About The Capacitance Principal . . .
"The Capacitance Principal" of level measurement says the output signal in milliamps is dependent on
the formula :
Capacitance (C) = Dielectric Constant (K) * Area of
Parallel Plates (A) ÷ Distance Between Parallel
Plates (D) or C = KA / D.
In a level measurement application, the dielectric
constant “K” is a value greater than 1. The value “A”
is dependent on the diameter and length the level
probe. The value “D” is the distance from the probe
to the tank wall, ground reference probe or
concentric tube. Consequently, capacitance (C) and
the resultant mA output increases as the dielectric
constant increases, the probe diameter and length
increases, and the distance from the probe to tank
wall (ground probe or tube), decreases.
MLST and MLXT - 4220 capacitance level transmitters are for sanitary and industrial level
transmitter applications. They provide a continuous 4-20mA, 20-amA, 1-5VDC or 5-1VDC
analog output proportional to the material level in any shaped tank. They can be used for
conductive, non-conductive liquids and moist granular solids.
MLST and MLXT - TEMP - 4220’s are combination level / temperature transmitters are for
sanitary and industrial applications. In addition to having all of the standard specifications,
they provide 2 separate 4-20mA outputs measuring level and temperature with one probe and
one tank connection. Temperature ranges from -100˚ to 1,000˚F.
About Lumenite® Capacitance Level Transmitters
• Resolution to better than 1 part in 10,000
• Accuracy and repeatability to less than 0.1% of span
• Microprocessor based transmitter with on board digital to analog
conversion assuring negligible output current error of 0.003%
• Linearity of better than 0.003% over industrial temperature range of -20˚F to 160˚F
• Designed with most up to date surface mount, integrated circuits and components
• Standard range of 0.0001 picofarads to 15,000 picofarads allowing the 4220 to span 402-mA
over 1 inch of water, (high sensitivity) or hundreds of feet of water (low sensitivity)
• Non interacting zero and span
• Cancel Coat™ circuitry and superior resolution eliminate the readout errors cause by
conductive coatings on the sensing probe
Standard Specifications . . .
Lumenite® Control Technology, Inc.
Engineers • Designers • Manufacturers
Capacitance Level Transmitters
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