Post on 30-Mar-2015
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