
Sensing technology and system configuration
Hall Effect
Hall Effect force plates and force sensors are economical, lightweight, portable instruments that function as standalone systems for specific applications. Their patented design uses Hall Effect sensors to measure all six force components and allows for high overload protection on all axes.Multiple Hall Effect sensors and magnets are arranged inside the force transducer. The sensors measure magnetic field changes that occur when integrated spring elements deflect due to the forces and moments acting upon the top surface.
Signal amplification occurs inside AMTI’s Hall Effect-based products, eliminating the need for an external amplifier and limiting the necessary system components to an analog or digital data cable. If the digital output is used, an interconnection box may be used to connect two force plates or force sensors to a computer.
Mounting is possible with Hall Effect force plates, but is typically unnecessary for the recommended applications.
The trade-off for this simple design is lower sampling rates and less stiffness, which results in lower natural frequency of the platform top.
Strain gage
Most of AMTI's products use strain gage technology, which provides the most accurate and flexible force measurement solution. (Hall Effect platforms offer comparable measurement performance when employed for their intended use.)The working surface of an AMTI strain gage-based product is supported by thin-walled cylindrical sensing elements. Each element is instrumented with strain gages, which are excited by a constant voltage supplied by the connected signal conditioner.
When a load is applied to the working surface of the transducer, strains occur in the walls of the supporting cylinders. This changes the electrical resistance of the strain gages and produces a change in the output voltage that is proportional to the forces being applied. AMTI's patented arrangement of strain gages isolates the signals caused by individual forces and moments, allowing them to be accurately and separately quantified.