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Inductive sensors provide high resolution measurement for even the dirtiest environments. These advantages have made inductive sensors indispensable for many machine builders, production managers, or precision metrology applications.

Also know as Eddy current sensors, these sensors provide advantages including non-contact measurement, nanometer resolution and high-speed for the most challenging applications. As precision engineers, we can provide expert help and unique solutions matched to your application. Whether you need to measure distance, thickness, in vacuum or wireless, to name a few requirements, we have solutions and expertise to match your needs.

At a glance

  • Highest resolution at the highest bandwidth in the industry.
  • Tolerance of dirty environments.
  • Analogue and digital outputs.
  • Simple user interface.
  • High vacuum compatability.
  • Higher temperature environments.
  • Customisation based on your requirements.
Read more
02.3 Inductive measurement probes
State-of-the-art sensors can be supplied standard or made to order.
Inductive drivers overview
ECL202,ECL101,ECA101
ECL150_Ombouw_Probe
ECL150
ECW110
ECW110
ECA110_2-1
ECA110
Driver name
ECL202 ECL150 ECL101/ECL110 ECW110 ECA101 ECA110
Max. bandwidth 15 kHz 15 kHz 80 kHz 1kHz 10kHz 10kHz
Measurement range 0.25mm - 15 mm 0.50mm - 15 mm 0.50mm - 15 mm 2mm - 3,5 mm 0.50mm - 15 mm 0.50mm - 15 mm
Typical linearity 0,2% 0,2% 0,5% F.S. 0,5% F.S. Non-linear Non-linear
Resolution at 15kHz Non-ferrous 0,007%, Ferrous 0,009% Non-ferrous 0,007%, Ferrous 0,009% Non-ferrous 0,009%, Ferrous 0,011% 100nm @1kHz Non-ferrous 0,02%, Ferrous 0,02% Non-ferrous 0,02%, Ferrous 0,02% @10kHz
Zero/Offset adjust Yes Yes Yes No Yes No
Typical thermal drift 0,01% F.S.*/C 0,01% F.S.*/C 0,04% F.S.*/C 0,04% F.S.*/C 0,04% F.S.*/C 0,04% F.S.*/C
LED range indicator Yes Yes Yes No Yes No
Other features Bandwidth: 100 Hz, 1 kHz, 10 kHz, 15 kHz (user selectable) Bandwidth: 250 Hz, 1 kHz, 10 kHz, 15 kHz (user selectable) Two environmental ranges - Standard to 125C, High to 200C Two environmental ranges - Standard to 125C, High to 200C Embeddable unit, no user adjustment
*F.S. = full scale
ECL202 ECL150 ECL101/ECL110 ECW110 ECA101 ECA110
Info

The ECL202 eddy-current sensor system delivers exceptional resolutions, down to 10nm, and bandwidths up to 15kHz. The electronics of the ECL202 are based on the latest FPGA digital technology, delivering excellent noise immunity and very high stability. The system provides a linear analogue voltage output (0 - 10 Volt) proportional to changes in the target position and a digital (switched) output with a user programmed switching threshold.

Probe choices
Probe model Range Type Range mm Near gap mm Material Type

Resolution nm @100Hz

@1 kHz @10 kHz @15 kHz ECL202e @15kHz Thermal drift probe %F.S./C Thermal drift driver  
U3 Fine 0,25 0,05 Non-ferrous 10 15 25 30  - 0,04 0,04  
    0,25 0,05 Ferrous 15 25 40 50 - 0,06 0,10  
  Standard 0,50 0,25 Non-ferrous 25 30 60 65 400 0,04 0,04  
    0,50 0,25 Ferrous 30 40 100 110 400 0,08 0,08  
U5 Fine 0,625 0,25 Non-ferrous 30 35 70 75 - 0,04 0,04  
    0,625 0,25 Ferrous 40 50 75 80 - 0,8 0,04  
  Standard 1,25 0,25 Non-ferrous 45 65 140 150 400 0,04 0,1  
    1,25 0,025 Ferrous 80 120 240 260 400 0,1 0,1  
U8 Fine 1,00 0,35 Non-ferrous 20 30 50 60 - 0,02 0,04  
    1,00 0,35 Ferrous 50 60 100 110 - 0,04 0,04  
  Standard 2,00 0,35 Non-ferrous 40 60 135 145 400 0,02 0,04  
    2,00 0,35 Ferrous 70 80 180 200 400 0,04 0,04  
U12 Fine 1,60 0,60 Non-ferrous 40 50 100 110 - 0,01 0,01  
    1,60 0,60 Ferrous 50 70 120 130 - 0,02 0,02  
  Standard 3,50 0,60 Non-ferrous 60 90 210 240 400 0,02 0,01  
    3,50 0,60 Ferrous 100 170 250 300 400 0,03 0,01  
U18 Standard 5,00 0,75 Non-ferrous 80 130 300 340 400 0,01 0,01  
    5,00 0,75 Ferrous 130 200 390 450 500 0,01 0,01  
U25 Standard 8,00 1,25 Non-ferrous 180 250 500 600 600 0,01 0,01  
    8,00 1,25 Ferrous 180 250 500 600 600 0,01 0,01  
U38 Standard 12,50 1,50 Non-ferrous 200 350 700 800 800 0,01 0,01  
    12,50 1,50 Ferrous 200 350 700 800 800 0,02 0,01  
U50 Standard 15,00 2,00 Non-ferrous 300 400 800 900 900 0,01 0,01  
    15,00 2,00 Ferrous 300 450 900 1000 1000 0,01 0,01  
Probe brochure
application example

