Choosing an LVDT

This page provides information and guidance to help you when choosing an LVDT for your application.

1. Ease Of Installation
Our range of LVDT displacement transducers are available with a variety of body fittings and core assemblies.  These include:-

  • Axial or radial cable exit
  • Core only
  • Plain core with extension rod
  • Guided core with extension rod
  • Sprung loaded core with extension rod
  • Guided core with extension and rod end bearings

2. Material
Most of our LVDT displacement transducers are constructed in stainless steel.  For special applications, other materials can be used on request.

3. Sealing
Some models offer standard sealing to IP65, but other ratings are available up to IP68 for full submersible use. Our custom-design service allows variations in the sealing of all models. Please consult our Sales Office.

4. Robust Construction
We offer different levels of construction to suit the application.  The industrial series give a high level of protection for harsh industrial conditions, however, for projects which involve possible extreme mistreatment, we recommend use of the heavy industrial series.

5. Electrical Connection
The choice of standard connections include:-

  • Flying cable (standard length is 2 metres – longer lengths to order.)  Types available – PVC, PTFE, Polyurethane and armoured cables.
  • Connectors:  Hirschmann and Military, others on request.

6. Measuring Range
Each series of model types offers a wide choice of measuring ranges.  The range can be applied as a bidirectional measurement about the zero point i.e. ±5.0mm, as a unidirectional measurement i.e. a ±5.0mm becomes 0-10mm, or for improved linearity performance part of the full range may be used.

7. Linearity
Our definition of linearity is that the output curve over the quoted linear range will not deviate from a theoretical straight line drawn through zero by more than 0.5% of full stroke.  Linearity can be improved by using a smaller part of the total measuring range.

8. Outputs
The standard LVDT displacement transducer provides an A.C. output and need a supporting electronic unit to energise and condition the signal.  Some models are available with internal electronic circuitry to give a DC in – DC out performance. A suitable DC supply is needed and the choice of outputs available are ±2.5Vdc bipolar, 0-5Vdc, 0-10Vdc and 4-20mA.

9. Other Specifications To Be Considered:-

  • Temperature range.  The standard range is -30°C to +85°C, while high temperature versaion are rated from -30°C to +150°C.  For higher temperature ranges, please consult our Sales Engineers.
  • Frequency response.  This is determined by the mechanical arrangement used, the frequency of the energising supply and the filtering characteristics of the conditioning system.
  • Weight.  The mass of transducer, in particular the core assembly, can be important in some applications.