Accuracy
The maximum positive and negative % deviation over the
total span.
ANSI
American National Standards Institute.
ATEX
ATmospheric EXplosive
European regulations
governing the use in hazardous areas.
Blocking Distance
The distance between the top of the probe
(fiducial) and the point at which meaningful measurement can
be expected.
CE
Conformité Européene
Standards and performance
criteria for the new European Union.
CENELEC
Comité Européen de Normalisation Electrotechnique
European organization that sets standards for electrical equipment.
Coaxial Probe
The most sensitive waveguide in the TDR family.
The concentric design (rod inside a tube) is useful in very low
dielectric media that are clean and have low viscosity.
CSA
Canadian Standards Association
Canadian third-party agency
that qualifies the safety of electrical equipment.
Damping
Amount of time required to reach 99% of actual level
change.
Default Screens
The main position of the menu structure that
displays the primary measurement values of LEVEL, % OUTPUT,
and LOOP. The transmitter returns to this position after 5 minutes
of inactivity.
Dielectric Constant (
ε
)
The electrical permittivity of a material.
The units are farad/meter.
DVM/DMM
Digital Volt Meter/Digital Multimeter.
Electromagnetic Energy
The radiation that travels through space as
electric and magnetic fields varying with position and time. Examples
in increasing frequency: radio waves, microwave, infrared light, visi-
ble light, ultraviolet light, x-rays, gamma waves, and cosmic waves.
EM
See Electromagnetic Energy.
EMI
Electromagnetic Interference
Electrical noise caused by electro-
magnetic fields that may affect electrical circuits, particularly low-
power electronic devices.
EN
European Normal
Committee guidelines in EC countries that
take precedence over local, country guidelines.
ENV
Preliminary EN guidelines, or pre-standards.
Ergonomic
A mechanism that considers human capability in its
design or function.
ETS
Equivalent Time Sampling
Process that captures high speed
electromagnetic events in real time (nanoseconds) and reconstructs
them into an equivalent time (milliseconds).
Explosion Proof Enclosure
An enclosure designed to withstand an
explosion of gas or vapor within it and prevent the explosion from
spreading outside the enclosure.
Factory Sealed
A third-party-approved Explosion Proof seal
installed in the unit during manufacturing. This alleviates the end
user from installing an external XP seal adjacent (within 18") to the
device.
Fault
A defect or failure in a circuit. The current (mA) value unit
defaults to 3.6, 22, or Hold when a diagnostic condition occurs.
Feedthrough
A small connecting cavity between the main housing
compartments, carrying the cable that supplies the operating energy
to the measurement circuitry and returns the output value propor-
tional to level. This cavity is potted to maintain the environmental
isolation between the two compartments.
Fid Gain
Fiducial Gain
Amount of amplification added to Fiducial
(baseline) area of measurement.
Fiducial
The reference signal at the top of the probe.
Fiducial Tick
A value related to baseline timing that adjusts the
timing window, which enhances resolution. (Factory setting).
FM
Factory Mutual
American third party agency that qualifies the
safety of electrical equipment.
Four Wire
An electronic instrument design that uses one set of
wires to supply power (120/240 VAC, 24 VDC) and another set
to carry the process measurement signal (4–20 mA). Also called
Line-powered.
FSK
Frequency Shift Keying.
See HART.
Gain
Amplification adjustment to attain optimum performance in
various product dielectric ranges. (Factory setting).
Ground
An electrical connection to the Earth’s potential that is
used as a reference for the system and electrical safety.
Grounded
A state where no electrical potential exists between the
ground (green) connection on the transmitter and the Earth or
system ground.
Guided Wave Radar
See TDR.
HART
Highway Addressable Remote Transducer.
Protocol that uses
the Bell 202 frequency shift keying (FSK) method to superimpose
low level frequencies (1200/2000 Hz) on top of the standard 4–
20 mA loop to provide digital communication.
HART ID
See Poll Address.
Hazardous Area
An area where flammable gases or vapors are or
may be present in the air in quantities sufficient to produce explosive
or ignitable mixtures.
IEC
International Electrotechnical Commission
Organization that
sets international standards for electrical devices.
Increased Safety
Designs and procedures that minimize sparks, arcs,
and excessive temperatures in hazardous areas. Defined by the IEC as
Zone 1 environments (Ex e).
Interface: Electrical
A boundary between two related electronic
circuits.
Interface: Process
A boundary between two immiscible liquids.
Intrinsically Safe Ground
A very low resistance connection to a
ground; in accordance with the National Electrical Code (NEC,
ANSI/NFPA 70 for FMRC), the Canadian Electrical Code (CEC for
CSA) or the local inspector.
Glossary
64
57-600 Eclipse
®
Guided Wave Radar Transmitter
