The simple noncontacting detection of position plays a major role in t
he automation technique. Especially for the application in production
plants, a high level of quality, reliability and durability is an abso
lute necessity. In this environment, the use of magnetic field sensors
for detecting the position of a permanent magnet is at first glance a
very well known and solved physical problem, but with respect to the
economic reality it places major demands on existing manufacturing tec
hnologies. In developing magnetic switches, one has to consider differ
ent interfaces in order to achieve the important aim to avoid undefine
d switching states under worst case assumptions and to minimize the ov
erall size of the sensor, including the electronics. (C) 1997 Elsevier
Science S.A.