FlexiForce® Sensors User Manual 02/24/06 I-Scan User Manual (Rev H) i
FlexiForce® Sensors User Manual Tekscan, Inc . 307 West First St reet , South Boston, MA 02127 Te l: 61 7 .46 4 .45 00 /8 00 .248 .366 9 fa x : 61 7 .4 64 .4 266 Email: m arket ing@t ekscan.com web: w ww.tekscan.
Table of Contents WELCOME ................................................................................................................................... 6 ISO .............................................................................................................................................. 6 INTRODUCTION ............................................................................................................................ 7 GETTING ASSISTANCE ............................................
WELCOME ISO Tekscan is registered to the following standard(s): • • 02/05/09 ISO 9001: 2000 ISO 13485: 2003 FlexiForce Sensor User Manual (Rev G) 6
INTRODUCTION This manual describes how to use Tekscan's FlexiForce Sensors. These sensors are ideal for designers, researchers, or anyone who needs to measure forces without disturbing the dynamics of their tests. The FlexiForce sensors can be used to measure both static and dynamic forces (up to 1000 lbf.), and are thin enough to enable non-intrusive measurement. The FlexiForce sensors use a resistive-based technology.
OVERVIEW This section outlines Sensor Construction and Application. FLEXIFORCE SENSORS The FlexiForce sensor is an ultra-thin and flexible printed circuit, which can be easily integrated into most applications. With its paper-thin construction, flexibility and force measurement ability, the FlexiForce force sensor can measure force between almost any two surfaces and is durable enough to stand up to most environments.
High-Temperature FlexiForce Sensors The High-Temperature HT201 sensor is available in the following force ranges* (as tested with the sample drive circuit). Sensor HT201-L Sensor HT201-H • • Low: 0-30lb (133N) force range High: 0-100lb (445N) force range * In order to measure forces outside specified ranges, use recommended circuit and adjust drive voltage and/or reference resistance APPLICATION There are many ways to integrate the FlexiForce sensor into an application.
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.
The saturation value is based on using the circuit and the values shown in the example circuit in the ‘Application’ section. In this example, the saturation force (maximum force) of each sensor is related to the RF (reference resistance), and can be altered by changing the sensitivity. The sensitivity of the sensor would be adjusted by changing the reference resistance (RF); a lower reference resistance will make the system less sensitive, and increase its active force range.
CALIBRATION Calibration is the method by which the sensor’s electrical output is related to an actual engineering unit, such as pounds or Newtons. To calibrate, apply a known force to the sensor, and equate the sensor resistance output to this force. Repeat this step with a number of known forces that approximate the load range to be used in testing. Plot Force versus Conductance (1/R).
SENSOR PERFORMANCE CHARACTERISTICS There are a number of characteristics of sensors, which can affect your results. This section contains a description of each of these conditions, and recommendations on how to lessen their effects. REPEATABILITY Repeatability is the ability of the sensor to respond in the same way to a repeatedly applied force. As with most measurement devices, it is customary to exercise, or "condition" a sensor before calibrating it or using it for measurement.
SENSOR LIFE / DURABILITY Sensor life depends on the application in which it is used. Sensors are reusable, unless used in applications in which they are subjected to severe conditions, such as against sharp edges, or shear forces. FlexiForce sensors have been successfully tested at over one million load cycles using a 50 lb. force. Rough handling of a sensor will also shorten its useful life.
SENSOR PROPERTIES STANDARD FLEXIFORCE SENSOR (MODEL A201) Sensor Properties Thickness Length Width Sensing Area Connector 0.008 (0.208 mm) 8” (203 mm) 6” (152 mm) 4” (102 mm) 2” (51 mm) 0.55” (14 mm) 0.375” (9.53 mm) diameter 3-pin male square pin (center pin is inactive) Typical Performance Force Ranges Operating Temperature Range Linearity (Error) Repeatability Hysteresis Drift Response Time Output Change/Degree F 0-1 lb (4.
