Displacement Sensing the Baumer Electric Way

In the beginning, non-contact sensors were largely an on-off affair. They, like their switch predecessors either "saw" something or didn't. They passed this information on to a transistor or relay output, that is, an on or off signal. That worked pretty well. And, in most cases, it still works. But, advances in automated equipment lead to advances in sensors. Design engineers began to need information beyond simple presence and absence. Specifically, they needed to measure thickness, coplanarity, stack height and other qualitative values while retaining the benefits of noncontact sensing. In response, some sensor manufacturers developed sensors capable of providing a distance proportional analog output. In short, they developed distance sensors. Known collectively as displacement sensors, analog output sensors, linear sensors or distance sensors; they allow a user the benefit of gaining more than simple presence/absence while enjoying the simplicity of sensor integration. Before we break into the various technologies available for displacement sensors, there are some specific definitions pertaining to sensor performance that must be clarified.