Focus on Magnetics

September 2005, page 68

NMR Spectrometer

Bruker BioSpin has announced the Avance II NMR Spectrometer series that incorporates second-generation digital receiver (2G-DR) technology for improved NMR detection fidelity. Compared with the earlier version, the new technology offers digital resolution more than four times as high and unsurpassed dynamic range; faster digitization rates; an order-of-magnitude increase in oversampling speed and in digital quadrature detection; more than an order-of-magnitude increase in digital filtering bandwidth; and a single receiver for liquids and solids, and for imaging applications. The 2G-DR technology will be beneficial for demanding NMR experiments in solid-state research, synthetic polymer and trace analysis, and magnetic resonance imaging and structural biology, especially when used with the company's highest sensitivity CryoProbes. Bruker BioSpin Corp, 15 Fortune Drive, Manning Park, Billerica, MA 01821, http://www.bruker-biospin.com

2D Magnetic Field Analysis

Integrated Engineering Software has released MAGNETO 6.2, the latest version of the company's magnetic field solver software. It combines the strengths of the boundary element and finite element methods for faster and more accurate solutions. It also features quadratic and angular periodic finite elements. As with earlier versions, MAGNETO 6.2 offers advanced modeling techniques that link directly to parametric-based CAD packages for the true geometric representation of complex shapes. The program is used for applications such as clutches, solenoids, motors, sensors, transformers, loudspeakers, magnetic shielding, circuit breakers, and fuel injectors. The software's calculations include force, torque, flux linkage, and inductance. Integrated Engineering Software, 220-1821 Wellington Avenue, Winnipeg, MB, Canada R3H 0G4, http://www.integratedsoft.com

Miniature Cryogen-Free Magnet

Cryogenic Ltd has developed a miniature cryogen-free magnet with a field of 2.5 tesla and a warm bore workspace of 51 mm. The overall dimensions of the cryostat are 258 mm ×224 mm × 540 mm. The system uses a 1-kW single-phase air-cooled compressor to provide 4.2 K with a cooling power of 0.1 W and 3 W at 50 K; it can be operated at temperatures below 4.2 K. A uniformity of 5 ppm over a 10-mm-diameter spherical volume has made it possible to use the magnet for ESR (electron spin resonance) and low-field NMR experiments. It is thought to be the smallest superconducting NMR magnet yet built. The magnet has its current set at 30 A and can be operated with the current permanently in the leads. The heat load from the leads is about 1.5 W, or in persistent mode, the current decays at 10^–5 per hour. Cryogenic Ltd, Units 29/30, Acton Park Industrial Estate, London W3 7QE, UK, http://www.cryogenic.co.uk

Rotary Encoder IC

The AS5045 absolute analog magnetic rotary encoder integrated circuit from Austriamicrosystems USA has a 12-bit resolution at speeds below 1000 rpm, but operates at higher speeds with reduced resolution. The device provides absolute angle information in a digital format and targets motion-sensing applications that require a resolution below 0.1° of angle. The user can continuously access a serial digital output and pulse-width-modulated (PWM) output at the same time. The angular-position information is in the form of a serial data stream and as a PWM signal with a resolution of 4096 positions per revolution. The model AS5045 has zero-position setting and diagnostic features that are both user-programmable, and the option to cascade several devices in a daisy-chain con_1figuration. Austriamicrosystems USA Inc, Suite 400, 8601 Six Forks Road, Raleigh, NC 27615, http://www.austriamicrosystems.com

NMR Precision Teslameter

GMW Associates has introduced the Metrolab PT 2026, an NMR precision teslameter that uses solid-sample proton probes to measure magnetic fields of up to 20 T, with a field range of up to 10:1. Fully digital signal processing supports two channels that can be used as a 2:1 multiplexer or for simultaneous measurements at up to 60 measurements per second. The new magnetometer features a resolution of ±0.01 ppm, a relative accuracy of better than ±0.1 ppm, and automatic tracking over 100% of the probe range at a maximum rate of 4% per second. Its trigger input allows precise synchronization, and reference frequency and NMR signal outputs allow access to analog signals. The probes can operate in fields with inhomogeneities of up to 4000 ppm/cm. USB and Ethernet interfaces enable local or remote measurement for ramping, stability, mapping, and calibration applications. GMW Associates, 955 Industrial Road, San Carlos, CA 94070, http://www.gmw.com

