The purpose of the belt misalignment switch is to give a warning or/and stop the belt conveyor when the belt has moved too much sideways (during the operation that the belt or the structures nearby could be damaged). The switch is normally used with the upper belt, but in unstable conditions in long conveyors, it can also be used with the return belt. The type of belt misalignment switch for normal applications is ES20, where the lever arm of the switch turns perpendicularly sideways. In applications where the conveyed material can go over the upper belt’s edge, it is recommended to use an ES21 type switch. In this type, the lever arm turns 45 degrees in relation to the belt.