RF Speed Sensors

RF speed sensors 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 their VR counterparts, an RF speed sensor is not a passive device and requires coupling with a signal conditioners/preamplifier. These devices produce a digital square wave output versus the analog sine wave of the VR speed sensor.

Standard »

Standard versions have open fronts and are epoxy encapsulated. Models are also available with closed fronts as well as hermetically sealed versions for applications that require protection from moisture and other fluids.

High Temperature »

RF Sensors with a temperature range up to 750°F.

Amplified (Active) »

Amplified sensors integrate a preamplifier within the sensor housing and offer excellent noise immunity and greater transmission capability. Sensors offer near-zero velocity (2 Hz) speed sensing, large air gap capability, and several digital output choices.

Intrinsically Safe
ATEX, IECEx, & CSA »

MSI intrinsically safe sensors are certified for use in both North America (CSA with NRTL/C) and Europe (ATEX compliant with 2014/34/EU) to the most stringent requirements.

Principles of Operation

Advantages of Motion Sensors (MSI) RF sensors are: near zero speed response, no magnetic drag, large air gaps and the ability to sense non-ferrous metals like aluminum and nonmagnetic stainless steel, as well as ferrous metals. RF sensors use a modulated carrier signal to sense rotating metals. Unlike their Variable Reluctance (VR) counterparts, RF sensors require an internal or external preamplifier/signal conditioner to operate. When a target is sensed, eddy currents are formed which decrease the signal amplitude. The preamplifier/signal conditioner demodulates the signal, detects the voltage drop-offs and produces a square pulse wave (digital) output with a frequency directly proportional to the number of turbine blades, gear teeth, etc. that have been sensed.

ATEX & IECEx Certified: Custom & Standard Speed Sensors for Intrinsically Safe applications (also approved by CSA w/NRTL/C)