FAQ`s

What are the different units of force and what do they mean?
In the US, the most widely used unit for force is the pound. It was historically defined in relation to avoirdupois units, but currently this definition has been replaced by one which is expressed in metric units. The SI unit for force is the Newton (N), which is defined as the force required to accelerate one kilogram of mass at a rate of one meter per second squared. Other units of force include the dyne, the kilopond, the poundal, and the grain, but these are not nearly as common and utilized mostly in specialized cases.

Please visit the conversion table > to compare different units of mass and force.

Why are there so many different types of load cells?
The abundance of load cell designs stems from the even greater variety of load cell applications. For instance, donut load cells are commonly used to monitor bolt tightening, which requires that they have an unthreaded through-hole and a low profile. Another example is the cantilever beam, typically employed in weighing applications which require it to be anchored at one end and hold weight at the other, hence the elongated body. In truth, the many different types of strain gauge load cells all operate on the same basic principles—the piezoresistive effect and the Wheatstone bridge configuration—so in this sense, they are really not very different at all.

What can affect a load cell’s measurements?
Many variables can influence a load cell’s performance characteristics. Testing errors can arise from improper loading conditions like off-center loading, side loading, and torque loading. Set-up conditions related to the cleanliness, hardness, and flatness of the upper and lower loading surfaces may also introduce inaccuracies. Additionally, environmental conditions such as temperature, humidity, and electrical noise, as well as high vibrations, extended cycling, and others are able to impact the output signal. For these reasons, it is important to consider all such factors before choosing a load cell, and to contact the manufacturer to ensure that the load cell matches the application.

What are the different performance specifications and what do they mean?
Each specification gives the maximum error range for a given load cell’s output (usually as a percentage of full scale output) in regard to a specific characteristic. There are four main specifications which are critical to understanding load cell performance. First, non-linearity determines how much the output deviates from a perfectly straight line. Second, hysteresis gives the difference between the descending and ascending outputs. Third, repeatability is the measure of how consistently the output repeats from run to run. And fourth, thermal effects show the error in output that occurs as the result of a temperature change. The combined error of all these specifications does not exceed one percent for almost all load cells, and it may be as low as a few hundredths of a percent for the most precise.