Understanding Weighing Cell Technology

Understanding Weighing Cell Technology

In today’s industry, two weighing cell technologies are predominately used.  They are strain gauge and electromagnetic force compensation (MonoBloc) technology.  MonoBloc weighing technology ensures the highest level of counting accuracy and repeatability for reliable results. Generally, MonoBloc load cells are ten times more accurate than standard load cells with strain gauges.

Precision, Ruggedness, and the Right Fit

Modern-day weighing cells need to have three characteristics in common in order to be useful and optimal: precision, ruggedness, and suitability.

Precision is important because volumes of money can be lost over the lifespan of a scale system if accuracy isn’t up to snuff. Most industries adhere to the strictest of requirements. Therefore, failing to meet these standards of precision results in inefficiencies will cost a business.

Ruggedness is also important, given the often fast-paced nature of production environments.

Finally, each scale system has to be the right fit. No two situations are exactly the same, not even within the same industry. It’s imperative that an organization find weighing cells that fit their requirements, and can be adapted to that particular deployment.

Different Technologies Used in Weighing Cells

The process for selecting a particular weighing cell should be based on the level and degree of precision required for that particular application, as well as the operating environment.

Technologies have been developed to help engineer weighing cells that fit different environments and conditions. After all, there are very diverse and strict requirements for weighing cells, so it makes sense that technologies have been evolved to handle all kinds of situations.

With wire strain gauge technology, a metallic or semiconductor material of small cross sectional area is bonded to a surface and elongates or contracts with that surface. This deformation results in a change in its electrical resistance, providing means for subsequent measurement. Strain gauge technology is:

  • Diverse
  • Rugged and robust
  • Integrated easily
  • Economical with acceptable accuracy
  • Easily connected to terminals due to analog interface

Downsides include limited resolution and limited accuracy. Thus, strain gauge technology isn’t useful for all situations.

There is also electro-magnetic force compensation technology (MonoBloc).  With this principle, the loaded weight is compensated by an electro magnetically generated force. A compensation coil through which a permanent current flows is inserted in a permanent magnetic field. In the unloaded condition, current regulation ensures that the system is in the zero position. With the aid of an opt electronic position sensor, the coil position is controlled to an accuracy better than a thousandth of a millimeter. It records vertical positional changes when the scale is loaded. This information from the controller is used to generate a compensation current in the coil that returns the weighing system to zero. The current is directly proportional to the loaded weight. Its value is digitalized and sent to the display. Electro-magnetic force compensation (MonoBloc) offers:

  • High precision
  • High accuracy
  • Internal calibration
  • Digital communication

Both electro-magnetic force restoration and strain gauge technology are useful in their own ways. Finding the right technology and weighing cell is a function of understanding your requirements and then fitting them to a cell with the appropriate specifications.

Contact Acme Scales for more information on weighing cells and obtaining the right cells for your operation.