Drives and Controls Magazine

Displacement sensors promise long ranges at low cost

10 February, 2010

The German sensor specialist Micro-Epsilon has come up with a new technology for measuring displacement which, it claims, offers high sensitivity and long operating ranges, at a low cost.

Unlike Hall Effect sensors, the patented Magnetic Displacement Sensor (MDS) is based on a linear relationship between the position of a target magnet and the output signal. It uses printed coils, thus avoiding the need for semiconductor manufacturing processes and making customer-specific adaptations easier.

The MDS (shown above) uses much smaller magnets than Hall sensors, cutting costs and simplifying installation. It also supports considerably longer measuring distances – currently up to 60mm.

Because the sensors are extremely sensitive, simple, low-cost evaluation circuits can be used. The output can be in the form of a PWM (pulse width modulated) signal which can be read by a microcontroller. Using an eddy current sensor as the technological core, fast, high-resolution versions are possible.

Micro-Epsilon originally developed the technology for use in appliances such as washing machines where it allows loads to be measured with a high resolution, while also monitoring spin cycles with high dynamics. But it says that the technology is applicable anywhere needing long measuring ranges and high resolution.