FSS Series Low Profile Force Sensor DESCRIPTION The FSS Series Force Sensor provides precise, reliable force The sensor package design incorporates patented modular sensing performance in a compact, commercial-grade package construction. The use of innovative elastomeric technology and at a cost effective price. The sensor features a proven sensing engineered molded plastics results in overforce capacities of technology that uses a specialized piezoresistive, up to three times the rated force. The stainless steel ball micromachined silicon sensing element. The low power, provides excellent mechanical stability and is adaptable to a unamplified, uncompensated Wheatstone bridge circuit design variety of applications. provides inherently stable mV outputs over the force range. The FSS Series Sensor delivered 20 million operations in Force sensors operate on the principle that the resistance of Mean Cycles to Failure (MCTF) reliability testing at 50C silicon-implanted piezoresistors will increase when the 122F . This test determines the number of possible sensor resistors flex under any applied force. The sensor concentrates operations at full scale until failure. force from the application, through the stainless steel ball, directly to the silicon-sensing element. The amount of resistance changes in proportion to the amount of force being applied. This change in circuit resistance results in a corresponding mV output level change. FEATURES AND BENEFITS POTENTIAL APPLICATIONS RoHS-compliant materials meet Directive 2002/95/EC Medical allows use in industries requiring regulation compliance Infusion pumps Low deflection (approx. 30 m typical at full scale) helps Ambulatory non-invasive pumps reduce measurement error Occlusion detection Direct mechanical coupling of the actuation ball to the sense element reduces coupling errors and keeps Kidney dialysis machines mechanical hysteresis to a minimum Enteral pumps Product rating of 20 million MCTF at 25 C 77 F , subject to application variation, provides for consistent output over Industrial time and reduces repairs or replacements Load and compression sensing Small size minimizes space on the printed circuit board (PCB) Variable tension control Provides enhanced sensitivity without compromising Robotic end-effectors signal integrity, resulting in low system noise and reducing Wire bonding equipment measurement errors Electrically ratiometric output accommodates supply voltage variations, leading to low ratiometricity error Low voltage supply allows for use in many battery powered applications High resistance to electrostatic discharge (ESD) meets ESD Sensitivity Classification Level 3B (8 KV), reducing special handling during assembly Sensor output has low sensitivity to many mounting stresses FSS Series 1 Table 1. Performance Characteristics (At 10 0.01 Vdc, 25 C 77 F .) FSS005WNSX FSS010WNSX FSS015WNSX FSS020WNSX Characteristic Unit Min. Typ. Max. Min. Typ. Max. Min. Typ. Max. Min. Typ. Max. Force sensing range N 0 to 5 0 to 10 0 to 15 0 to 20 2 Excitation Vdc 3.3 10 12.5 3.3 10 12.5 3.3 10 12.5 3.3 10 12.5 3 Null offset mV -30 0 +30 -30 0 +30 -30 0 +30 -30 0 +30 4 Null shift mV 0.5 0.5 0.5 0.5 (25 to 0, 25 to 50 C) 5 Span mV 330 360 390 330 360 390 330 360 390 330 360 390 6 Linearity (BFSL) % span 0.5 - - 0.5 - - 0.5 - - 0.5 - 7 Sensitivity mV/V/N 6.6 7.2 7.8 3.3 3.6 3.9 2.2 2.4 2.6 1.65 1.8 1.95 8 Sensitivity shift % span 5.0 5.0 5.0 5.0 (25 C to 0, 25 C to 50 C) 9 Repeatability % span 0.2 0.2 0.2 0.2 Response time ms 0.1 0.5 0.1 0.5 0.1 0.5 0.1 0.5 (10 %FS to 90 %FS) Input resistance k 4.0 5.0 6.0 4.0 5.0 6.0 4.0 5.0 6.0 4.0 5.0 6.0 Output resistance k 4.0 5.0 6.0 4.0 5.0 6.0 4.0 5.0 6.0 4.0 5.0 6.0 Plunger deflection m 26 28 33 39 10 Overforce N 15 30 45 60 Notes: 1. All force-related specifications are established using dead weight or compliant force. CAUTION 2. The range of voltage excitation which can be supplied to the product to produce an output which is proportional to force but due to ratiometricity errors may not remain within the specified performance limits. EXCEEDING Non-compensated force sensors, excited by constant current (1.5 mA) instead of voltage, exhibit partial PRODUCT temperature compensation of span. 3. The output signal obtained when the zero force is applied to the sensor. Also known asnul orzer. OVERFORCE RATING 4. The change in the null resulting from a change in temperature. It is not a predictable error as it can shift up and down from unit to unit. Change in temperature causes the entire output curve to shift up or down along Ensure the overforce the voltage axis. ratings given in Table 5. The algebraic difference between output signals measured at the upper and lower limits of the operating force range. Also known asfull scale outpu or simplyspa. 1 are not exceeded 6. The maximum deviation of product output from a straight line fitted to output measured over the operating during any phase of force range. The straight line through a set of points which minimizes the sum of the square of the deviations of each of the points from the straight line. sensor assembly to 7. The ratio of output signal change to the corresponding input force change. Sensitivity is determined by the board, as well as computing the ratio of span to the specified operating force range multiplied by the supply voltage being used. during the use of the 8. The maximum deviation in sensitivity due to changes in temperature over the operating temperature sensor in the range, relative to sensitivity measured at 25 C. 9. The maximum difference between output readings when the same force is applied consecutively, under application. the same operating conditions, with force approaching from the same direction within the operating Failure to comply with force range. these instructions may 10. The maximum force which may safely be applied to the product for it to remain in specification once force is returned to the operating force range. Exposure to higher forces may cause permanent damage to the result in product product. Unless otherwise specified, this applies to all temperatures within the operating temperature range. damage. Table 2. Environmental Specifications Characteristic Parameter 1 Operating temperature -40 C to 85 C -40 F to 185 F Shock qualification tested to 150 g Vibration qualification tested to 0 to 2 kHz, 20 g sine 2 MCTF (Mean Cycles To Failure) 20 million at 25 C 77 F Output ratiometric within supply range Notes: 1. The temperature range over which the product may safely be exposed without excitation or force applied. Under these conditions the product will remain in specification after excursion to any temperatures in this range. Exposure to temperatures beyond this range may cause permanent damage to the product. 2. MCTF is a basic measure of reliability for a non-repairable device. It is the mean number of cycles to maximum operating force over which a sensor can be expected to operate until failure. The mean value is determined statistically from a probability distribution for failures based upon test data. MCTF may vary depending on the specific application in which a sensor is utilized. 2 sensing.honeywell.com