Introduction to Load Cells

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A load cell is a force (pressure) sensor that uses strain gauges which are mounted in specific patterns to provide a meaningful value of the change in pressure or weight. In general, load cells may be used to measure:

  • tension
  • compression
  • shear

Common uses for load cells include:

  • mechanical testing
  • ongoing system monitoring
  • industrial scales and weighing

One common application of load cells in industrial applications is in a scale used to weigh product. e.g., the weight of material that is placed into a tank. The load cells must be large enough to be able to determine the weight of the tank plus the weight of the material in the tank.

Important specification parameters for load cells include:

  • force range -- the range of required linear output
  • load-measurement range -- the range of required linear output
  • accuracy

Load cells can be divided into two broad categories by type:

  • bending beam load cell: this type of load cell uses a principle of measuring force on a cantilever beam. It will have shear stress and bending stress along the cross-sectional area of the beam. The stress can be measured by strain gauges and converted into an equivalent amount of pressure.

  • shear beam load cell: this type load cell uses an I-beam design because the shear stress is uniform at the web of the beam. The shear beam load cell is more expensive but it does have advantages such as returning to zero more quickly than the bending beam when load is removed. It has a higher tolerance of dynamic forces and vibration, and it better sealed for environmental conditions such as the necessity of wash down in food processing.

Types of Load Cells:

  • Low Profile Load Cell
  • Load Button Load Cell
  • Through Hole Load Cell
  • Tension and Compression Load Cell
  • Miniature Load Cell
  • Donut Load Cell
  • Beam Load Cells

Sensors related to load cells:

  • Rotating and Reaction-Torque Sensors: shaft and flange configurations for a wide range of applications.

Load Cell and Torque Sensor Signal Conditioning:

  • Bench top or stand alone Amplifier / Conditioners
  • Panel-mount Load Cell displays
  • Portable Load Cell indicators

NEXT: Electrical Circuits for Load Cell Sensors