FSS-SMT Series Low Profile Force Sensor DESCRIPTION Honeywells FSS-SMT Series force sensors are designed to be Force sensors operate on the principle that the resistance of one of the most reliable force sensors available as illustrated silicon-implanted piezoresistors will change when the resistors by 20 million Mean Cycles to Failure (MCTF) at 25 C 77 F flex under applied force. The sensor concentrates force from rating. This low profile Surface Mount Technology (SMT) the applications, through the stainless steel ball, directly to the sensor allows for automated assembly on a printed circuit silicon-sensing element. The amount of resistance changes in board, often helping the customer to reduce assembly costs. proportion to the amount of force being applied. This change in circuit resistance results in a corresponding mV output level The FSS-SMT Series force sensor is designed to provide change. precise and reliable force sensing performance in a compact commercial-grade package. The sensor incorporates The sensor package design incorporates patented modular Honeywell sensing technology that uses a specialized construction. The use of innovative elastomeric technology and piezoresistive micromachined silicon sensing element. The low engineered molded plastics results in load excitation capacities power, unamplified, uncompensated Wheatstone bridge circuit up to 60 N (range dependent). The stainless steel ball provides design provides inherently stable mV output over the force excellent mechanical stability, and is suitable for a variety of range. potential medical and commercial applications. FEATURES AND BENEFITS POTENTIAL APPLICATIONS Surface Mount Technology allows for automated Medical assembly and may eliminate hand soldering Infusion pumps RoHS-compliant materials meet Directive 2002/95/EC Ambulatory non-invasive pumps Low deflection (approx. 30 m typical at full scale) helps Occlusion detection reduce measurement error Direct mechanical coupling of the actuation ball to the Kidney dialysis machines sense element reduces coupling errors and keeps Enteral pumps mechanical hysteresis to a minimum Product rating of 20 million MCTF at 25 C 77 F , subject Industrial to application variation, provides for consistent output over Load and compression sensing time and reduces repairs or replacements Small size minimizes space on the printed circuit board Variable tension control (PCB) Robotic end-effectors Provides enhanced sensitivity without compromising signal Wire bonding equipment integrity, resulting in low system noise and reducing 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-SMT Series 1 Table 1. Performance Characteristics (At 10 0.01 Vdc, 25 C 77 F .) FSS005WNGX FSS010WNGX FSS015WNGX FSS020WNGX 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 mV -30 0 +30 -30 0 +30 -30 0 +30 -30 0 +30 Null offset 4 Null shift mV 0.5 0.5 0.5 0.5 (25 to 0, 25 to 50 C) 5 mV 330 360 390 330 360 390 330 360 390 330 360 390 Span 6 % span 0.5 0.5 0.5 0.5 Linearity (BFSL) 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 % span 0.2 0.2 0.2 0.2 Repeatability Response time ms 0.1 0.5 0.1 0.5 0.1 0.5 0.1 0.5 (10 %FS to 90 %FS) 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 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 Plunger deflection m 26 28 33 30 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. Non-compensated EXCEEDING PRODUCT force sensors, excited by constant current (1.5 mA) instead of voltage, exhibit partial temperature compensation of OVERFORCE RATING span. 3. The output signal obtained when the zero force is applied to the sensor. Also known asnul orzer. Ensure the overforce 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 the voltage ratings given in Table axis. 1 are not exceeded 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. during any phase of 6. The maximum deviation of product output from a straight line fitted to output measured over the operating force sensor assembly to range. It is also 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. the board, as well as 7. The ratio of output signal change to the corresponding input force change. Sensitivity is determined by computing during the use of the the ratio of span to the specified operating force range multiplied by the supply voltage being used. 8. The maximum deviation in sensitivity due to changes in temperature over the operating temperature range, relative to sensor in the sensitivity measured at 25 C. application. 9. The maximum difference between output readings when the same force is applied consecutively, under the same Failure to comply with operating conditions, with force approaching from the same direction within the operating force range. 10. The maximum force which may safely be applied to the product for it to remain in specification once force is returned these instructions may to the operating force range. Exposure to higher forces may cause permanent damage to the product. Unless result in product 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