Why S-type load cells are so popular, and why they may or may not be the best force transducer for your application.
People choose the S type design for some of the following reasons:
- It’s economical (typically less than $300 for capacities up to 2,500 pounds)
- Easy to mount (single threaded hole on the top and bottom of the load cell)
- Highly accurate (typically ±0.025% non-linearity)
- Universal (can be used in tension or compression)
What the S-Type Load Cell is Good for
Well controlled tension measurements, and in some cases it can be used in both tension and compression if the load is very well controlled, not allowing for any off center or off axis forces. If you are building or retrofitting a tensile testing machine to pull samples to destruction or just proof testing, this load cell design is perfect.
Another example could be suspending a hopper in a factory with the need to weigh the contents, the S-type design is ideal for this, typically 3 or 4 load cells (with tension vessel weighing mounting assemblies installed to allow for slight misalignments) are used to suspend the hopper.
When not to use the S-Type Load Cell
When weighing an object that can sway or rotate, The S-type load cell is generally used with eye-bolts or rod-ends when used in tension and this can cause binding or the associated hardware to unthread.
Or when the load cell will be used in both tension and compression and accuracy in compression is critical. The rated non-linearity (typically 0,025% of capacity) is only guaranteed when used in tension from most manufacturers, it is common for the compression results to be 2x out of the published specification. In this case we’d recommend a shear web type of load cell.
S-Type Load Cell Conclusion
This design has been around for ages, it is a proven form factor for many applications. Our customers have used it in various applications such as consumers building their own archery bow pull testing rig to NASA weighing objects being packaged for space travel.
As always we recommend contacting us with your applications details so we can aid in the decision process of choosing the correct load cell for the job.