Load Cell Testing Tips

If you notice the weight you are putting on your weighing system is not measuring consistently, the problem is likely either electrical or mechanical in nature and may require load cell testing. It is important to ensure that the load cell system is working properly. This determination typically requires a multi-meter and several diagnostic steps to complete.

METTLER TOLEDO load cells undergo a comprehensive test schedule during the Research and Development phase. In total 11 different areas are tested like metrology, environmental conditions, corrosion, shock/vibration and EMC behavior.
For serial load cells, each one is tested for temperature, linearity characteristics and sensitivity at the minimum. For higher accuracy classes, additional load celling testing is applied.  

All this assures the best quality and long reliable performance of METTLER TOLEDO load cells.

Load cell mounting is important for the final performance and should follow a specific load cell installation procedure. Beam load cells are bolted to a solid base with specific requirements for the surface quality. Column-type load cells typically require hardened load-receivers coping with the extreme stresses occurring.

For tank scale applications, you may need a jacking tool for the weigh module or load cell installation procedure. Watch our video on the Jacking Tool for MultiMount™ and PowerMount™ installation.

Each type of load cell requires a unique load cell mounting guide. There is not a one-size-fits-all METTLER TOLEDO load cell installation guide. As this is a quite complex topic, we recommend you consult your local METTLER TOLEDO representative for specific help with your application before installing load cells. They can provide load cell installation tips and best practices to ensure accuracy and offer a unique load cell installation guide for your application.

An alternative is to use weigh modules, which do provide a simple mounting interface at the highest accuracy. See our video How to Install Weigh Modules Quickly for more information.

Load cell testing with a multi-meter is possible, but also very limited. It is only possible to check resistance of excitation and signal lines. The correct values are provided in the specific product's datasheet. With a regular multi-meter it is not possible to check the performance or shift in sensitivity as the signals are typically too small for it. Also ingress failures cannot be detected with it.  For assistance with load cell troubleshooting, we recommend you reach out to your local METTLER TOLEDO representative.

A bad load cell can be investigated step-by-step with different methods of load cell testing. Often the scale signal is not stable anymore, which would be a first indication of a faulty load cell.  By loading each load cell in the scale consecutively, you can identify the one with the different behavior, which is likely the broken one. It might also help to knock cells slightly with a hammer. A constant signal shift is a strong indication of a defective cell.

For that first you need to install temporary support structures, which will carry the load of the scale instead of the load cell. Then disconnect the electrical wires, and remove the load cell. Insert the new load cell to the same place, and secure it mechanically. The next step is to connect the load cell electrically to the scale. Then you can remove the temporary support structures, and place the load again on the load cells. It is recommended to re-calibrate the scale once the load cell replacement is finished. Contact your local METTLER TOLEDO service team for assistance.