The MFS and MGS magnetic sensors
from ifm electronic comprise solidstate
magnetic sensing chip, as used in
hard drives, packaged in a sealed
stainless steel housing in standard M12
(MFS) and M18 (MGS). The housing is
formed from a stainless steel body and
an integral stainless steel sensing face.

This alternative position detection
technology is said to open up new
applications in harsh environments
that are too dirty for photocells. The
magnet and sensor also operate
through non-ferrous metals without
reduced sensing. ifm electronic says
iron and steel behind a magnet can
increase the strength of the magnetic
field (+20%), giving greater range.

Standard ranges depend on magnet
type and strength, but are typically
reckoned to be 60 to 70mm.