Micro-Epsilon UK Ltd. - PRODUCT NEWS

New capacitive sensor with flexible probe enables gap width measurement in difficult-to-access areas

Micro-Epsilon has launched a new high accuracy, non-contact capacitive displacement sensor for measuring gap widths in difficult-to-access areas or objects. The probe can be manipulated and bent around obstacles in order to measure gap widths.

With the new capaNCDT CSG sensor, electrodes are applied to the top front and back of a 20cm-long printed circuit board substrate. Using the sensor electrodes and the differential calculation method, the width of a gap can be determined very accurately whilst moving the sensor into the gap.

The capaNCDT CSG has a special flexible probe that enables the sensor to be used in applications where the measurement target or object is difficult to access. The sensor is capable of measuring gap widths of 0.9mm up to 4.9mm at a resolution of up to 90nm. However, the sensor requires a metal measurement target and a relatively clean measurement gap.

In addition to its new CSG sensor, Micro-Epsilon has developed a similar version of the sensor that offers larger measuring ranges. The new capaNCDT CSE sensor has the same dimensions as the CSG but provides up to 2.5 times larger measuring ranges. This is achieved by equipping the sensor with a shielded electrode that is set back from the probe, which means for similar measuring range, the CSE sensor dimensions are significantly smaller.

For the same measuring range, the capaNCDT CSE sensor therefore provides considerable benefits to the customer. The cylindrical design of the CSE sensor and a connector on the back of the unit offer users high flexibility in terms of potential applications. The sensors can also be connected to any other Micro-Epsilon controller or electronics, which means sensor interchangeability is guaranteed.

Chris Jones, Managing Director at Micro-Epsilon UK Ltd commented: “Measuring gap width or the distance from one object to another at a certain depth are very common requirements in many industries. Conventional measuring methods are often unsuitable here, as they only record the gap at the surface and not at depth. The new capaNCDT CSG and CSE sensors are specifically designed to measure gap widths at depth in difficult-to-access areas using a flexible probe and compact, slimline sensor design.”

Multi-channel, sub-nanometre measurements
For applications that require sub-nanometre resolution and multi-channel measurements, the CSG and CSE sensors can be used in conjunction with Micro-Epsilon’s non-contact, capacitive measurement system, the capaNCDT 6500. This system offers sub-nanometre resolution, unmatched temperature stability and rapid changeover of sensors without any re-calibration required.

The capaNCDT 6500 Series is available as a benchtop or 19-inch rack-mounted unit. Modular in design, the system can accept up to eight measuring channels to suit individual customer requirements. Due to its extreme resolution and flexibility, the system is ideal for high-accuracy R&D applications, test laboratories, quality assurance, academic institutions and also semiconductor manufacturing, military, aerospace and defence applications.

The capaNCDT 6500 uses a unique, active-driven, hermetically sealed, triaxial RF cable, in combination with an active guarded three-electrode sensor. The system is therefore electron leakage-proof, creating a protected and homogenous measurement field. This means the user obtains stable, precise, interference-free measurement data.

The Capacitive Principle Explained
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.

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. Additionally 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.

With more than 35 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.

For sales and technical information contact:-

Chris Jones
Micro-Epsilon UK Ltd.
Telephone: +44(0)151 355 6070
Fax: +44(0)151 355 6075

April 2012

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