SFT Weighing Technology

Vibrating Wire Technology

The relationship between a wire’s tension and its resonant frequency has been understood for a long time. With the advent of electronics, it became obvious that a vibrating wire could be used as a variable oscillator or force sensor. Today it is used in high-performance all-digital weighing scales. In such a system, the force to be measured will directly govern the tension of the wire, and the frequency of vibration will be detected and evaluated to obtain the result.

The SFT weighing module takes advantage of the dependency of a vibrating wire's resonant frequency on its tension to measure applied load. The applied load is transmitted to the wire by mechanical means, causing a change in the resonant frequency from which the value of the applied load is computed by the onboard microprocessor. A fully calibrated (linearized, spanned and temperature compensated) signal is transmitted via RS 485 serial communication to the controller.

Vibration Immune Weighing

Achieving high gravimetric feeding performance on the process line requires discriminating between weight data and the contaminating effects of inertial forces induced from ambient vibration and shock. Coperion K-Tron’s exclusive dynamic digital filtering algorithm continuously identifies and extracts spurious inertial components from the weight measurement, even in severe process environments.