Comparison Of Non-Contact Displacement Sensors
Micro-Epsilon has compared four types of non-contact displacement measurement technology, advising on the pros and cons of each. The four main types of sensors are eddy current, laser triangulation, capacitive and confocal. The eddy-current measurement principle is an inductive measuring method. A coil is supplied with an alternating current, which causes a magnetic field to form around the coil. If an electrically conducting object is placed in this magnetic field, eddy currents are induced, which form an electromagnetic field according to Faraday's Induction Law. The controller calculates the change in energy transferred from the sensor coil to the target material and converts this into a displacement measurement. This method can be used on all electrically conductive, ferromagnetic and non-ferromagnetic metals. The size of the sensor is relatively small compared with other technologies and the temperature range is high due to the resistance measurement of the sensor and cabl...