Since the year 2000, our partner WayCon is engaged in the development and production of eddy current sensors.
A wide field of application is generated by the TX series, which was developped in particular for high-end automation and robotics. The WayCon engineers continuously adapt and develop the eddy current sensors further to your special needs. The new TX Series is a fully digital device - incorporating USB, CAN and a high-speed analogue interface.
Eddy current probes are particularly suitable devices for non-contact measurements on metallic targets. Typical applications are measurements on rotating shafts for the detection of imbalance, vibration, out-of-roundness, air gap, radial/axial runout, and much more besides.
The extremely high resolution up to level of 20nm enables the smallest of amplitudes to be detected. The probes are designed for temperatures up to 185°C, and are optimised for the entire temperature range with regard to temperature drift.
|PRODUCT||EddyCurrent-Basic Module TX, 1 or 2 channel device|
|ANALOG OUTPUT||0...10V, 0...5V, ±5V, (0)4...20 mA|
|PROBE MEASURE RANGES||0...0,5mm / 0...2mm / 0...3mm / 0...4mm / 0...5mm / 0...10mm|
|PROBE HOUSING SIZES||diameters: 5mm / 8mm / 12mm / 14mm / 18mm / 30mm|
|PROBE CABLE LENGTH||standard length 3 m / 6 m, customised length up to 20 m|
• Measurement ranges 0...10 mm
• One or dual-channel device
• Analog Outputs: 0...10V, 0...5V, ±5V, (0)4...20 mA
• CAN bus: Data transfer via CAN bus for diverse systems with multi channel measurement.
• USB port: Interface for PC and data transfer. Usage of eddyLAB software.
• Benefit 1-channel unit: highest dynamic performance. The output sampling rate is 124 kS/s.
• eddy probe linearity ±0,15% of measure range
• eddy probe operating temperature: -60...+185°C
• Unaffected of non-metallic media in the measurement room (e.g. water, oils, fouling, synthetics)
• Distance measurement on static and rotating objects
• Measurement of unbalance and vibration
• Contactless quality check in automation
The basic principle
The principle of measurement bases on a DSP-driven oscillating circuit made up of the probe inductivity) and a interconnect capacitance. This circuitry is attenuated in the presence of metallic objects. The oscillating circuit generates magnetic field lines - these induce eddy currents on the surface of conductive objects. The eddy currents counteract their cause and attenuate the amplitude of the oscillating circuit. This effect is decoupled from the oscillating circuit a fed towards further signal processing.
Outstanding temperature coefficient - Zero TC
A remarkable feature is the TX-Serie's temperature coefficient (TC). The temperature coefficient is optimized in a range between -60°C..185°C. For certain boundary conditions the position will be constant at ambient temperature and 150°C. This matter of fact can interpreted as Zero TC. Particularly when it comes to high-resolution measurements this effect is of seminal importance.
Minimal probe drift
Every probe produced in WayCon's facility line is treated with a thermal finishing procedure of a 12- hour duration (burn-in). This procedure minimises aging and drift. The probe is then finally calibrated in the WayCon laboratory before delivery.
The basic measuring principle of the eddy current sensors is based on the fact that the coil generates a magnetic alternating field in the sensor head whose lines of flux leave from the sensor head which pass object, and shut again. Besides, the measuring field (magnetic alternating field) in the electrically leading-capable object generates the eddy current which entail joule losses.
These eddy current losses in the object increase with lower distance. On the input side of the electronics the eddy current losses about the change of the impedance are evaluated. A output signal proportional to distance is formed as for example 0... 10 V or 4... 20 mA.
Main operational area of the eddy current sensors is the check of rotating shafts on imbalance, vibration, unroudness as well as radial and axial runout. For the radial measurement a level coat surface is optimum. Here the relative movement can be measured with a sensor between sensor and shaft.
Arranging two sensors in 90° corner, one gets differentiated explanation about unroudness and radial runout.
For structured surfaces, as for example with gear wheels or groove shafts, we offer the possibility to fade out either the tooth flank by means of software and to spend the average and to receive therefore information about the radial movement, or to grasp the tooth flanks individually in the maximum values. Here explanation can be received over broken out teeth or shovels or wear.
For example, an investigation of the shaft deflection or radial and axial misalignment can be carried out in the vehicle gear with different load states in the test bench or in the driving attempt. Case distortions can be measured.
With constantly pursued machines, as for example with turbo-generators in power stations, the state of the bearrings can be supervised. Vibrations beyond the specified area are recognised and the machine can be brought in a reliable operational state, before it comes to cost-intensive and time-luxurious damages.
Furthermore a wear measurement of the main shaft is possible and a servicing interval can be included in the maintenance plan. The behaviour of the rotor can be examined under different load states or with different oleograph in the lubrication gap of the bearrings.
The new WayCon eddy current sensor T10 with 10 mm of measuring range offers sensible detailed solutions for the connection.
The sensor can be twisted about a standard-key width SW24. For radial inaccessible situations in thread canals the sensor can be mounted by cylinder drillings and a wide groove without damaging the cable.