Load cell creep is perfectly natural in load cells. It is the change of the cell’s output in real-time while it is weighing an object. This happens under constant load conditions and assuming the time period is long. These refer to when a weight does not change during a period of time. If the weight is not changing, then the creep refers to other factors causing the measurements to be inconsistent, which in turn affects the load cell’s output. Ideally, environmental conditions will remain constant.
What Causes Load Cell Creep?
The creep happens when a deformation needs time to resume its original shape. Generally, a load cell measures mass when the force applied to it causes a deformation to the strain gauge. The amount of resistance that the strain gauge generates is converted to an electric signal, which denotes a unit of measurement. Before the gauge reaches that final shape, there may be fluctuations. This would be the creep.
Creep is measured in intervals, because the changes in it occur over time. Creep recovery refers to the change in output that occurs over time after the load is removed from the cell, which takes away the force in turn. Usually the operator specifies a time interval for this part. The strain gauge is taking time to return to its original form and deliver a consistent output.
Load cell creep recovery refers to the difference between the signal after the load is removed and the signal when the load is applied. This is usually a percentage of an applied load over time, which is done in intervals. If you can’t do constant weight or mass, load cell creep recovery can be measured with a weight close to the carrying capacity.
Creep is more important when objects remain on a load cell for a long period of time. This happens with bulk storage, such as with grains in farming. If an object is only on a scale for a few minutes, then the creep is less important. Its change has more impact when the object spends a long time on the sale and cannot be moved immediately.
Generally, objects increase and decrease in mass on a micron scale when being weighed if there are changes in temperature. This can happen in environments with rapid changes, especially in humidity. The idea of constant weight is that the temperature variances don’t happen, which means the mass isn’t affected.
How To Improve Load Cell Signals
First, implement strategies to ensure that environmental conditions remain constant. Record temperatures and see if they can be kept the same. Reducing potential static electricity by grounding your load cells and having a system for getting rid of the discharge.
The more mass that an object has while being weighed, the larger amount of creep ensues. This is because a heavier load affects the strain gauge significantly. You want to reduce the amount of creep that will naturally occur. That can happen with some artful arrangement.
Ideally, you want load cells that can reposition their strain gauges with as little creep as possible. Some are designed for this efficiency so that the deformation after a force is applied to the strain gauge is corrected quickly, allowing the load cell to return to a 0 default. You also don’t want to have to check for this on a regular basis during a daily operation; scheduled maintenance would be more efficient in the long run.
You also want strain gauges where the connectors are solid and rugged. If the connectors remain stable, then it reduces the likelihood of creep and will maintain an accurate signal to convey from the strain gauge to the display.
Use two strain gauges to test for creep within a load cell. Test them to see which one is more suited for your operation, since different strain gauges experience creep in different directions. This is best seen in action but before you engage in daily operations.
In some cases, we recommend implementing load cells with each having a creep that goes in the opposite direction. This allows the two reactions to cancel each other out and provide a more accurate result.
Reduce Your Combined Error With Arlyn Scales
Arlyn Scales keeps working to improve load cells and strain gauges. We revolutionize standard weighing systems so that they can handle heavier loads while still delivering on precision and accuracy. Our strain gauges are designed to reduce damage from extra weight, and to maintain consistent electrical signals. We always strive to improve upon established models to deliver more to our customers with heightened sensitivity.
Talk to one of our representatives about scales and load cell options. We want to help you learn how to handle applied loads and the potential inaccuracies in measurements. Ask about our customization options and what they can do to add efficiency to your industrial weighing processes.
