Sensor and evaluation system for end position and threshold value detection

摘要

The invention relates to a sensor and evaluation system for capturing data at a measuring station (3), in particular for use in double sensors for determining end positions and limit values. The individual sensors (1, 1', 2, 2', 16, 16') are operated as sensor pairs (1", 2", 16") by a largely shared control circuit consisting of two connecting lines (5, 6) with an electric current or voltage of alternate polarity. A state of a sensor (1, 1', 2, 2', 16. 16') is transmitted on the corresponding half-wave of the sensor current and evaluated by a switching amplifier (13) in relation to polarity and amplitude. Said sensor and evaluation system reduces the number of connecting lines required. In addition, interference from neighbouring sensors is largely excluded, so that sensors can be mounted more closely together in a system. Said sensor and evaluation system is especially suited for equipment required to comply with the DIN 19234 (NAMUR) standard.