Beyond 1%: why load cell calibration is crucial

If you rely on accurate data from your load cells, you need to calibrate them on a regular basis.

Calibration compares the accuracy of your load cell against a recognised set of standards. Load cells generally have accuracies of between 0.03% to 1%. Beyond this 1% figure, data becomes too inaccurate for most industries and applications. In addition, your business might need to demonstrate accurate results for product liability and safety issues, and traceability to a National Standard. You might also need this traceability is you wish to work towards ISO9000. 

 

Why load cells need calibrating

When new load cells are delivered they are provided with a single point calibration, or a (usually optional) five point calibration figure. As you use your load cell, it is vulnerable to deterioration. The amount of deterioration varies according to the use, loads, situation and treatment of the load cells. Even in the cleanest of environments, for example, particles of dust can build up on a load cell and in time affect its accuracy.

Load cells can also become less accurate due to other faults such as electrical issues, mechanical forces, dirty environments, lack of maintenance or, faulty instrumentation such as readouts, or even just loose cabling.

All or just some of these environmental and usage conditions may cause your load cell to age and to ‘drift’ away from the levels of accuracy you’d expect or require. The problem is that you might simply not notice and continue to collect and act upon inaccurate data.

 

Load cell calibration for accurate data

Load cell calibration checks your load cell is working correctly. If so, happy days! If not, you may decide to ‘reset’ your load cell and check the calibration again at a set time period. Most standards, including ISO9000, set the maximum time between recalibration at two years. However, if the deterioration is greater than 1% from the last calibration date, you may consider a more frequent calibration schedule. It might also be quicker and more cost-effective to replace the load cells.

 

Load cell calibration at the Load Cell Shop

We offer a range of calibration services at The Load Cell Shop:

• Calibration of new load cells and instruments
• Re-calibration of your existing load cells
• Recalibration of your current load links
• Full calibration by UKAS accredited lab
• Proof testing
• Load cell output rationalisation

 

Calibration up to 10T Range (New Load Cells)

All our new load cells are supplied with single point calibration. If you wish to upgrade this to five point calibration, traceable to National Standards, this can be added to your new load cell at the time of purchase.

Five point calibration tests the repeatability and linearity of a load cell by testing it with incremental known loads, say 2T, 4T, 6T, 8T and 10T. The process is repeated, providing two set of results for each load. The difference between the two results is used to determine both its repeatability and its accuracy.

 

Calibration of load cells up to 10T, 30T and 100T Range

We offer recalibration of load cells in Compression or Tension. Our five point calibration is traceable to National standards, and we can do this in either a standard turnaround of 10 days, or an Express turnaround in just five days.

 

UKAS, ASTM E74 and ISO 376 Calibration

If you require a Certified Calibration Certificate, we can have your load cells or load cell and indicator calibrated by a UKAS accredited lab.

 

Calibration Load Links up to 30T Range

Recalibration of your load link in ranges up to 30 Tonne (tension only). You can also opt for additional Proof Testing to twice the S.W.L.

 

Rationalise Load Cell Output

When you buy a new load cell from us, we can rationalise the output to a specific value (0.0 to 2.200 mV/V) for a given unit of measure (e.g. 2.000mV/V at 1000kg). This is really useful if you don’t know how to recalibrate your electronics, and just want a matched replacement!

 

Need specific calibration services not listed here?

Contact us. We design, manufacture and distribute our own load cells, so we are true load cell experts. So, we can also provide full system calibration at our manufacturing base in Reading UK for most types of load cells with or without digital displays, load cell amplifiers, and load cell USB accessories.

Call with your calibration requirements – we’re happy to help.