Glossary-2 Raynger 3i Series Operator's Manual
DIG/ANA
Digital/Analog switch. On units with this
feature, a user can switch between digital
and analog outputs.
Digital Data Bus
A means for transmitting coded digital data
on a common buss in accordance with a stan-
dard format such as RS-232 or IEEE-488.
Digital Output Interval (DOI)
The time interval between variable length
digital message transmissions containing
temperature and system status information.
DIN
Deutsches Institut für Normung (DIN). 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 stan-
dard test method E 1256-88).
EMC
Electro-Magnetic Compatibility. Resistance
to electrical signal disturbances within IR
thermometers.
Emissivity
The ratio of infrared energy radiated by an
object at a given temperature and spectral
band to the energy emitted by a perfect radi-
ator (blackbody) at the same temperature
and spectral band. The emissivity of a per-
fect blackbody is unity (1.00).
EMI/RFI Noise
Electro-Magnetic Interference/Radio
Frequency Interference. EMI and RFI may
cause disturbances to electrical signals with-
in IR thermometers. EMI and RFI noise is
most commonly caused by devices with
switching motors (air conditioners, power
tools, refrigeration systems, etc.).
°F (Fahrenheit)
Temperature scale where °F = (°C x 1.8) + 32
= °R - 459.67.
Far Field
A measured distance substantially greater
than the focus distance of the instrument;
typically greater than 10 times the focus dis-
tance.
Field of View (FOV)
The region, at the target, measured by the IR
thermometer. Typically presented by giving
the spot diameter as a function of distance
from the instrument. Also presented as the
angular size of the spot at the focus point.
See Optical Resolution.
Filter (Optical)
Refer to Spectral Filter or Neutral Density
Filter.
Focus Point (or Distance)
The distance from the instrument where the
optical resolution is greatest.
Full Scale
The maximum of the temperature range or
output signal.
Full Scale Accuracy
A convention for expressing the accuracy as a
percentage of an instrument’s (highest) full
scale temperature.
Gray Body
A radiating object whose emissivity is in con-
stant ratio (not unity) at all wavelengths to
that of a blackbody at the same temperature,
and does not transmit infrared energy.
HAL
High Alarm. Units with this feature can
sound an alarm when they sense that a user-
defined high temperature has been reached.
Hertz (Hz)
Units in which frequency is expressed.
Synonymous with cycles per second.
IECInternational Electrotechnical Commission; a
European organization that coordinates and
sets standards among the European
Community.
IEEE-488
A communications format standard. See dig-
ital data bus.