Weighing Technology (Loadcell Types)
A problem that often occurs when someone purchases a scale is in regards to the underlying loadcell type contained within the scale itself. Think of this as the engine and if your application requires a particular type, buying the wrong one is going to have undesirable consequences. The quality of the results will depend on the type of technology being used. There is a reason why one item may cost a couple hundred dollars while an item that appears to have similar specs costs a couple of thousand.
Electromagnetic Force Compensation
Laboratory environments usually prefer a force restoration balance which is an advanced type of eletromechanical balance that utilizes an electrodynamic converter with a permanent magnet working together to convert the force applied to the platform into a proportional electric current and then return the position to equilibrium as the force is removed. This is the most expensive type of technology but it is needed by laboratories because of the benefits of the repeatability and stability.
The number one reason to purchase a force restoration balance is its ability to successfully measure the weight being filled on the platform. Speed is a major factor in keeping up with the flow at an acceptable level so the end-user can stop filling at the appropriate measurement. This is the weakness of a low cost scale that makes them unacceptable in the laboratory.
Electromechanical Compensation
This is the most common type of loadcell on the market. More commonly called strain gauge, it will take the load on the platform and convert the force to a digital signal that can interpret the weight electronically. This kind of technology suffers several drawbacks that make them unsuitable for the laboratory market. Brand name is less of a factor since it is the technology itself that suffers the limitation rather than the quality of the technology.
It is perfectly fine to use an electromechanical loadcell in a balance that you put a sample on the scale and record it. It may continue to creep up or down especially if the scale has not been warmed up for 30 minutes. Light samples won't register because the zero tracking will automatically reset the weight to zero since it is interpretting the small amount of force applied as sensitivity drift.
Rice Lake balances feature a unique tuning fork sensor that sets them a tier above the strain gauge loadcell type while maintaining economical pricing. Its strength is in its simplicity. Quality results are achieved with better accuracy and stability while warming up in practically no time at all. This is because it does not need to convert an analog to digital signal like the other types of balances. They are faster and more reliable than strain gauge but there are a limited number of divisions available in the product line and they don't have some of the other nice features found in magnetic force restoration balances.