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Dial Instruments Pte Ltd
Level Measurement Solutions for Petrolchemical, Pharmaceutical,
Marine & General Industries
 
Subpage :: Masthead
Capacitive level sensors CG/CGS/CG65 (phase detection)

Capacitive level sensors CG/CGS/CG65 (phase detection)

CLSCG

Description

Applications
Virtually any liquids, solids and bulk solids
 

Features
  • Easy programming by push buttons
  • Multifunctional with microcomputer
  • First level switch to have status indicating LCD
  • Improved buildup prevention performance
  • Extremely reliable
 

Principle of Operation
Principle of Operation

The basic oscillator circuit is of the parallel resonance circuit with L (coil) and C (capacitance between the electrodes).
The oscillation frequency (f) of this circuit is : f = 1/2 π √LC.
The frequency without material around the sensor (f1) is: f1 = 1/2 π √LC, where C is the capacitance without material around the sensor (zero point).
With material around the sensor, the capacitance increases (C+ΔC), and the frequency (f2) is: f2 = 1/2 π √L(C+ΔC), where C+ΔC is the capacitance with material around the sensor (span point).
The sensor detects the frequency change from f1 to f2, and actuates the relay. The frequency range is divided into 8 segments (between zero and span), and the set and reset points assigned on a desired segment, which means high limit, low limit and hysteresis can be programmed.