeration systems, etc.).
Far Field
A measured distance substantially greater than the focus distance of the instrument;
typically greater than 10 times the focus distance.
A-2