10 Facts

1. The heart of every scale.

The load cell is the most important component of a scale system. Without a load cell, a scale cannot measure the change in force caused by the load, or in other words, the weight. The load cell is truly the heart of every scale.

2. Enduring origins.

Load cell technology dates back to 1843 when British physicist Charles Wheatstone created a bridge circuit to measure electrical resistance. He named this new piece of technology the Wheatstone bridge, which is still used as the basis for today’s load cell strain gauges.

3. Using resistance.

Strain gauges use the theory of resistance. A strain gauge consists of a very fine line of wire that is woven back and forth in a zig-zag grid to increase the effective length of the wire when force is applied to it. This wire has a certain amount of resistance. When load is applied, that wire either stretches or compresses, thus increasing or decreasing its electrical resistance—which we measure to determine weight.

4. Diverse measurement.

Load cells are capable of measuring more than just cantilever force, or the force caused to one end of the load cell. In fact, load cells can measure the electrical resistance from vertical compression, tension, and even suspended tension.

5. Three main groups.

Load cells are categorized into three main groups: Environmentally Protected (EP), Welded Seal (WS), and Hermetically Sealed (HS). Knowing which type of load cell you need will effectively match the load cell to your application, ensuring optimal results.

6. Importance of deflection.

Deflection is how far the load cell bends from its original resting position. Deflection is caused by force (the load) applied to the load cell and allows the strain gauge to do its job.

7. Load cell wiring.

The colors combination for load cell wiring excitation, signal, shield, and sense can be vast with each manufacturer developing their own wiring color combinations. You always need to refer to the original equipment manufacturer’s manual or the Rice Lake Wiring Guide to ensure you are reading your wires right.

8. Custom scale solutions.

You can integrate load cells into pre-existing structures such as hoppers, tanks, silos and other vessels to create a custom scale solution. These are great solutions for applications that require inventory management, recipe batching, material discharge, or prefer to integrate weighing into established processes.

9. Load cells and accuracy.

High-accuracy scale systems are generally considered to have system errors of ±0.25% or less; lower-accuracy systems will have system errors of ±.50% or greater. Since most weight indicators typically have an error of ±0.01%, the main source of scale error will be the load cells, and more importantly, the mechanical arrangement of the scale itself.

10. The right load cell for you.

The most effective way to construct a highly accurate scale system that works is to choose the right load cell for your application. It’s not always easy to know which load cell is best for each unique application; therefore, you should always consult with an engineer and a load cell expert.

Consult with us.

Learn more about load cells at Rice Lake’s Load Cell and Weigh Module Resource Center and consult with Rice Lake load cell experts whenever you need help choosing the correct load cell for your business.