Technical Library

C-LVDT Bandwidth - Response Speed

Capacitive Sensor TechNote LT03-0027

Copyright © 2013 Lion Precision. www.lionprecision.com

Summary

The speed at which the C-LVDT can respond to movements of the surface it is measuring is determined by the amount of displacement and the adjustment of the contact force. This TechNote provides maximum speeds/displacements for a variety of contact forces.

The calculations below are based on a 6.9 g moving mass of a C-LVDT (5.55 g Shaft, 1.35 g Tip). Shorter, older models ( no longer available) had lower mass and slightly higher response speeds.

C-LVDT Mechanics

c-lvdt mechanics cutaway

The C-LVDT uses air pressure to create a force that extends the contact point from the body of the device. This determines the contact force and is adjusted with a small valve.

Contact Point Speed

The contact force determines the maximum speed at which the target can move away from the probe a given distance and not lose contact.
The calculation requires three datapoints:

For Linear Motion

c-lvdt linear motion

For Rotary Motion

c-lvdt rotary motion calculation

 

C-LVDT Response Speed Chart

This graph charts the curves of maximum speed at which a target can move a given distance (in a sinusoidal pattern) and maintain contact with the contact point for reliable measurements.

c-lvdt response speed chart

 

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