Cable Extension Transducers

Cale Ash

CEE 398KUC

Measurement Problem

Need to measure linear distances/displacements:

LVDT CETLinear Variable Differential Transformers Cable Extension Transducers

Two Options:

RangeUp To 12 in.

~$600 (12in.)

Flexible cable, but has

more moving parts

Rod can bend, but

fewer moving parts

~$400 (60in.)

Up To 1700 in.

Cost

Durability

Types

Cable Extension Transducers (CETs) Come In:

•Industrial Grade

•Laboratory Grade (Discussed here)

As well as in various sizes:

1.5” 3.5” 12”

Applications

Cable Extension Transducers (CET):

•Measure Linear Position

•Indicate Velocity and Acceleration

•Provide Reliability and Serviceability

• >105 cycle life

•Cable user-serviceable

Superior Performance

CETs are ideal in many instances:

•Where Perfect Alignment is Not Possible

•Cannot use LVDT Here!

•Where Large Displacements are Expected

•Up to 100” for Laboratory Models

•Up to 1750” (145ft.!) for Industrial Models

Superior Performance

CETs are ideal in many instances (cont.):

•If Difficult Mounting Conditions are Encountered

•Pulleys Enable Additional Flexibility

•Rigid Support Far From Measuring Point

Technology

Cable is wound around a precision machined spool attached to either a:

•Potentiometer (variable resistor, analog)

•Incremental Encoder (optical, digital)

A spring provides controlled recoil of the cable.

X-Ray Vision!

Instrumentation

Measurement Options Include:

Voltage

Divider

Unregulated

Input

Incremental

Encoder

Current

Output

NSEL Models

Models Used In NSEL

Both models feature:

•Adjustable Zero & Voltage Output

•High Accuracy (+/- 0.25%)

•Multiple Extension Ranges:

•PT1DC 0-2in. to 0-50in.

•PT510 0-2in. to 0-100in.

PT510

PT1DC

Availability

LVDT CET

Summary

•CETs provide a useful, sometimes superior, alternative to LVDTs.

•Rotary potentiometer provides long life and simple output

•CETs are also cost effective and easy to install

References

www.celesco.com CET Manufacturer

http://cee.ce.uiuc.edu/nsel/Facility/

For instrument availability