In business for more than 30 years, the scale experts at Arlyn Scales have worked very hard to ensure the scales that we produce are rugged, accurate, and affordable. Headquartered right here in the U.S., Arlyn Scales can listen to our customers and make quick adjustments to ensure our products are always on the cutting edge when it comes to weighing technologies.
At Arlyn Scales, we do all we can to ensure our scales are accurate in a variety of industrial environments. But even the most modern digital scales can give inaccurate readings in certain conditions.
Because we’re often asked about the factors that affect a scale’s accuracy, we thought it would be a good idea to expand upon some of the top factors that can greatly affect the accuracy of any scale.
Factors That Affect the Accuracy of an Industrial Digital Scale
Environmental Factors
There are many environmental factors that can affect the accuracy of your digital scale, including:
- Shock loading – Suddenly dropping heavy materials onto a scale that exceeds the maximum weight capacity can damage the load cell and other components.
- Wind loading – Scales of all kinds can be affected by air movement. The most sensitive of indoor scales can even be affected by small amounts of air movement generated from air ducts, or air conditioning units.
- Vibration – Sensitive load cells can misinterpret vibrations from equipment that is close by and in turn provide incorrect weight readings.
- Unclean scales – Scales that are not regularly cleaned can build up weight due to dirt and other objects on the scale platform, and scale components. Also, the weight on the scale must be completely supported by the load cell(s), which is impossible if there is significant debris build-up underneath the scale itself.
- Differences in air pressure – Digital scales can provide inaccurate measurements if the air pressure from the calibration environment is different than the operating environment.
Accuracy of the Load Cell
The load cell is the most important component of any digital weighing system, and a malfunctioning load cell can result in severely inaccurate weight readings.
There are several parameters that you should be familiar with when looking to understand how load cells function.
- Temperature – Sometimes a scale’s load cell will be exposed to large temperature variations, which can lead to inaccurate readings.
- Nonlinearity – The max deviation of a load cell’s calibration curve as it relates to a straight line.
- Non-repeatability – Variations made when the same object is measured in the same manner over and over again.
- Hysteresis – The difference in scale output when the same load is measured twice, once increasing from a zero-weight, and a second measurement that is decreasing from the load cell’s max weight rating.
- Creep – The change in the measured weight when an object is left stationary for a long period of time.
- Response time – The time that it takes for a load cell to settle and provide an accurate reading. Response time can be a major issue in instances where there is little time available between weights.
Interference
Load cells typically work by sending an electrical signal, which is processed by some type of weight controller that then outputs the weight onto the scale’s digital indicator. Interference during any part of this process can lead to inconsistent readings.
Below are just a few of the more common types of interference that we see when working with our customers:
- Temperature – As temperatures increase wire resistance increases as well, causing voltage to drop, which can lead to the scale controller displaying results that are actually different from the load cell’s output.
- Moisture – From time to time, condensation or moisture can build up on the load sensor, which can affect electrical outputs and cause interference in the signals being sent from the load cell to the display indicator.
- RFI and EMI – These can create additional input signals, or noise that can also cause the scale controller to display an incorrect weight.
Factors in Loading
Not only can inaccuracies in weighing result from the scales and their internal components, but also from the loads themselves, and how they’re loaded or unloaded.
A few things to watch out for when it comes to properly loading or unloading an industrial scale include:
- Ensure that the mounting structure located on the floor underneath the scale can fully support the weight of not just the scale, but its components and its load without flexing. A solid flat surface is essential when weighing objects on your digital scale.
- Loads that are not properly aligned can cause load cells to interpret the force as weight and generate an inaccurate reading.
- It’s very important to ensure the mounting hardware is functioning properly as this is where the weight of the load placed on the load cell is channeled.
- Add cross braces on scales that have less than ideal support legs to help reduce instances where support legs will spread under strain and lead to an inaccurate weight reading.
Arlyn Scales – Your Source for Highly Accurate Industrial Scales
At Arlyn Scales, we’ve been providing our customers with highly accurate industrial scales that stand the test of time for more than 3 decades. If you’re purchasing a strain gauge scale from Arlyn, you’ll be buying a scale that features stainless steel load cells that are machined and output-matched in our Long Island factory to ensure they’re both accurate and rugged.
If you’re looking for an even more rugged and accurate weighing solution, Arlyn Scales has also developed their own patented Surface Acoustic (SAW) line of scales, which are 10-20 times more accurate than strain gage scales, and offer accuracy that rivals magnetic force restoration scales, but at about 1/3 the cost. Whatever type of scale you choose to purchase from Arlyn Scales, we’re committed to providing the highest level of support both during and after the sale. We’ll work with you to determine what factors may cause issues with scale accuracy, and find a solution that meets your needs. For more information on any of our scales, don’t hesitate to reach out to our team today by phone at 800-645-4301, or through our online contact form.
