Compact eddy current measurement system sets new standards

Chris Jones, Managing Director at Micro-Epsilon UK comments: "The eddyNCDT 3005 sets new standards in terms of eddy current displacement measurement. The complete conditioning electronics has been miniaturised and mounted into a compact cylindrical housing, integrated into the sensor cable, one metre from the sensor head. Having the electronics remote from the sensor enables more compact sensor dimensions and higher operating temperatures, compared to sensors with integrated electronics.

"With a very competitive pricing structure, the system can be supplied from stock in lower quantities. Equally, for higher-volume applications, the system can be modified to suit individual OEM requirements. We expect to see interest from a wide range of companies that need to measure vibration, shaft runout, concentricity, gap, tip timing, eccentricity, oil film thickness and position, to micrometre level accuracies."

High-temperature version

Pressure, dirt, oil and high temperatures have almost no influence on measurement precision. The eddyNCDT 3005 has temperature-compensated electronics, which provides high measurement stability (0.05 per cent FSO) even in high or fluctuating ambient temperatures. The sensors are designed for ambient temperatures up to a maximum of 125degC but the series also includes an optional, high-temperature version for up to 180degC. The eddyNCDT 3005 controller, cable and sensor are pressure-resistant up to 10bar.

The eddyNCDT 3005 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 some offshore and marine applications (saltwater-resistant) due to its stainless steel construction.

A range of sensors are available with measuring ranges from 1mm up to 6mm for use on steel or aluminium measuring objects. Frequency response is 5kHz (-3dB) and temperature compensation range is from 10degC to +125degC.

Micro-Epsilon's range of eddy current sensors also includes the eddyNCDT 3001 series, 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 where the highest measurement performance is needed; for example, 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. Also, the eddyNCDT 3300 has many other potential uses such as vibration monitoring in motors, pumps, bearings and rotating machinery, or for measuring the thickness of strip or position control of strip in metal production.

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.

For more information on the eddyNCDT 3005, please visit the company's website at www.micro-epsilon.co.uk.