Reactor-Plate

Reactor plate oxide thickness - the customer required to  measure the surface oxide layer thickness of nuclear fuel rods.  This thickness is used to confirm the remaining lifetime of the rod, optimising the economic performance of the fuel. As it also see flaws in the oxide layer, it is used for root cause analysis of failed fuel rods and to confirm fuel behaviour models.

Info

The ECL150  system provides up to 8 channels of high resolution position and displacement measurement in a small package. It is ideal for multi-sensing applications in industrial environments such as synchronized x,y,z positioning; 5 degrees of freedom shaft measurement or multi-point thickness measurement.

Probe choices
Probe model Range mm Near gap mm Material Type

Resolution nm @250Hz

@1 kHz @10 kHz @15 kHz ECL150e @15kHz Thermal drift probe %F.S./C Thermal drift driver  
U3 0,50 0,05 Non-ferrous 35 45 60 65 400 0,04 0,04  
  0,50 0,05 Ferrous 60 80 100 110 400 0,08 0,08  
U5 1,25 0,25 Non-ferrous 75 100 140 150 400 0,04 0,10  
  1,25 0,25 Ferrous 130 180 240 260 400 0,10 0,10  
U8 2,00 0,35 Non-ferrous 75 100 135 145 400 0,02 0,04  
  2,00 0,35 Ferrous 100 125 180 200 400 0,04 0,04  
U12 3,50 0,60 Non-ferrous 120 160 210 240 400 0,02 0,01  
  3,50 0,60 Ferrous 150 200 250 300 400 0,03 0,01  
U18 5,00 0,75 Non-ferrous 170 240 300 340 400 0,01 0,01  
  5,00 0,75 Ferrous 230 300 390 450 500 0,01 0,01  
U25 8,00 1,25 Non-ferrous 330 430 600 650 650 0,01 0,01  
  8,00 1,25 Ferrous 360 480 650 750 750 0,01 0,01  
U38 12,50 1,50 Non-ferrous 600 750 1000 1200 1200 0,01 0,01  
  12,50 1,50 Ferrous 650 800 1100 1300 1300 0,02 0,01  
U50 15,00 2,00 Non-ferrous 750 1000 1300 1400 1400 0,01 0,01  
  15,00 2,00 Ferrous 800 1100 1400 1500 1500 0,01 0,01  
Probe brochure
application example

Machine Metrology Frame

Machine tool metrology frame - 24 sensors were integrated into a machine tool bed to enable real time measurement of thermal and work piece related deformations. Wireless probes were employed to ease integration and provide a cost effective smart metrology solution.

Info

Where precision measurement is required for high speed applications, the ECL101 delivers  exceptional bandwidths up to 80kHz. Typical examples of high speed applications include measurement of motion or thermal growth of high speed spindles; observation of high speed vibrations or ultrasonic applications. The system can be calibrated in the field. For multi-channel applications, the ECL101 is available as a system of stacked circuit boards for maximum density in OEM applications. Up to eight channels can be ordered as a single ECL110 system.

