Tags – What Affects Accuracy of Weigh Scales

If your business depends on vehicles being weight compliant, then having vehicle weighing systems that provide accurate readings is critical.

Be it a modular weighbridge or a portable axle pads, these scales need to work accurately to avoid potential fines or in extreme cases, fatal accidents.

Unfortunately, even scales that are of the highest quality can be affected by a number of different factors which can affect accuracy.

So, being aware of these can help you spot any external factors that may be playing a part, as it could indicate whether or not you need a new weighing system.

Here are 3 factors that could be affecting the accuracy of your weighing scales.


1. Load Cell Accuracy 

A load cell is one of the most important components in any digital weighing scale: scales cannot function without it.

Essentially, when an item (in this case a vehicle) is placed on a scale, the load cell bends and it’s this movement which measures the weight. Therefore, if the load cell is not working properly, this is going to cause inaccurate readings.

There are a few things that can affect the load cell, these are 3 of the most common:

  • Response Time: this is how long it takes the load cell to stabilise and give a reading. Whilst it doesn’t sound like an issue, those businesses that are fast-paced and need to quickly get vehicles on the road, their readings may not be as reliable as they’ve not waited long enough for the accurate weight.
  • Creep: if the vehicle is left on the scales for too long, creep can start to take effect. This is the change in the measured weight if the load cell stays under pressure for too long.
  • Temperature Changes: if the temperature where the scales are placed is constantly changing, this can cause errors in measures. For example, increase in temperature can cause load cells to expand, thus providing inaccurate readings. 


2. Environmental Factors 

Anything that surrounds the scale that can cause a negative effect on its weighing ability is an environmental factor.

Here are a few environmental factors that can affect weight scale’s accuracy:

  • Vibration: if there is any other equipment near the scales that vibrate, ventilation systems for example, this can lead to inaccurate readings as the load cell cannot measure the weight properly.
  • Dirt: if scales are not regularly cleaned, a buildup of dirt can actually increase the weight when objects are placed on the scale: only the load cell should carry the weight but if there’s a significant amount of debris, this makes it impossible to weigh the object alone.
  • Wind: airflow will affect the weighing scales: the more airflow, the pressure that is put on your scale which affects how the weight is measured. 
  • Shock Loading: suddenly adding heavy materials onto the scales will increase the force placed upon it. And if this exceeds the weight limit, it can cause damage to the load cells which will therefore give inaccurate readings.


3. Interference 

As load cells send an electrical signal to the scale’s digital indicator, any kind of interference during the process will result in inaccurate readings.

The common types of interference include:

  • Moisture: it’s normal for condensation or moisture to build up, however it can affect the load sensor or cables: if these get too wet then the electrical inputs and outputs will not be able to send accurate signals.
  • Temperature: a rise in temperature will cause the voltage in wires to drop, which can mean the controller displays results that are actually different to the load cell’s output.
  • Radio Frequency Interference: (RFI), is an electrical noise source that can affect weighing accuracy, i.e. lightning or two way radios will affect the electric signals transmitted from the scale and show incorrect readings.


The Bottom Line

No matter what type of weighing system you have, it’s important to carry out routine checks to ensure there are no external factors that are causing your scale to give inaccurate readings.

Otherwise you open yourself to potentially fatal risks.


If you’d like to know, please get in touch today.

In the meantime, check our Vehicle Weight Checker solutions.

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