National Physical Laboratory

Are there any general 'do's and don'ts' in force metrology? (FAQ - Force)

Yes there are - some are listed below:


  • Do make sure you understand the definitions of the specifications that are used by the manufacturers of the force measurement system you intend to use
  • Do make sure that the rated capacity of the force transducer is equal to or greater than the applied forces
  • Do consider the whole measuring range needed. What are the largest and smallest forces you expect to measure? If you do not know, a transducer with large measuring range and high overload is of benefit.
  • Do consider inclined forces and the resultant side forces (those perpendicular to the transducer's loading axis) present in the application and the capability of the force transducer to withstand them and measure to the required uncertainty in their presence. It does not mean that if a device has a specification that says it will withstand 100 % side force that this side force will not affect, to some degree, the measurement of the force acting along the principal axis.
  • Do consider the effect of dynamic forces in the application. The rating of the transducer must encompass these forces within its normal working range or some means of protecting the load cell must be designed in. A dynamic overload (one of very short duration) beyond the safe overload of the load cell will damage it just as surely as a static one.
  • Do consider the working environment that the transducer will be subject to, consider temperature, humidity, water splash, and potential mechanical abuse.
  • Do consider if any of the force to be measured is taken by force shunts such as supports, bearings, flexures, pipes etc. causing errors in the measurement
  • Do consider the mounting of the sensor. The quality of the measurement signal depends on the correct mounting of the sensor in the machine structure. Does the mounting minimise the impact on the machine construction?
  • Do consider how easy it is to calibrate and test the mounted sensor or the whole set-up. Although, correctly mounted, sensors may have a long lifetime, it is better to consider also how to dismount them later, as the sensor might be used again.
  • Do choose an appropriate data acquisition rate. Filtering and signal conditioning (e.g. amplifier settings, low/high pass filters, software) need to be set correctly.
  • Do, if you use a piezoelectric force sensor, put the amplifier into 'operate' either manually or triggered through switches before each measurement to give repeatable measurements.


  • Don't design or use a load cell where the applied forces (static or dynamic) normally encroach into the safe overload capacity of the transducer.
  • Don't lay connection cables alongside cables carrying power or large switching currents.
  • Don't lay cables where they can be damaged by fork-lift trucks or other vehicles operating in the vicinity.
  • Don't change the cable length if a transducer is supplied with one fitted - such changes may affect the system calibration.
  • Don't allow ingress of moisture or contamination to the connections either at the transducer, junction boxes or instrument.
  • Don't pick up a transducer by its cable, if it has one.
  • Don't forget to include purchase price, lifetime, installation, and calibration costs of transducer, amplifiers and the whole measuring chain when comparing costs.
  • Don't design an installation with multiple force paths unless they are all measured or the position of force application is well controlled.
Last Updated: 19 Apr 2011
Created: 8 Oct 2007


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