As the winter weather finally arrives in the UK, load cells used outside may require additional protection to ensure their accuracy in a variety of conditions. So button up your coat and pop on a hat, as we explore four factors that can affect even the most robust of load cells.
1. Large temperature changes
As a country with a temperate climate, as a rule, Britain experiences less extremes of temperature than other countries. However, consider last week’s temperatures, running at around 16 degrees, in contrast with temperatures this week where some locations experienced temperatures down to minus 6 degrees. Whilst these might not affect the performance of the more robust types of load cells, it might affect the item/s they are attached to. Contraction and expansion might love the item being weighed or monitored in its mountings, causing erratic readings.
Some people know when the atmospheric pressure has changed, but most of us are blissfully unaware. The same does not apply to load cells. If the item you are weighing or monitoring items sit within a pressurised environment, the load cells must be calibrated in those conditions too. Avoid location where pressures might fluctuate too wildly.
3. Wind loading
Wind is a variable that can quickly turn reliable load cells weight readings into nonsense. If you’re trying to weigh something in a 30mph cross wind, for example, it can create different readings on the side facing the wind (lighter weight) and the side sheltered (heavier). If your site is prone to wind, you should install a higher capacity load cell system to avoid overloading the cells on the sheltered (leeward) side.
Inside, the air currents from an air conditioning system, blow heaters or ceiling fans can equally affect measurements using a low capacity platform scale or similar. If turning off these units is not an option, then consider covering the scale with a clear cover to deflect and divert the air stream.
4. Changes to cabling
Load cells can be bought that are sealed against water and moisture, but the readings they give will only be as accurate as the cable those signals travel along. So, it’s vital that your cabling system and junction box are watertight and protected from moisture wicking up external cables. The same applies to extremes of temperature that affect your cables. Temperature fluctuations can create resistance changes in the cable, which cause excitation changes, which affect the load cell signal. To solve the issue, use use six-wire load cell cable or buy wireless load cells instead!
Load cells play an important role in monitoring the effects of weather, including various aspects of snow. Check out our previous article on how load cells are crucial to the in-depth study and analysis of snowfalls, snow melt and snow compaction, plus the analysis of snow crystals, and the design of snow shoes.
And if we do get any significant snowfall, you might want to build your own snow scale in the back garden: here’s how. No need to upset your other half by taking apart their favourite kitchen scales just as they’’re about to cook the Christmas cake – order your load cells from us instead, and use a Raspberry Pi or similar for the data processing and display!
Keep it clean
Weighbridges for vehicles and weighing platforms for livestock are particularly prone to contamination by the by-products of wet weather or snow: mud! A surface layer of mud and debris can affect the accuracy, whilst caked mud can affect the physical performance too.
Whilst you could clean it yourself with a pressure washer, weighing specialists Avery suggest that.
“The water jet force required to remove dirt and debris from around a weighbridge’s critical weighing points can, if not performed correctly, damage load cells and cabling.”
So, always clean with caution, (here’s Avery’s helpful guide ), or call in the professionals.
Load cells available whatever the weather
If you need replacement load cells, call us. We can supply load cells for a wide range of applications and operating conditions, and we can calibrate them too. Just call or email with your requirements, or check out the extensive stock at our online load cell shop.