Electric and Magnetic Field Probes

AR Worldwide's new line of field-monitoring products includes a laser-powered E-field probe (model FL7004), a field monitor (model FM7004), and six battery-powered E or H field probes. The FL7004 laser probe is exceptionally small, with a sphere that measures slightly more than one inch. Its unique antenna design performs better in the presence of harmonic distortion and allows for better isotropic response, free from spikes and glitches. Noise reduction and temperature compensation enable extremely accurate low-field readings, down to 0.5 V/m or better. The six field probes cover the frequency range from 100 kHz to 60 GHz. One of the probes (model FP7050) can read radar pulses. The field monitor works with either laser or battery-powered probes. AR Worldwide, 160 School House Road, Souderton, PA 18964-9990, http://www.ar-worldwide.com

Attitude and Heading Reference System

Crossbow Technology offers its MEMS-based AHRS500GA attitude and heading reference system with the CRM500GA remote magnetometer option for those aircraft applications in which it is beneficial to have the magnetometer separated from the main unit. The AHRS500GA is a truly independent device, meaning that there is no need for Air Data or GPS inputs. Its highly reliable inertial system operates with static and dynamic accuracy that is reportedly superior to spinning-mass vertical and directional gyros. The CMR500GA, a three-axis strap-down

magnetic-field measurement system, uses high-resolution fluxgate sensors and outputs data for three axes of magnetic-field and built-in test status. It is FAA certified for TSO C6d with the AHRS500GA. Crossbow Technology Inc, 4145 North First Street, San Jose, CA 95134, http://www.xbow.com

Superconducting Magneto-optic System

American Magnetics Inc has introduced the Opti-Maxes superconducting vector magnet system. The company's conventional Maxes product can rotate the magnetic field vector on the three principal axes at low temperature without complicated sample manipulators. Through a virtual interface, the user can enter the desired field vector of a three-axis magnet in Cartesian, cylindrical, or spherical coordinates. The Opti-Maxes system offers optical access in x, y, and z planes along with the rotating field and incorporates three split-coil magnets that are fed by three independent four-quadrant power supplies. The standard design allows a 1-T rotational field and an independent field of 4 T, in either a vertical or horizontal geometry. American Magnetics Inc, P.O. Box 2509, 112 Flint Road, Oak Ridge, TN 37831-2509, http://www.americanmagnetics.com

Instructional CDs Using Animation

Square Info Ltd develops and distributes 3D scientific animations designed to bring textbooks and traditional teaching materials to students, electrical apprentices, and electrical trainees. The animations allow lecturers to add visual emphasis to the topics being studied, give students the capacity to visualize scientific concepts in simulated motion, and reinforce the imagery most commonly used in existing reference publications and lecture notes. As an example, CD-ROM 2, titled Magnetism and Electromagnetism, covers 19 topics, each running for 65–124 seconds, that include magnetic repulsion and attraction, ferromagnetic and nonferromagnetic material in a magnetic field, Faraday's law, and the AC generator. See the photo for a static screenshot from animation. Square Info Ltd, Unit 13, Drom Oir, Western Distributor Road, Galway, Ireland, http://www.squareinfo.ie

Hall-Effect Angle Sensor

IC-Haus has announced the iC-MA, a CMOS-device, general-purpose magnetic angle encoder. It consists of a quadruple Hall sensor array that has been optimized for the magnetic measurement of angles of rotation. The user can choose from 26 operational modes for evaluating the angular position of the rotary magnet mounted over the chip. The integrated signal-conditioning unit provides a differential sine/cosine signal at the output. The sensor generates one sine cycle for each full rotation of the magnet, which enables the angle to be clearly determined with the aid of an 8-bit sine-to-digital converter. An incremental interface provides an output in a number of selectable resolutions. The maximum resolution of 8 bits is maintained up to rotations of 60 000 rpm. Used with a permanent magnet, the iC-MA can act as an encoder system with an integrated magnetic scanning feature. IC-Haus Corp, 1609 Foxhorn Court, Naperville, IL 60563, http://www.ichaus.com

