Operating Instructions for Digital Mass Flow Meter and Controller Model: DMS

Kobold Messring GmbH Chapter 1 Introduction
Figure 1-2. Flow Measuring Principle
Figure 1-3. Sensor Temperature Distribution
Figures 1-2 and 1-3 show the mass flow through the sensor tube as
inversely proportional to the temperature difference of the coils. The
coils are legs of a bridge circuit with an output voltage in direct proportion
to the difference in the coils’ resistance; the result is the
temperature difference ( ΔT). Two other parameters, heat input (H)
and coefficient of specific heat (Cp) are both constant. Through careful
design and attention to these parameters, this output signal is
made linear over the transducer’s normal operating range (Figure 1-4).
As a result, the measured flow through the sensor tube is directly
proportional to the gas flow in the main body.
DMS 1-5