Stroke-measuring cylinder rod for determining arm state or drive position e.g. of digger

摘要

The rod determines the position of a piston and rod with respect to a reference position. The rod (400) has a magnetic scale area (430) of depressions and ridges, which are equally spaced and are used by a magnetic sensor and associated processing equipment to calculate the rod position. One or more areas (410,420) are included where the spacing between ridges and depressions are not even. The uneven areas are arranged at known distances from each end of the scale area. The position determination device comprises a microprocessor, a magnetic sensor, a signal processor and a divider circuit.