Technical Blog

Load Cell Accuracy

Load cells are a type of sensor used within scales and other devices to measure force or weight.  They can operate under adverse conditions often have a protection rating from IP64 to IP69K.

Load cells are highly accurate devices but have different accuracy classes, these classes can give more information on precisely how accurate the load cell is which in turn can help with selection for certain applications.

Load Cell Accuracy

D1 – C2 – this load cell accuracy class is relatively low. It is sufficient for applications in simple building materials scales which are used to weigh cement, sand or water as well as non-trade applications.

C3 (0.0230%) – accuracy class C3 is the most common found in machine construction. Typical applications include; belt scales, platform scales and other electronic weighing devices. Of the load cells we provide, C3 is the most common accuracy class.

C4 – C5 (0.0174% - 0.0140%) - this accuracy class is higher and used for scales used for shop counter scales, filling machines, dynamic check weighing as well as platform and belt scales which require higher accuracy.

C6 (0.0116%) – C6 load cell accuracy class offer a very high level of accuracy, they are used for high precision check weighing and vehicle testing

OIML – OIML approval ensures the load cell is suitable and “legal for trade” meaning that they conform to a common agreed set f requirements. To gain OIML approval the load cell must gain an R60 certification.

Load cell accuracy classes continue into the As and Bs although these classes are not within our portfolio.

Factors Affecting Load Cell Accuracy

When selecting a load cell it is important to also consider factors which may affect load cell accuracy, some of these are;

Temperature - extreme temperatures can affect load cell accuracy and therefore the performance of the load cell. It is best to understand the temperature range of the environment of your application and check this against the “operating temperature” on the load cell datasheet before purchasing. 

Humidity – over time humidity can also have an effect on load cell accuracy although, this effect is not as dramatic as the effect of temperature. If your application is in a humid environment it is important to check that the load cell is designed for this. If your load cell is going to be functioning in a high humidity environment, IP protection of at least IP51, IP61 etc. will be required depending on the protection required from solids. All of our load cells have a higher protection rating than this, starting at IP64.  

Side and eccentric loads – if the load cell is exposed to pressure and weight from different angles or off centre, over time this can decrease the accuracy of the load cell. If your application specifically requires a load cell to continuously accept off-centre loads then this will affect which load cells are available. Single point load cells can accept off-centre loads so these are often a good choice for this type of application.

Mounting – similarly to the side and eccentric load issue, the mounting angle and location can affect the weight distribution of the load cell and therefore affect accuracy. We can provide a range of mounting equipment to help combat this.

Creep – creep is a change in load cell accuracy which can happen over time and repetitive use. Creep can affect the load cell itself or if other components are also under pressure, they can become deformed over time which can then affect the load cell itself. It is important to calibrate load cells regularly to help overcome this.

Load Cells from Variohm

We have been supplying load cells into various industries for many years and have a vast portfolio.

Load cells are available in different shapes and designs, some of the more popular load cell types are;

For more information on load cells, load cell accuracy or to discuss your application please contact us.

Article published on: 20/07/2020