Originally Published MPMN January/February 2009

SPOTLIGHT

Sensors and Transducers

Liquid-level sensor

A noninvasive, self-adhering liquid-level sensor has a miniature design and integral circuitry, enabling the unit to monitor liquid level by being placed on the outside of a fluid reservoir. The performance of the Sonic Eye–series sensors is not affected by the optical or dielectric properties of the fluid or container. In addition, the sensors do not pose material compatibility or contamination issues. Designed to be used in fluid-monitoring applications involving hazardous chemicals or biomedical fluids, the sensors operate with 5–24-V dc input and a choice of output options, including transistor-transistor logic, sourcing, and sinking.
Cosense Inc., Hauppauge, NY
www.cosense.com

Fiber-optic pressure sensor

Based on miniature optomechanical systems (MOMS) technology, a fiber-optic pressure sensor exhibits better thermal performance and stability than previous-generation models, according to its manufacturer. Demonstrating better thermal performance and greater stability than previous sensor generations, the FOP-M260 uses white-light Fabry-Perot interferometry technology, ensuring accurate and reliable measurements under all field conditions. With a diameter of 260 µm, the sensor is smaller than a 1 French catheter and half the size of the company’s FOP-MIV pressure sensor.
FISO Technologies Inc., Quebec City, QC, Canada
www.fiso.com

Tension and compression load cell

A structurally improved tension and compression load cell increases output symmetry and accuracy. Available with metric threads, the LCF400 is offered in 500- to 5000-lb versions. In addition, it comes with 3-mV/V, ±5-V dc, ±10-V dc, and 4–20-mA outputs, features one-piece construction, and uses heat-treated Type 17-4 stainless steel. The modified unit also offers zero-joint failure, resists high extraneous loads, and can handle off-center loading. Featuring a compact height and metal-foil strain-gauge technology, the load cell has nonlinearity of ±0.10%, bridge resistance of 700 Ω, and deflection of 0.002 to 0.005 in. nominal. The standard LCF400 load cell can be modified or customized to meet specific requirements.
Futek Advanced Sensor Technology Inc., Irvine, CA
www.futek.com

Air-pressure sensors

High-accuracy pressure sensors are suitable for air-pressure measurements in oxygen concentrators, respirators, and ventilators. With a maximum weight of 1.3 g and dimensions of 21.29 × 16.71 mm, P6060 sensors contain a piezoresistive sense element in a surface-mount package. Using a 5-V input, the sensors provide a 0.5- to 4.5-V dc linear analog amplified output proportional to pressure. Users can specify digital outputs that conform to their SPI protocols. Internal temperature compensation achieved using an application-specific integrated circuit ensures an accurate ±1% of span total error band over a temperature range of 0° to 60°C. Available pressure ranges include 13 in.H2O and 0–1 through 0–75 psia, psig, and psid. The electromagnetic interference/radio-frequency interference– and electrostatic discharge–protected sensors do not experience mounting position effects and provide a fast response. They can be configured to accommodate custom pressure ranges and are available with various port connections for specific application requirements.
Kavlico Corp., Moorpark, CA
www.kavlico.com

Teflon-coated temperature sensors

Two Teflon-coated sensors are suitable for use in environments in which resistance to chemicals and humidity is required. The RBS-8097 RTD and the JBS-8078 thermocouple are coated with Teflon on the lead wire and measuring point to provide stable temperature measurement over long periods.The sensors can be used to measure the temperature of chemicals in medical device manufacturing operations.
RKC Instruments, South Bend, IN
www.rkcinst-usa.com

Medical magnetic sensor

A giant magnetoresistive (GMR) magnetic sensor is designed for use in battery-powered implantable devices such as pacemakers, ICDs, neurostimulators, and drug pumps. Packaged in a four-pin 1.1 × 1.1 × 0.45-mm ultra leadframe land-grid-array leadless package, the BD020 is suitable for wire-bonding assembly. The integrated circuit consists of a GMR sensor element, CMOS signal processing circuitry to convert the analog sensor element output into a digital output, and oscillator and timing circuitry for power-management duty cycling. Configured as a magnetic switch, the sensor produces an output that turns on when a magnetic field is applied and turns off when the field is removed. In addition, the sensors have an integrated latch ensuring that the output is available continuously. The minimum magnetic operate point is 10 Oe. The applied magnetic field can be of either polarity, and the magnetic operate point is stable over supply voltage and temperature. Smaller than reed sensors, these sensors can also provide more magnetic sensitivity and more-precise operate points.
NVE Corp., Eden Prarie, MN
www.nve.com

Digital pressure sensors

Digital pressure sensors perform precise digital signal conditioning, achieving good total accuracies. The HDI series offers absolute, differential, and gauge pressure measurements in various ranges from 10 mbar to 10 bar. The sensors perform unidirectional, bidirectional, or barometric calibrations and are intended for use with air and noncorrosive gases. Optional 3-V supply-voltage versions and special low-power devices make the series suitable for battery-powered applications. Miniature surface-mount-technology housings allow for space-saving PCB mounting and OEM design flexibility. An internal application-specific integrated circuit compensates for sensor offset, temperature effects, and nonlinearity, enabling a total error band better than ±0.5% frequency selective surface. The pressure sensors provide digital interfaces using the I²C bus protocol and analog 0.5–4.5-V output signals.
Sensortechnics, Walpole, MA
www.sensortechnics.com/hdi

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