Vehicle sensor monitoring system

摘要

In a system for controlling the horizontal and vertical alignment of a materials handling vehicle and for transferring articles to and from storage locations of a warehousing system in which several control sensors are positioned on the materials handling vehicle, a monitoring method and circuit for determing the operational status of the sensors by monitoring their status during a selected portion of a cycle of operation when their output is known. In one embodiment sensor outputs are cross checked against each other during a portion of an operating cycle in which the sensors outputs will be at a predetermined relationship to one another.