Capacitive sensor enables gap width measurement in difficult to access areas

With the capaNCDT CSG module, 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 accurately whilst moving the sensor into the gap. The device 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 0.9 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 2.5x 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. The cylindrical design of the CSE sensor and a connector on the back of the unit are said to offer users high flexibility in terms of potential applications. The sensors can also be connected to any other Micro-Epsilon controller or electronics, ensuring sensor interchangeability. Chris Jones, managing director at Micro-Epsilon UK said: "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."