Lumenite® Control Technology, Inc. ENGINEERS • DESIGNERS • MANUFACTURERS
Level Transmitters
Capacitance Level Measurement Explained
The series 4220 microprocessor based capacitance level transmitters operate on the capacitance principle of continuous level measurement. In the simplest terms, the output signal in milliamps is dependent on the capacitance formula :
Dielectric Constant * Area of Parallel Plates ÷ Distance Between Parallel Plates 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 of 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.
About Our Level Transmitters
MLST And MLXT-4220
continuous level transmitters are for sanitary and industrial level transmitter applications. A capacitance level transmitter provides 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 continuous level transmitters and temperature transmitters 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.
Standard Specifications
• Resolution to better than 1 part in 10,000
• Accuracy and repeatability to less than 0.1% of span
• Microprocessor based capacitance level transmitters 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 continuous level controls sensing probe
MLXT - 4220 - P3/4" - industrial level transmitter,
Approved & Certified : UL, CSA & 3A
