DN Staff

January 7, 2002

5 Min Read
Innovative Sensor Products

To help readers get information more quickly, a new service debuts in this issue. Simply key in the URLs listed below and go directly to detailed product information on the vendor's website. Change only the last three digits of the URL to research the other products listed.

Sensor cuts power consumption

Low power and temperature-conversion speed are key attributes of Analog Devices' AD7414/15 temperature monitoring system in a compact SOT-23 package. The AD7414 (6-pin lead version) and AD7415 (5-pin) contain a band-gap temperature sensor and 10-bit analog/digital converter to monitor and digitize readings to a resolution of 0.25C. Measurable temperature range is -55 to 125C with plus or minus 2C accuracy. Claire O'Keeffe, marketing engineer, stresses the low power consumption, listed as less than 3 muW, "orders of magnitude" below competing devices. "The fast conversion rate of 40 microseconds, as opposed to upwards of 1 second, is due to the SAR (successive approximation register) architecture. With shorter conversion time, you don't wait long to get a reading," which consumes power, producing heat. A one-shot mode further saves power by allowing an operation to power up for a single conversion, and then power down. "Battery equipment lifetime can be improved by upwards of 30 times," notes O'Keeffe.

Analog Devices: Enter 623 or go to www1.uts.com/DN/URS.1.1.101

Level sensor boasts accuracy, simplicity

George Fischer Inc. has introduced the +GF+ SIGNET 2222 Magnetostrictive Level Sensor for continuous measurement. The slim body features a 5/8-inch NEMA 6/IP68 tube that houses the sensor electronics, eliminating bulky enclosures. With a simple float and magnetostrictive microprocessor-based technology, the 2222 delivers accuracy of plus or minus 0.1% of full scale with 0.01-inch resolution. Applications Engineer Marc Cartier notes the sensor's precision, "A high-current pulse is induced into a magnetostrictive wire within the sensor body. The permanent magnetic field within the float causes a strain in the wire. A strain pulse is returned in both directions along the wire. The time difference between reflected pulses determines the float's position." The 2222 comes in a stainless-steel or PVDF body and is suited for non-coating liquids, such as water, acids, bases, and corrosives. Output is either 4-20 mA or the SIGNET Sensor Serial Link.

George Fischer Inc.: Enter 624, or go to www1.uts.com/DN/URS.1.1.102

Positioning goes field programmable

The Temposonics(R) R Series AQB quadrature interface position sensor from MTS Systems Corp. Sensors Div. is field programmable. Via an RS-232 link, a user can fix the pulse frequency, resolution (from 50 to 12,500 counts/inch), and polarity (direction), according to Dave Edeal, engineer and technical marketing manager. "It represents a migration from separate devices to integrated device intelligence, converting from conditioned output to an output of choice," he says. With such sensor intelligence (as setting the pulse width to a particular controller), no interface module between the sensor and controller is needed, adds Edeal, cutting inventory costs. The magnetostrictive-based device can function as an incremental sensor but retains absolute sensor capability such as during startup, or on-demand position verification without the need to "rehome," as with an encoder. Pulse frequency can range from 8 kHz to 1 MHz and the sensors come in rod- and profile-styles.

MTS Systems: Enter 625 or go to www1.uts.com/DN/URS.1.1.103

Laser system detects small targets

Finding a 1-mm target at a distance of 700 mm is possible with Omron Electronics' F3C-AL laser sensor. Product Manager Dave Grimmett says the sensor's low hysteresis allows such accurate sensing across its 150- to 700-mm range. He adds that the device's electronic receiving elements, processing algorithms, and triangulated optics result in a small black/white error-which eliminates resetting parameters or changing sensors when changing colors, materials, or sensor inclination. The visible red laser spot also facilitates target alignment. Other features include narrow housings for the optics (8 mm) and body (18 mm), and auto power control to boost power if the sensor lens gets dirty. Applications include assembly automation, electronics, machine tool breakage monitoring, materials handling, and packaging. The F3C-AL costs $375.

Omron Electronics: Enter 626 or go to www1.uts.com/DN/URS.1.1.104

Hall effect gives transducer accuracy

Rather than use shunt resistors or current transformers, which produce excessive heat and increase weight, compact DIN-rail MCR-S ac/dc current transducers from Phoenix Contact use a Hall effect sensor, according to Instrumentation Product Specialist Davis Mathews. Another advantage, he adds, is the sensor output can be microprocessor programmed, thus serving as a process variable for monitoring by a PLC. "Since the low-level millivolt sensor signal is susceptible to noise, you have to eliminate error signals on the output," Mathews notes. This is done by three-way isolation between input, output, and power supply, allowing high-accuracy measurements. The 0-11A version of the MCR-S accepts direct termination of the current signal wires, while the 0-55A model accepts the current carrying conductor (up to 10.5-mm diameter) passed through the center of the module's 22.5-mm housing. There are 12 choices of current and voltage outputs.

Phoenix Contact: Enter 627, or go to www1.uts.com/DN/URS.1.1.105

Photo ICs integrated into compact package

The S8030 and S8064 photo ICs from Hamamatsu Corp. integrate a photodiode, LED driver, and signal processing circuitry into a subminiature package for proximity detection. With a photodiode peak sensitivity wavelength of 850 nm, the devices are designed for use with an infrared LED and light emitting and receiving lenses. The dual photodiode has a 0.7- x 0.5-mm active area per channel, and an optical triangulation measurement cycle is used to detect distance to an object out to several meters, according to engineer Kenneth Kaufmann. LED strength, optics, and object reflectivity will affect the actual range, he adds. Accuracy is aided by a dark housing, including the photodiode window, and a synchronous optical detector, which make the photo ICs immune to background light. A photo sensitivity of 0.3 A/W gives suitability for high-speed optical switches, in addition to robotics applications and light curtains.

Hamamatsu Corp: Enter 628, or go to http://www1.uts.com/DN/URS.1.1.106

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