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Cable Extension Transducer Applications

A cable extension transducer is a type of position sensor and is part of our range here at Positek.

Cable extension transducers are known by different names, these include; draw-wire sensor, string pot, yo-yo pot or string encoders.


Cable extension transducers use a spring-loaded spool and a retractable cable to measure position. This is an alternative way of measuring linear displacement than a more common linear position sensor. The spool and cable enable the cable extension transducer to measure large displacements whilst only requiring a small amount of space.

Cable Extension Transducer Applications

Cable Extension Transducers are used throughout a range of industries for various displacement measuring applications, for example;


  • Hoists
  • Telescopic ram
  • Hydraulic cylinder positioning
  • Materials handling
  • Platform levelling
  • Crane control
  • Agricultural equipment
  • Outdoor/ off-road construction equipment
  • Industrial equipment


Our sister company Variohm Eurosensor has been supplying cable extension transducers for a number of years, some more specific applications they have helped to solve include;


Lifting bridges and ramps - moveable bridges which rise to let boats pass through or ramps which need to rise and lower, these have used cable extension transducers to control this movement. They offer safe and reliable movement and can be very precise measuring the exact position the bridge or ramp is required to be in. Cable extension transducers can measure large distances, some over 10m, this makes them well suited to these types of applications.

Flight simulation - flight simulation is often used during training for pilots, cable extension transducers are used to enhance the flying experience. They can be highly sensitive and ensure accurate measurement and movement which is why they are well suited to this application.

Container Transportation - For Vehicles whose primary purpose is to transport industrial containers, cable extension transducers are used within the lifting system. The cable extension transducer offers precise and reliable measurement during the lifting and positioning process of the container.

Benefits of using a Cable Extension transducer

The main benefit of using a cable extension transducer is their compact size. Unlike a linear transducer which is a solid length extending a solid rod, a cable extension transducer's measuring cable is wound round an internal spool and extends out for measuring and is then retracted. Other benefits include:


  • Compact
  • High accuracy
  • Highly reliable
  • Suitable for indoor and outdoor use
  • Variety of outputs available (see product pages for options)
  • Cover large measuring ranges


Types of Cable Extension Transducers


There are different types of cable extension transducers with various aspects making them suitable for particular industries and applications.

Miniature Cable Extension Transducers are designed for motorsport applications, some of these are smaller than a human thumbprint but still function with high accuracy and reliability.

Hazardous Area Cable Extension Transducers are available with certifications making them suitable for intrinsically safe environments. These are extremely durable sensors to ensure they are robust enough for these environments.

Light Industrial Cable Extension Transducers are suitable for indoor applications with quick installation.

Plastic Housed Cable Extension Transducers include many of our small to mid-sized cable extension transducers suitable for many different applications. They offer easy installation and are highly compatible making them a popular choice.


Cable Extension Transducers from Positek


Our Cable ExtensionTransducers are robust and offer excellent accuracy. They are easy to use and don't require precise alignment to be able to function and give precise results.

Many series have different output options available, more details on outputs can be found on individual product pages.

If you need help selecting your cable extension transducer or would like to discuss your application please contact us.

Article published on: 21/05/2020

Article last updated on: 21/05/2020