E3A-JA3A-F11 Datasheet, PDF (37/60 Pages) Magnetrol International, Inc. – Liquid Level Displacer Transmitter

Wiring Board
Moving
LVDT Core
Printed
Circuit Board
Enclosing Tube
Electronics
Enclosure
LVDT
Display
Keypad
Stem
8.0 Reference Information
This section presents an overview of the operation of the
E3 Electronic Modulevel Displacer Level Transmitter,
information on troubleshooting common problems, listings
of agency approvals, lists of replacement and recommended
spare parts, and detailed physical, functional, and perform-
ance specifications.
8.1 Description
The E3 Modulevel is a level transmitter which utilizes sim-
ple buoyancy principles in combination with a precision
range spring and a highly accurate LVDT (linear variable
differential transformer) to detect and convert liquid level
movement into a stable output value. The electronics are
housed in an ergonomic, dual-compartment enclosure
which is angled for ease of wiring and calibration.
Range Spring
8.2 Theory of Operation
Displacer
External cage
Figure 17
Electronic Modulevel
Components
The Electronic Modulevel Displacer Level Transmitter relies
on the principles of buoyancy to convert mechanical move-
ment to an electronic output. See Figure 17.
8.2.1 Displacer/Range Spring
According to Archimedes principle, the buoyancy force act-
ing on an object immersed in liquid is equal to the mass of
the liquid displaced. As the level changes, the volume of dis-
placer submerged in the liquid changes, thus varying the
buoyancy force acting on the displacer. This change is
detected by the precision range spring from which the dis-
placer hangs, causing it to elongate or compress. The change
in spring length causes movement of a special LVDT core
which is mounted on a rigid stem attached to the spring.
8.2.2 LVDT
E3 Modulevel utilizes highly precise LVDT technology to
convert the movement of the LVDT core within the LVDT
to a stable output value. The position of the core with
respect to a primary and two secondary windings within the
LVDT, induces a voltage in each winding. The comparison
of the induced voltages within the microprocessor of the E3
results in very accurate level output.
48-640 E3 Modulevel Displacer Level Transmitter - FOUNDATION fieldbus^™
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