New magneto-inductive displacement sensors for OEMs

The latest addition to this family of sensors is a new, slimline version with an M18 stainless steel housing. The MDS-45-M18-SA provides a longer measuring range, from 20mm up to 55mm, depending on the size of the magnet. This new design also allows increased frontal pressures of up to 400bar. An additional groove around the housing enables the measuring system to be sealed with an O-ring, protecting the sensor from oil, seawater and other aggressive substances. Typical applications for the MDS-45-M18-SA include hydraulic valves, attenuators and subsea hydraulics.

Micro-Epsilon's mainSENSOR range operates on the magneto-inductive measuring principle. The sensor coil is supplied with alternating current, resulting in a primary magnetic field. This magnetic field induces eddy currents in the electrically conductive material arranged opposite the coil. In the field of the eddy current sensor is a special film, which attenuates the eddy current sensor depending on the strength of the magnetic field. Using this method, a linear relationship between the distance to the magnet and the output signal can be established. As printed coils can be used inside the sensor, manufacturing does not rely on any semiconductor processes.

Chris Jones, Managing Director at Micro-Epsilon UK Ltd, states: "The sensors combine the robustness and proven measurement performance of our eddy current sensor technology with the latest printed coil and permanent magnet technology. This means that customers not only benefit from having an extremely compact design relative to the measuring range, but the sensors also provide an attractive price-performance ratio for mid-to-high volume OEM applications.

"Due to simplified electronics, Micro-Epsilon is able to produce low-cost versions of the sensor with printed circuit boards and basic analogue outputs, or can combine this version with a microprocessor to create a digital output sensor, including PWM, CANbus and other digital interfaces. The electronic circuit design and production is undertaken in-house at Micro-Epsilon's PCB production facility, giving the company full design flexibility for the electronics, combined with complete control over product quality."

Although the mainSENSOR uses a permanent magnet as the target, unlike Hall Effect sensors, it does not suffer from relatively low sensor accuracy or high temperature drift. mainSENSORs use Micro-Epsilon's patented measuring method, which is based on a linear relationship between the position of the permanent magnet and the output signal.

As well providing a simplified displacement measurement technique, mainSENSOR also offers very high basic sensitivity, excellent temperature stability (low thermal drift) and a maintenance-free, wear-free measurement product.

Industrial-grade sensors

Chris Jones continues: "Micro-Epsilon has developed the technology even further over the last 18 months, resulting in a growing family of industrial-grade, standard displacement measurement sensors, which are proving invaluable in many OEM applications, including hydraulics, automotive, off-highway vehicles, subsea oil and gas hydraulics, and special purpose machines."

There are now three standard sensor ranges in the mainSENSOR family, including the new slimline MDS-45-M18-SA range.

The MDS-45-M30-SA has a 55mm measuring range and an M30 cylindrical, barrel-type stainless steel housing. The sensor weighs 15g and can operate in temperatures up to 80degC. The signal output provides 4-20mA or 2-10V DC.

An alternative is the OEM version, the MDS-45-K-SA, a miniature flat rectangular PCB version of the sensor with a plastic housing, countersunk M4 screw connection and a 55mm measuring range. Signal output is 4-20mA or 2-10V DC.

For more information on Micro-Epsilon's mainSENSOR range of magneto-inductive displacement sensors, email [email protected]. To find out more, visit the website at www.micro-epsilon.co.uk.