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.

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Capacitance Level Transmitters

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Level Controls