Using Load Cells to Weigh Things
Load Cells are an important part of our everyday lives but like transistors or capacitors most of us do not even realise they exist or take any notice. If we think about the number of things that are weighed we would usually only think of our Salter scales in the bathroom or the digital BMI measurement devices found in most swimming pool leisure centres, not
load cells. Taking a measurement of weight or mass is however a fundamental part of our lives and found in every aspect from creating that delicious meal, posting a parcel, filling up your petrol tank to how much our grocery costs.
In business load cells become even more important for all sorts of different reasons, the primary perhaps being to accurately measure how much of an item is being sold or included in the manufacturing process. Scales are found under conveyor belts, on loading bays, silos and large tanks and even in trucks. The generic and standard method a load cell operates is typically called a strain gauge. Here the weight of the item being measured is physically loaded onto the cell, this forces the material to “strain” and this change can then be translated into a measurement of mass or weight.
There are a number of difficulties which this method of measurement, which in essence all stem from the same problem, the
load cell is “strained” and as with any material which is regularly put under pressure and has physical changes in attributes this shortens the life cycle of the device. Another inherent problem with this kind of strain is that it is subject to damage from sudden or unexpected forces, for example a load not intended for the device is applied or a sudden shock or vibration would affect the cell and its measurement.
Fortunately there is an alternative to such a device call the Capacitive
Load Cell. This is uniquely different in that the cell itself does not strain, instead the capacitance is measured and in a non-contact manner. As well as being able to handle sudden shocks and vibrations, this device is also able to take over-loading without being damaged. Another benefit of this kind of measurement is that it is already electrical and does not need to be “read” which allows for simpler integration into electronic systems with the readout device capable of being much further away from the load than traditionally expected.
