46
48-635 E3 Modulevel
®
Displacer Level Transmitter
Accuracy
The closeness of agreement between the result of
measurement and the true value of the measure (inaccuracy
equals the maximum positive and negative % deviation over
the total span).
ANSI
American National Standards Institute.
ATEX
ATmospheres EXplosive
European regulations
governing the use of equipment installed in hazardous
locations.
CE
Conformité Européene
Standards and performance
criteria for the new European Union.
CSA
Canadian Standards Association
Canadian, third
party agency that qualifies the safety of electrical equipment.
Damping
The imposed delay between level change and the
corresponding output signal change; often used to smooth
unwanted output variations.
Default Screens
The initial position of the menu structure
that displays the primary measurement values of
Level/IfcLevel/SpecGrav, %Output, Loop and to which it
returns after 5 minutes of inactivity.
Diagnostics
Three levels of error messages; Fault, Warning
and Information.
Displacer
A sensing element that is heavier than the liquid
in which it is used and provides the volume necessary to vary
the buoyancy force acting on the unit.
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, visible light, ultraviolet light,
x-rays, gamma waves, and cosmic waves.
EM
See Electromagnetic Energy.
EMI
Electromagnetic Interference
Electrical noise caused
by electromagnetic fields that may affect electrical circuits,
particularly low-power electronic devices.
EN
European Normal
Committee guidelines in EC coun-
tries that take precedence over local and/or country guide-
lines.
Enclosing Tube
Non-flexing pressure boundary component
that isolates the process from the electronics.
ENV
Preliminary EN guidelines, or pre-standards.
ESD Electrostatic Discharge
The release of stationary elec-
trical energy which can cause damage to electronic compo-
nents.
Explosion-Proof Enclosure
An enclosure designed to with-
stand 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
The highest level in the hierarchy of diagnostics
annunciating a defect or failure in circuitry or software that
preclude reliable measurement. The current (mA) value unit
defaults to 3.6, 22, or Hold and a message is displayed on the
rotating screen. Further information can be obtained by view-
ing the Status or Diagnostic (Factory Menu) screens.
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 proportional to the level.
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.
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.
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).
Inductor
A coil across which a voltage is induced as a result
of the variation of the current through the coil.
Information (message)
The lowest level in the hierarchy of
diagnostic conditions providing operational factors that are
not critical to measurement. Further information can be
obtained by viewing the Status or Diagnostic (Factory Menu)
screens.
Interface: Electrical
A boundary between two related,
electronic circuits.
Interface: Process
A boundary between two or more
immiscible liquids.
Intrinsically Safe Ground
A very low resistance connecting
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
