Meaning of load cells or Force sensors:
Load cells or force sensors are devices that are designed to convert mechanical forces (like compressive and tensile forces) that act on them into electrical output signals. The output signal then can be measured so as to deduce the magnitude of the force that is being applied.
Force sensors are commonly called as Load Sensors or Load-cells. Load-cells are used to measure the force acting on an object. Both compressive and tensile forces, as well as elastic deformations can be measured.
Load cells, strain gauges, and force-sensitive resistors (FSR’s), are the three most common type of force-sensing technologies used to measure the impact of force on an object.
There are several routes by which force can be measured and determined utilizing force sensors.
The primary criteria that need to be taken into consideration to establish the type of force transducer that is best suited for a given purpose are: the expected measuring range, the required accuracy and the type of application.
There are different types of load-cell application depending on whether the force acting on an object is compressive, tensile or universal.
Precise force sensors are required wherever high accuracy is expected and the measuring range is small.
Various force sensors are needed in different industries depending on a plethora of decisive factors, therefore it is advisable to consult experts in this domain to ensure that the right type of load-cells and indicators are utilized for the relevant application.
Force sensors are available in varying characteristics such as sizes, shapes, capacity and performance. This makes it possible that it may be accommodated in machineries or testing equipment for diverse applications.
Major categories of Loadcells are listed below
- Compression only Sensors: Strain gauge based compressive force sensors refers to the devises which are used to measure push forces acting upon an object. This is an accepted method of quantifying the failure of materials, components, assemblies, and finished products.
- Tension only Sensors: Strain gauge based tensile force sensors refers to the devises which are used to measure the pull forces that act upon an object. These load cells that are designed particularly to measure tensile loads.
- Compression & Tension/Universal Sensors: Strain gauge based Universal type of tension and compression load cells can be used to measure both tensile and compressive loads that act upon an object.
- Multi-axis force sensor: Multi-axis force sensors are used to detect all kinds of forces that are applied via the 6 axes of a sensor. On the other hand, single-axis load cells are common in some fields such as physics and mechanical engineering. Single axis load cells utilize a single strain gauge to measure force in 1 axis.
How Does A Load cell Work:
Strain gauges are thin elastic materials that are glued inside load cells using specific adhesives. These strain gauges have a specific resistance that is directly proportional to its length and width.
The working principle of a load cell constitutes the use of several specific geotechnical instruments. And these will not work unless it’s connected to various sensors, one of which is a strain gauge.
When force is applied on a load cell, it either bends or stretches causing the strain gauge to move with it. And, when the length and cross-section of the strain gauge changes/alters due to these bending/stretching forces, the electrical resistivity also changes and the output voltage therefore varies accordingly.
A load cell works only when the strain gauge experiences some sort of a change in its resistance. The Wheatstone Bridge is commonly used to measure this change.
Load Cell Circuit:
Load cell circuit is also known as a Wheatstone Bridge Circuit.
If a load cell has four internal strain gauges, for example- A, B, C, and D as shown in the circuit above.
When the input voltage from a signal conditioner or digital display is connected to the bridge’s two opposite corners, namely C and D, then the output voltage is determined by connecting A and B resistors to the digital display’s signal side.
The circuit is said to be balanced when no load is applied to the load cell (that is when the Load=0). The strain gauge resistors will experience a change in resistance as soon as the load is applied, and this will change the voltage that flows through the circuit
As a result, the voltage between A and B will change, and this in turn will cause the weight on the digital display to change accordingly.
The analogue data from a Wheatstone bridge or a load cell is converted to readable units using an interpreter.
Difference between Load Cell and Strain Gauge:
Most people have this common query – what is the difference between a load cell and a strain gauge? People often find it difficult to distinguish between the two. One of the easiest methods that can be used to differentiate between the two would be: strain gauges have a single resistive element while a load cell has an arrangement of four strain gauges similar to a Wheatstone bridge arrangement as described earlier.
Various types of Load-cells:
- Button type
- Column type
- Single point
- Shear beam
- Bending beam load cells
- Dual shear beam
SushmaTM Force Sensors are highly accurate & compact in design and therefore are ideally suited for tensile, compressive or universal (both Compression & Tensile) force measurements.
They can also be used for a wide variety of static and dynamic measurement applications. Our product range of force sensors provide solutions that integrate effectively into a wide variety of industrial applications.
Each sensor that is manufactured is equipped with a calibration certificate. The devices are calibrated at Sushma Calibration & Test Labs Pvt. Ltd – which is a part of our group. The devices that are calibrated are accredited as per ISO 17025 (NABL Accredited Laboratory) traceable to National and International Standards ensuring highest levels of quality and precision.
Contact Us: Sushma is one of the reputed load cell manufacturers located in Bangalore. Contact us to know more about load cells uses, load cell price and load cell specification. Our experts will help you to either select a force sensor or to custom design it.