Probe choices
Probe model Range mm Near gap mm Material Type Resolution nm @1 kHz @10 kHz @80 kHz  
U3 0,50 0,05 Non-ferrous 30 60 200  
  0,50 0,05 Ferrous 40 80 300  
U5 1,25 0,25 Non-ferrous 60 100 250  
  1,25 0,25 Ferrous 90 150 400  
U8 2,00 0,35 Non-ferrous 100 160 400  
  2,00 0,35 Ferrous 130 210 500  
U12 3,50 0,60 Non-ferrous 200 280 700  
  3,50 0,60 Ferrous 260 350 1200  
U18 5,00 0,75 Non-ferrous 240 480 3200  
  5,00 0,75 Ferrous 320 640 4500  
U25 8,00 1,25 Non-ferrous 350 700 5300  
  8,00 1,25 Ferrous 350 700 5300  
U38 12,50 1,50 Non-ferrous 550 1100 8300  
  12,50 1,50 Ferrous 550 1100 8300  
U50 15,00 2,00 Non-ferrous 660 1300 10000  
  15,00 2,00 Ferrous 660 1300 10000  
application example

Vibration Stealth Ships

Stealth ships - Ultra precision probes were implemented under water to detect vibration and/or motion of moving surfaces on sea-going vessels (propellers, rudders...). The combination of high bandwidth and extreme precision offered by the ECL101 was perfect for the challenge.

Info

The ECW110 provides wireless precision measuring technology with up to 42hrs continuous measurement. For applications where cabling is an issue such as robotics; measurement systems attached to a moving stage or moveable pallet; or where space is of a premium and multiple sensors are essential. The system communicates with a laptop using a dedicated Wi-Fi network at speeds up to 1KHz. The system consists of a driver and 1 to 3 probes.

Probe choices
Probe model Range mm Material Type

Resolution nm @1 kHz

 
U8 0,35 - 2,35 Non-ferrous 100  
  0,35 - 2,35 Ferrous 125  
U12 0,60 - 4,10 Non-ferrous 160  
  0,60 - 4,10 Ferrous 200  
Probe brochure
Application example

 

Maglev

Magnetic Levitation Stage - A contactless, wireless solution was developed for in vacuo real time control of the short stroke of a magnetically levitated precision stage. A set of synchronised probes were used to measure the z height and two rotations out of plane. 2kHz bandwidths were achieved with deterministic data transmission at latency figures of 300us; sufficient for real time positioning control. Packet loss rates of 1.1e-7 were also realised to ensure reliability.

Info

For demanding applications where a highly cost effective solution is required, the ECA101 system can deliver the precision you need. This non-linear system offers easy opeation with adjustable gain, offset and set-point switch output.

Probe choices
Probe model Range mm Near gap mm  
U3 0,50 0,05  
U5 1,25 0,25  
U8 2,00 0,35  
U12 3,50 0,60  
U18 5,00 0,75  
U25 8,00 1,25  
U38 12,50 1,50  
U50 15,00 2,00  
Probe brochure
application example

Thread measurement

Thread detection - While conventional sensors have trouble detecting the presence of threads, the ECA101 can easily detect the difference between a tapped and untapped hole. With an unthreaded hole, the signal is altered, with comparison to a threaded hole. As a distance sensor, thread pitch can be detected.

Info

The ECA110 is a versatile system ideal for applications requiring high resolution and high repeatability without the higher price of linear sensors. These embeddable PCB units are shipped from the factory fully calibrated with no user adjustments – ready to install. Suitable for embedded OEM applications, this system is vaialable in units of 100 or more.

Probe choices
Probe model Range mm Offset mm  
U3 0,50 0,05  
U5 1,25 0,25  
U8 2,00 0,35  
U12 3,50 0,60  
U18 5,00 0,75  
U25 8,00 1,25  
U38 12,50 1,50  
U50 15,00 2,00  
Probe brochure
02.3 Inductive systems application

How does inductive measuring work?

The primary functional piece of an eddy-current probe is the sensing coil. Alternating current is passed through the coil which creates an alternating magnetic field; this field is used to sense the distance to the target.

Eddy-current sensors use magnetic fields that completely surround the end of the probe. This creates a comparatively large sensing field resulting in a spot size approximately three times the probe’s sensing coil diameter.

For eddy-current sensors, the ratio of the sensing range to the sensing coil diameter is 1:3. This means that for every unit of range, the coil diameter must be three times larger. Thus a 5mm eddy-current sensor requires a 15mm target diameter. If your target must be smaller than the sensor’s spot size, special calibration may be able to compensate for the inherent measurement errors.

In some applications, the gap between the sensor and target can become contaminated by dust, liquids such as coolant, and other materials which are not part of the intended measurement. Unlike capacitive sensors, eddy-current sensors are not affected by non-conductive contaminants such as dust, water, and oil. Eddy-current probes are rated at IP67 and can even be used completely immersed in non-corrosive liquid.

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