Cooper Instruments & Systems ELF 4200 Flexiforce Paper Thin Sensor - Manual (Page 55)

CF10 52 6/24/08 Rev. H
over a prolonged period. After each installation, visually inspect your sensors for physical damage. It is also
important to keep the sensing area of the sensor clean. Any deposits on this area will create uneven loading,
and will cause saturation to occur at lower applied forces.
Sensor Temperature Sensitivity: The operating range for FlexiForce sensors is from 15°F (-9°C) to 140°F (60°C).
FlexiForce sensor output may vary up to 0.2% per degree F (approx. 0.36% per degree C). In general, your
results will vary if you combine high loads on the sensor with high temperatures. For loads of less than 10 lbs.,
the operating temperature can be increased to 165 °F (74 °C). To ensure accuracy, calibrate the sensor at the
temperature at which it will be used in the application. If the sensor is being used at different temperatures,
perform a calibration at each of these temperatures, save the calibration files, then load the appropriate
calibration file when using the sensor at that temperature. FlexiForce sensors should be stored at temperatures
in the range of 15°F (-9°C) to 165°F (74°C).
Sensors: The FlexiForce sensor is an ultra-thin (0.005.), flexible printed circuit. It is 0.55. (14 mm.) wide and 9.0.
(229 mm.) in length. Sensors are available in three full-scale force ranges: Low (25 lbf ), Medium (150 lbf ), and
High (1000 lbf ). The active sensing area is a 0.375. diameter circle at the end of the sensor. The sensors are
constructed of two layers of substrate, such as a polyester film. On each layer, a conductive material (silver) is
applied, followed by a layer of pressure-sensitive ink. Adhesive is then used to laminate the two layers of
substrate together to form the sensor. The ‘active sensing area’ is defined by the silver circle on top of the
pressure sensitive ink. Silver extends from the sensing area to the connectors at the other end of the sensor,
forming the conductive leads. The sensor acts as a variable resistor in an electrical circuit. When the sensor is
unloaded, its resistance is very high (greater than 5 Meg-ohm); when a force is applied to the sensor, the
resistance decreases. FlexiForce sensors have been successfully tested at over one million load cycles using a
50 lb. force. See also "Sensor Life / Durability".
Settings (Record Menu): Settings: brings up the Recording Parameters dialog box, which allows you to change
the current recording parameters. Under ‘Recording Type’, there are three possibilities that may be selected.
See "Recording Parameters".
Start (Record Menu): The "Start" command is used to make a recording (movie). When Start is selected, the
software begins recording a movie of the current Real-time window data using the settings that have been
selected (see Settings menu item). When data is being recorded, the Recording In Progress message will
appear (shown below), and the Recording On icon (on the Main Tool Bar) will become active (the red circle will
become grayed out, and the square "Stop" button -- black color -- will become visible). If .Triggering. is in effect,
and Record is selected, the Waiting for Trigger message will be displayed until the trigger force is reached.
Movies created by the ELF system are stored as *.flf files.
Status Bar (Main): The Main Status Bar provides the user with feedback about what is happening inside the ELF
software. It will either say .For Help, Press F1., or will give a description of whichever Toolbar icon is under the
cursor. The Main Status Bar is located at the bottom of the Main Window.
Status Bar (Movie Window): The Movie Window Status Bar is located at the bottom of the Movie Window, and
displays the Frame count (the current frame number vs. the total number in the movie).
Status Bar (View Menu): The "Status Bar" option is used to display or hide the Movie and Main Status Bars.
These status bars can be toggled by clicking this menu item on and off. If a Real-time window is active, this
menu item affects the Main Status Bar. If a Movie window is active, this menu item affects the Movie Status
Bar.
Stop (Movie Toolbar Playback Controls): Stops playback.
Stop (Record Menu): The "Stop" command will cause the software to stop recording the active Real-time window,
even if the correct number of movie frames (as selected in Settings) have not yet been recorded.
Strip Chart (View Menu): The "Strip Chart" option is the default display mode, where force value is displayed on
the Y-Axis and elapsed time is displayed on the X-Axis.
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Temperature Sensitivity: See "Sensor Temperature Sensitivity".
Threshold: Refers to a value within the Recording Parameters that is set by the user. The Threshold may be set
for each individual COM port, so that each sensor has a different Threshold. This may be used in combination
with the Trigger Force value to begin recording when force is exerted on a specific sensor. See "Recording
Parameters".
Tile (Window Menu): The "Tile" command arranges multiple windows in an overlapped fashion, either vertically or
horizontally.
Toolbar: The Toolbar provides some of the same options as the Menu Bar, but with icons replacing drop-down
menus. It is located directly below the Menu Bar, at the top of the Main Window. Note that not all items in the
Menu Bar have a corresponding icon on the Tool Bar.