Motor Driver

AllMotion has released its EZSV10 DC brush servo driver and controller, a compact unit (24 mm × 35 mm ×15.2 mm) capable of standalone operation. Incorporating an onboard EEPROM for user program storage, it can be set to execute a string of commands on power-up. The user can also issue commands from a serial port or from the Microsoft Windows EZServo/Stepper application. A single four-wire bus can daisy-chain up to 16 DC motors simultaneously. The EZSV10 can control motors at 1.5 A continuous (2-A peak) and 12–40 V, and has position, velocity, and torque modes; quadrature encoder-based feedback; programmable ramps and speeds; switch-selectable device address; and software-selectable maximum currents. AllMotion Inc, 5501 Del Oro Court, San Jose, CA 95124, http://www.allmotion.com

Motorized Positioning Stage

The SQ-2115 closed-loop motorized positioning stage from New Scale Technologies provides five newtons of force in a thin, 17-mm profile. The stage contains an integral optical encoder and a piezoelectric SQUIGGLE motor, which supports vertical loads of up to 0.5 kg with negligible heating and can hold its position in power-off mode. The SQ-2115 is designed for automated nanopositioning in research and industrial instruments. It is ideal in tight spaces, including microscope stages and vacuum chambers; a high-vacuum-compatible option is available. The SQ-2115 stages are easily assembled into two- and three-axis precision positioning systems. The company's SQ-3300 controller can drive up to three motorized stages. New Scale Technologies Inc, 10 East Main Street, Suite 301, Victor, NY 14564, http://www.newscaletech.com

Motor Controller

AmpFlow has announced a microcontroller-based motor controller that supplies up to 180 A per channel at 12–40 V. It features multiple-command input modes for use with radio control receivers, serial ports, or analog devices such as industrial or gaming joysticks. It has two power-output stages with dual H-bridges for full forward and reverse operation of two separate motors. The two channels can be operated independently or mixed for "tank style" steering. A single-channel version is available with twice the rated current. The motors may be operated in open- or closed-loop speed mode and, with position sensors, may operate as position servos. The controller features automatic stop in case of command loss, safe power-on-start, and overcurrent and overheat protection. AmpFlow Inc, c/o Powerhouse, 1540 Winding Way, Belmont, CA 94002, http://www.ampflow.com

Nanopositioning Stages

Physik Instrumente's P-620 series of miniature nanopositioning stages have travel ranges to 600 µm (1 mm custom), and absolute measuring direct-metrology position sensors that provide linearity to 99.9% and subnanometer resolution. Designed for high-duty cycle applications, the stages incorporate a flexure guiding system that is friction-free, long-life ceramic-encapsulated piezo drives, and optional digital control with automatic calibration and tracking-error elimination. Digital controllers (32-bit) with dynamic linearization algorithms improve scanning linearity by three orders of magnitude and provide fast communication and highly stable position control. Systems are offered in x, x-y, z, and x-y-z versions. Physik Instrumente LP, 16 Albert Street, Auburn, MA 01501, http://www.pi-usa.us

New Literature

The new Fluke Precision Measurement catalog contains 256 pages of information about the company's electrical and temperature calibrators and standards, signal sources, time and frequency standards, data loggers, software, services, and support programs. Fluke Corp, P.O. Box 9090, Everett, WA 98206, http://www.fluke.com

The new Directory of Metals and Materials, available from Goodfellow, includes information about pure metals, alloys, polymers, ceramics, and composites, in an extremely wide range of forms and sizes. The directory contains data on physical, thermal, electrical, and mechanical properties. Goodfellow Corp, 237 Lancaster Avenue, Suite 252, Devon, PA 19333-1594, http://www.goodfellow.com

On the Web

Proton Energy Systems has launched a website that offers product information and calculating tools through an intuitive user interface. The tools allow the user to estimate the economic and process benefits of making hydrogen on site with the company's HOGEN hydrogen generators. Proton Energy Systems, 10 Technology Drive, Wallingford, CT 06492, http://www.protonenergy.com