When selecting the best load cell for a specific application, engineers must consider multiple factors – including range, accuracy, linearity and hysteresis. The force specialists at WIKA USA also look at the application's environment and loading conditions, which can have a major impact on the overall performance of a load cell.
Miniature load cells, often referred to as strain gauges or straight bar load cells, are designed to translate weight (pressure or force) into an electrical signal by changing the length of a bonded foil strain gage when a load is applied. This results in a change in resistance which can then be converted into an output signal by using a built-in amplifier.
There are a wide variety of miniature load cells on the market, all with unique features to meet your specific needs. Some of the most popular include donut, beam and button style load cells.
There are several reasons for fluctuations in load cell readings – including physical damage, shock loading, long term overloading and environmental conditions. One way to check a load cell's input resistance is to use a digital multimeter set to ohms and test the positive and negative excitation wires to see how much their total resistance is (it should be equal). If you find that the resistance is not equal to the load cell datasheet's specification, it is likely due to one of these problems. Fortunately, these issues can be resolved by performing some simple maintenance.