Download Capacitive measurement explained

20th June 2014
Ref. ME218
New single channel capacitive controller is compact, robust and cost-effective
Precision sensor manufacturer Micro-Epsilon has launched a new compact, robust
capacitive displacement controller that provides a combination of technical advantages
and high performance at an affordable price.
The new capaNCDT 6110 controller is suitable for measuring displacement, distance and
position in a diverse range of applications, from test cells to on-vehicle testing, mobile
applications and highly automated production environments. In addition, due to its low
cost, compact design and high performance, the controller is particularly suitable for high
volume OEM applications. Here, the capaNCDT 6110 can be used as a base specification
for modification to user-specific requirements.
Robust and simple to use, the capaNCDT 6110 is compatible with all capaNCDT series
capacitive sensors from Micro-Epsilon. The measurement system comprises a capacitive
displacement sensor, sensor cable, controller (electronics) and a supply/signal output
cable. With all items available from stock, the user can quickly select the most suitable
sensor range and cable length to be used with the capaNCDT 6110 electronics. The
system offers high temperature stability (200ppm), maximum linearity of 0.1µm and
maximum resolution of 0.005µm. Measurement output values are selectable 0-10V or +/5V DC. Seven measuring ranges are available from 0.2mm up to 10mm.
Chris Jones, Managing Director at Micro-Epsilon UK comments: “Due to its compact,
robust design and flexible 24V [9-36V] DC power supply, the capaNCDT 6110 is ideal for
mobile applications, on-vehicle (passenger cars and trucks) applications, as well as
integration in industrial plant and machines. The measurement system is suitable for use
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with all electrically conductive materials and offers nanometre repeatability and high
temperature stability.”
Capacitive measurement explained
Capacitive displacement measurement is one of the highest precision methods of noncontact displacement measurement. With the capacitive principle, sensor and target
operate like an ideal parallel plate capacitor. The two plate electrodes are formed by the
sensor and the opposing target. If an AC current with constant frequency flows through the
sensor capacitor, the amplitude of the AC voltage on the sensor is proportional to the
distance between the capacitor electrodes. An adjustable compensating voltage is
simultaneously generated in the amplifier electronics. After demodulation of both AC
voltages, the difference is amplified and output as an analogue signal.
Because the sensor is constructed like a guard ring capacitor, almost ideal linearity and
resolution against metal targets is achieved. The technology also offers high temperature
stability, as changes in the conductivity of the target have no effect on the measurement.
Capacitive sensors can also measure insulators.
The technology is sensitive to changes in the dielectric sensor gap and so operates most
effectively in clean, dry applications. Cable length is also relatively short due to the effect
of cable capacitance on the oscillating circuit tuning.
Typical applications for capacitive displacement sensors can be found in automation
systems, semiconductor production, mechanical engineering, medical devices, clean
rooms, ultra-high vacuum (UHV) conditions, test cells and any application where high
precision, stable measurements are required.
Rapid sensor replacement
The capacitive measuring principle enables the rapid replacement of a sensor in just a few
seconds. This simplified replacement of sensors with different measuring ranges and the
interchangeability of capaNCDT controllers can be carried out without any re-calibration
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required. A typical sensor replacement takes around 5 seconds, unlike conventional
systems that have to be subjected to time-consuming calibration and linearisation.
For more information on the capaNCDT 6110, please call the Micro-Epsilon sales
department on 0151 355 6070 or email [email protected]
– ENDS – [563 words]
Note to Editors: Micro-Epsilon (www.micro-epsilon.co.uk) is a major global manufacturer of sensors,
headquartered in Germany. The company’s range of displacement sensors measure everything from to distance,
position, vibration, dimensions and thickness, using both contact and non-contact measurement techniques.
These techniques include 1D, 2D and even 3D laser-optical sensors and systems, eddy-current, capacitive,
LVDT & inductive, potentiometric and draw-wire principles. In addition, Micro Epsilon has developed its own
range of non-contact infrared temperature sensors that can measure virtually any target temperature from -40 to
+3,300°C. The company also manufactures a comprehensive range of colour recognition sensors.
With more than 45 years’ experience in the industry, Micro-Epsilon isn’t just a sensor manufacturer. The
company is highly innovative and understands the importance of providing complete solutions and support
services for its customers. The firm is renowned for its expertise in consulting, development and application of
industrial sensors to complex, customer-specific solutions for measurement, inspection and automation. The
focus is on selling technical advantage to its customers.
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Reader Enquiries/Advertising: Louise Dodd,
Marketing Executive,
Micro-Epsilon UK Ltd
1, Shorelines Building,
Shore Road
3
Birkenhead
Cheshire CH41 1AU
Tel: +44 (0) 151 355 6070
Fax: +44(0) 151 355 6075
Email: [email protected]
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