Compact eddy current sensor

Paul Boughton

Precision sensor manufacturer Micro-Epsilon UK has launched a compact, high performance eddy current sensor with integrated electronics. Although the sensor is similar in size to a typical proximity or inductive sensor, its measuring performance is much greater, making it ideal for OEM applications.

All conditioning electronics on the new eddyNCDT 3001 eddy current sensor are completely integrated into the sensor housing. However, the compact M12 dimensions do not mean lower performance; the sensor’s temperature-compensated electronics provides high measurement stability (0.03% FSO) even in fluctuating ambient temperatures.

The eddyNCDT 3001 is factory-calibrated for both ferrous and non-ferromagnetic materials, which eliminates the need for any onsite calibration. The robust IP67 sensor design, combined with the true eddy current measuring principle, enables measurements in harsh industrial environments (oil, pressure, dirt, dust), as well as for offshore and marine applications (saltwater-resistant).

The sensor has a measuring range of 4mm and a frequency response of 5kHz (-3dB). Temperature compensation range is from 0°C to +70°C.

Eddy current sensors from Micro-Epsilon are designed for non-contact measurement of displacement, distance, position and vibration. As well as the eddyNCDT 3001 sensor, Micro-Epsilon’s range of eddy current sensors also includes the eddyNCDT 3100 series, the eddyNCDT 3300 series, turbocharger speed sensors (turboSPEED DZ140) and the Spindle Growth System (eddyNCDT SGS4701).

The eddyNCDT 3300 series are used extensively in automotive R&D, where they are used to measure valve stroke, injection needle movement, cylinder head breathing, lubricating gap, oil film thickness, crankshaft concentricity and axial movement of crankshafts. The sensors have many other potential uses, such as vibration monitoring of the strip in steelworks, measuring the thickness of foil and in edge control or positioning.

In addition, the eddyNCDT 3100 series represents a world first in eddy current displacement measurement. With its Smart Sensor Auto Calibration system, the sensor can be connected easily and quickly to the 3100 controller. All calibration data is then automatically uploaded from the sensor to the controller, with no need for any lengthy calibration.

All calibration data required for both ferrous (St37) and non-ferrous (aluminium) target materials is stored in the sensor before it is shipped. User-specific target materials can also be measured accurately using Micro-Epsilon’s push-button, 3-point linearisation.

The eddyNCDT 3100 controller is equipped with many new features, including Ethernet connection for output signal and configuration. The configuration of the controller can be performed from the user’s web browser by simply typing in the controller IP address – no additional software needs to be downloaded. All controllers are supplied with a default IP address that the user can amend later to a specific IP address.