It is critical to identify the physical size and material properties of the target to determine the sensing range required. Even though inductive sensors detect metal, the target must be large enough to disrupt the sensing field. The minimum target size is defined according to EN 60947-5-2 with a 1 mm thick square target with the length of each side equal to whichever is greater: The diameter of the circle inscribed on the active surface sensing face, or Three times the rated operating distance. The target material is important to identify since most metals are compounds and not pure. Technical data and specifications for inductive sensors are based on ferrous steel according to EN 60947-5-2. If the target material is stainless steel, aluminum, brass, or copper, a reduction factor will need to be applied to the sensing range (see, Sensing Range Derating Factor Chart here). The Sensing distance of inductive sensors typically ranges from 1 mm to 40 mm. Inductive sensors can detect both ferrous and non-ferrous metals, but not necessarily at the same sensing range. For example, a standard inductive sensor technical specification lists a 10 mm sensing range (this would be using a ferrous steel target). That same sensor would only have a range between 2.5 mm to 10 mm, depending on the composition of the metal.