All speed sensor types are available in models that are ATEX certified for intrinsic safety and in Custom versions developed to suit specific application and user requirements.
Hall Effect
This type of speed sensor provides zero speed sensing and is available in both oriented and non-oriented models. The target can be either ferrous, such as
a gear, sprocket, etc. or magnetic (discrete or multi-pole). Standard MSI Hall Effect sensors have unique safeguards built into
their circuits to prevent damage from incorrect hookup and can be obtained in models that produce the most popular digital
outputs.
Variable Reluctance (VR)
Speed sensor that can sense a ferrous metal target and is ideal for use in all types of environments and user specifications. Options include hermetically sealed, cryogenic, high temperature,
intrinsically safe and explosion proof. In addition to the more common VR sensors, MSI also offers an inductive type speed sensor for
applications where magnets, rather than ferrous metal, will be sensed.
RF (Eddy Current)
Offer low speed response, no drag, large air gaps and sensing characteristics which enable this type of speed sensor to sense non-ferrous metals like
aluminum or nonmagnetic stainless steel in addition to ferrous metal. Unlike the VR counterparts, an RF speed sensor is not a passive
device and requires coupling with a signal conditioners/preamplifiers. These devices produce a digital square wave output versus the
analog sine wave of the VR speed sensor.
Amplified (Active) Speed Sensor
Combines high sensitivity amplifiers and signal conditioners with either variable reluctance or RF transducers.
Unique features include near zero velocity (2 Hz) speed sensing, large air gap capability and several choices of pulse output.
Magnetoresistive (MR)
Similar to the Hall Effect speed sensor, MR sensors are highly sensitive devices that can detect very small changes in magnetic fields caused
by a passing target (ferrous or magnetic), and convert this into a digital output. Speed sensors versions are available for quadrature
(bi-directional) or single direction sensing.
