Kenco Engineering KMD Transmitter - Manual (Page 4)

3. TRANSMITTER FEATURES
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• CSA approved explosion-proof enclosure
• Digital Display for zero and span settings and readout
• Readout is updated every 3 seconds
• Readout available as a % of span, a 4-20 mA output or any unit of
measure
• Adjustments may be made using a HART ® hand held communicator
• Repeatability is .005% full span or .005 inches
• Temperature range: - 40°F to 300°F (call KENCO for higher temperature
requirements)
• No maintenance required
• Immune from electrical and mechanical noise
4. PRINCIPLE OF MAGNETOSTRICTION
The level transmitter is composed of 2
concentric members. The outermost
member is a protective 316 stainless
chamber that withstands aggressive
environments. Inside of the chamber
is the waveguide, a formed element
constructed of a proprietary
magnetostrictive material.
A pulse is induced in the waveguide by
the momentary interaction of 2
magnetic fields, one from an electric
current pulse launched along the
waveguide and the other from the
magnets inside the float. This
interaction produces a strain pulse
that travels along the waveguide. The
location of the magnet inside the float
is determined by measuring the
elapsed time between the launching of
the electronic pulse and the detection
of the strain pulse that travels along
the waveguide.
The location of the
magnet inside the float is determined
by measuring the elapsed time between
the launching of the electronic pulse
and the detection of the strain pulse by
the sensor head.
The time period
measurement is used to produce an
output reading of the float location.