Load Cells and its types
The load cell is the part of any scale that measures the weight or force being applied. The cells convert the force of the load into an electrical signal, which is then read and displayed by a weight indicator. Load cells come in a range of different sizes, shapes, capacities and performance parameters.
Analogue load cells:
Analogue load cells are the most common solution. The output of the analogue load cell is a continuous millivolt (mV) signal proportional to the applied load. Further processing and Analogue-to-Digital (A-to-D) conversion are done in the indicator. Analogue load cells can easily be paired with a variety of digital indicators across multiple brands. The load cells are further differentiated by design e.g., Compression, Shear-beam type.
They are also known as canister type due to the shape of their housing; they are the most popular choice for weighbridges in India. Compression type load cells using self-aligning (rocker) mounting enable the structure to float freely on the load cells. Excellent sealing and environmental protection are feasible. It is recommended to go for IP68 (immersion) and IP69K (pressure cleaning) certified products and with stainless steel construction for longer useful life.
Available as a single or double ended shear beam this type of load cell can offer a slightly lower profile and less sensitivity to side-loads, but often with poorer sealing and corrosion resistance. These load cells are more advantageous in silo/ vessel weighing where rigid connections and head-room constraints are an issue as compared to a vehicle weighbridge where sealing and protection are very important.
Digital load cells:
Digital canister load cells are a popular choice in weighbridges. Unlike conventional analogue load cells, which rely on external wiring, junction boxes and A to D circuitry, digital cells offer additional protection from the unwanted electrical interference that can affect analogue load cells. Digital load cells can be pre-linearized, which allows faster installation and calibration, as well as featuring built-in diagnostic tools.
Load cell accuracy:
Keep in mind that the accuracy of a load cell has no relation to it being analogue or digital, compression or shear-beam type. All of these can offer an accurate and dependable solution, provided the load cell fulfils the accuracy criteria as set by the relevant certifying bodies.