A force transducer measures the applied force from the proportional deformation of a spring element and converts it into transmitted output signals sent to indicators, controllers, data acquisition systems, and computer systems. As a general force measurement rule, the greater the amount of force, the more the spring is deformed.
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How Force Transducers in Balancing Scales Work
A transducer or load cell is the main component of a mechanical weighing scale. In terms of technical accuracy, these devices convert one form of energy (gravitational force, which is the weight of an object) into another form of energy (electronic signal). The devices provide a sensor display that measures accurate weight.
According to the laws of physics, when you apply pressure or force on a piece of metal, it changes shape (however, that change may not be physically visible to you). A force transducer measures this change and displays it in the form of gravitational force or energy. This gravitational force is called the physical mass of an object. A micrometer is used in the transducer, which interprets that micro change. This is the simple principle on which force transducers or load cells work in a weighing sensor or balancing scale. One measured input is translated into some accurately-measured output by the transducer.
In general, a force transducer can be viewed as an electrical, electronic, digital, and mechanical device. It is also an electromechanical device that combines the principles of modern physics.
- Input and Output
- The weight or force placed on a machine is called input, and the data we receive on the LED or digital indicator is output. Input in technical terms is the parameter that will be measured by the load cell. The cell's job is to make sure that an accurate output is received easily.
- Elastic Load-Bearing Element
- Many blueprints of force transducers contain elastic load-bearing elements. The main job of these elements is to deflect after a load has been placed and help the built-in sensor to measure the amount of deflection. The sensor, in many designs, is a secondary transducer, which facilitates more accurate data. The secondary transducer converts the quantity of deflection into electronic signals that you see on the screen.
- In general terms, force transducers are also known as elastic devices consisting of different elements such as beams, rings, circles, and cylinders.
Applications of Force Transducers
A system of parts rather than a single piece of machinery, force transducers are common in many industries for many applications. The manufacturing, automotive, medical, defense and assembly line industries use force transducers in applications like quality assurance in manufacturing and assembly, press monitoring, biomechanics, product testing, materials testing, dynamic weighing of moving vehicles, and wheel force measurement. They are also used as kitchen scales and small, portable tire pressure gauges in the home. These force measurement systems produce data by analog or digital electronic, pneumatic or hydraulic outputs. They are inexpensive to produce and long lasting. They also vary in size and weight, depending on their intended use. A force transducer can be as large as hundreds of tons when it is meant for industrial buildings or as small as a gram for minuscule medical measurements. Environmental hazards, placement, and size are all things that require consideration to make sure that those in the environment with a force transducer, particularly the larger ones, are safe.
Types of Force Transducers
The object or material being measured by a force transducer must exhibit some elasticity in order to work correctly. Their components include a scale platform, an electronic system for the output, voltage, and a strain gauge sensor or load cell. There are four main types of force transducers, all ranging in methods of measuring and construction. Force transducers are used in a variety of measuring devices that are used across industries.
- Strain Gauge Load Cells
- The most popular type of force transducers. This category includes many other sub-types such as elastic elements, electrical resistance strain gauges, foil strain gauges, semiconductor strain gauges, thin-film strain gauges, and wire strain gauges (all having dissimilar working principles). Strain gauge load cells are the most common type and have multiple elastic elements that measure the force in certain spots.
- Piezoelectric Crystal Load Cells
- Help you gauge the quantity and intensity of electric charges formed on a crystalline material. Such devices have a charge amplifier to measure the change. In addition, these devices have piezoelectric crystal sensors that work together to help the user fetch the measurement. Piezoelectric crystal force transducers use quartz under pressure, producing an electrical charge proportional to the mechanical load applied. Both are translating a deformation of their measurement structures, a coil for the strain gauge and a crystal for the piezoelectric, into a readable signal.
- Pressure Load Cells
- Available in two types: hydraulic and pneumatic load cells. The hydraulic type includes liquid oil that is set with a preload pressure. While the pneumatic type is quite similar to the hydraulic type, the counteracting pressure is relational to the force in these machines and can be seen on the pressure dial. Hydraulic load cells use pressurized liquid to measure force, while pneumatic systems use force and pneumatic pressure. The counteracting pressure is measured and displayed. Like load cells, force transducer models must be chosen with care by consumers since many factors are involved.