Contrast sensors are high-resolution light sensors that differentiate objects according to their gray values. The robust contrast sensors from Balluff detect even small contrast differences, have a high switching frequency of up to 30 kHz and are therefore particularly fast. They enable high positioning accuracy and are therefore suitable for a wide range of applications, for example in the printing and packaging industries. Series=21M, Dimensions=12 x 50 x 42.5 mm, Interface=PNP normally open/closed (NO/NC), Input function=Key lock on/off, Teach contrast (switching point), Functional principle=Contrast button, Functional principle optical=Light button, focused, Optical feature=Coaxial optics, Beam characteristic=Focused, Light type=White light, Light spot size=Ø 3.5 mm at 19 mm, Range=17...21 mm, Connection=Connector, M12x1 plug, 4-pin, Housing material=Zinc, die-cast aluminum, Active surface, Material=Glass, Operating voltage Ub=10...30 VDC, Approval/Conformity=cULusCEEACWEEE