NC-DVRT Non-Contact Displacement Sensors (0.5 ... 5 mm)
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Sub- and Microminiature Displacement Transducers by MicroStrain
Displacement Transducers by Kyowa
Miniature displacement sensors - DVRTs, include gauging, non-gauging (free sliding core) and non-contact displacement transducers.
The product line includes sub-miniature displacement sensors, micro-miniature displacement sensors, and miniature non-contact displacement sensors.
Non-contacting, continuous output inductive position sensors for harsh environments and tight spaces. Designed for both conductive and ferrous targets.
Description
Ideal for difficult sensing applications, this transducer can measure displacement & proximity of a metal target without physical contact. The measurement is unaffected by interposed nonmetallic, non-conductive materials, such as polymers and biomaterials.
The stainless shell of the device houses two coils; one for sensing and the other for temperature compensation. The coils and flex circuit leadouts are mounted on a stable PEEK substrate. This assembly is potted in a stainless housing using high grade, vacuum pumped epoxy.
This packaging allows the sensor to be used in applications requiring long term immersion in water and saline solutions.
Signal conditioners are provided in multichannel "plug and play" enclosures, including cables and UL approved power supply. Miniature circuit cards are also available for high volume OEM customers. The DVRT comes with an integral strain relieved, flex circuit and connector. As with all MicroStrain products, every device is carefully tested prior to shipment, and calibration data are included with each order.
How it works
Two coils within the non-contact DVRT's housing form its sensing and compensation elements. When the face of the transducer is brought in close proximity to a ferrous or highly conductive material, the reluctance of the sense coil is changed, while the compensation coil acts as a reference.
The coils are driven by a high frequency sinewave excitation, and their differential reluctance is measured using a sensitive demodulator. Differencing the two coils outputs provides a sensitive measure of the position signal, while cancelling out variations caused by temperature.
Ferrous targets change the sense coils' reluctance by altering the magnetic circuits permeability; conductive targets (such as aluminum) operate by the interaction of eddy currents induced in the target's skin with the field around the sense coil.
Applications
automotive, robotic systems
miniature control elements
medical biomaterials
tissue deformation, implant micromotion
materials science, civil engineering
structural deflections, strain extensometry
optical components
linear/angular positioning
miniature sensors
force, torque, acceleration
