NOHKEN CG/CGM Series Capacitance Level Meter

Primary application

The phase detection method is ideal for high-precision measurements of all liquids.

Main features

Outstanding operability and ease of adjustment

Equipped with dielectric constant correction function

Improved adhesion resistance

Enables high-precision measurements

Compatible with a wide range of measurement objects

Operate the liquid crystal display

Operating principle

The basic oscillating circuit is a parallel resonant circuit of L (coil) and C (capacitance value generated between electrodes).
The oscillation frequency of this circuit is f =1/2π.
Assume that the oscillation frequency when there is no object under test is f1, f1=1/2π

C: Initial capacitance value (zero point)

In the presence of the object to be detected, C is increased to C + ΔC and the oscillation frequency becomes f2.
the frequency of f2can be expressed as follows.

f2 = 1 / 2π
C + ΔC: Capacitance value of the object to be detected (span point)

The frequency change from f1to f2is detected, converted into a current signal commensurate with the change (4to20mA DC) and output. In addition, since it is controlled by a microcomputer, it is possible to bias the output current value to zero and invert the output current value at the span point.