FlexiForce user manual

02/05/09 FlexiForce Sensor User Manual (Rev G)
10
SENSOR LOADING CONSIDERATIONS
The following general sensor loading guidelines can be applied to most applications, and will
help you achieve the most accurate results from your tests. It is important that you read the
Sensor Performance Characteristics section for further information on how to get the most
accurate results from your sensor readings.
SENSOR LOADING
The entire sensing area of the FlexiForce sensor is treated as a single contact point. For this
reason, the applied load should be distributed evenly across the sensing area to ensure accurate
and repeatable force readings. Readings may vary slightly if the load distribution changes over
the sensing area.
Note that the sensing area is the silver circle on the top of the sensor only.
It is also important that the sensor be loaded consistently, or in the same way each time.
If the footprint of the applied load is smaller than the sensing area, the load should not be placed
near the edges of the sensing area, to ensure an even load distribution.
It is also important to ensure that the sensing area is the entire load path, and that the load is not
supported by the area outside of the sensing area.
If the footprint of the applied load is larger than the sensing area, it may be necessary to use a
"puck." A puck is a piece of rigid material (smaller than the sensing area) that is placed on the
sensing area to ensure that the entire load path goes through this area. The puck must not touch
any of the edges of the sensing area, or these edges may support some of the load and give an
erroneous reading.
The FlexiForce sensor reads forces that are perpendicular to the sensor plane. Applications that
impart "shear" forces could reduce the life of the sensor. If the application will place a "shear"
force on the sensor, it should be protected by covering it with a more resilient material.
If it is necessary to mount the sensor to a surface, it is recommended that you use tape, when
possible. Adhesives may also be used, but make sure that the adhesive will not degrade the
substrate (polyester) material of the sensor before using it in an application. Adhesives should
not be applied to the sensing area; however, if it is necessary, ensure that the adhesive is spread
evenly. Otherwise, any high spots may appear as load on the sensor.
SATURATION
The Saturation force is the point at which the device output no longer varies with applied force.
The saturation force of each sensor is based on the maximum recommended force specified by
Tekscan, which is printed on the system packaging or the actual sensor, along with the
"Sensitivity."