Vorrichtung zum Überwachen einer entlang eines vorgegebenen Weges bewegbaren Einrichtung sowie Modulatoreinheit und Auswerteeinheit für diese Vorrichtung

摘要

The apparatus (10) has at least one sensor unit (16) fastened to the movable device (12) for detecting obstacles in the path of the moving device (12). A modulator unit (44) is fastened to the movable device (12). The modulator unit modulates a carrier signal (PS) with a predetermined sensor signal of the sensor unit (16). The apparatus also has an electric coupling device for electrically coupling the modulator unit to an analyser (46). On detecting modulation at its input the analyser (46) generates a first monitoring signal for monitoring the movable device (12). A signal generator (38) for generating the carrier signal (PS) is contained in the modulator unit (44) or is connected to the coupling device on the side of the analyser. The modulator unit (44) is constructed such that the carrier signal is not modulated when the sensor signal deviates from a predetermined sensor signal. The analyser (46) generates a second monitor signal different from the first on detection of the unmodulated carrier signal (PS).