Made In The U.S.A. Since 1938
Lumenite Control Technology, Inc.
Engineers • Designers • Manufacturers
SHOWN Transmitters :
MLST-4220 Sanitary (left)
MLXT-4220 Industrial (right)
"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.
• 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 4-20mA
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