bullet On-line Magazine 'Sensors & Transducers' (S&T e-Digest)

    (ISSN 1726- 5479)


No. 2, February 2003



Table of Contents




Compact Highly Accurate Filling Level Sensor


The new magnetostrictive highly accurate level sensor TORRIX of FAFNIR GmbH supplies information on tank levels. Through its continuous filling level measurement it  creates quality assurance and safety during the process. TORRIX is suitable for all liquid media for which a  highly accurate level measurement is required.


The advantages at a stroke

  • Application in ex-zone O (ATEX certificate)

  • Resolution better 0,1 mm

  • Measurement processing controlled by µController

  • Temperature-compensated measuring principle

  • 2-wire terminal (4-20 mA)

  • Very short measuring intervals

  • Durability due to robust structure

  • Shock and vibration-proof

  • Measuring range along the complete sensor length by 2 function keys adjustable

  • Very simple installation and starting


The sensor operates according to the magnetostrictive measuring process. A wire of magnetostrictive material is integrated into the probe tube. By means of the micro-controlled sensor electronics electrical impulses are sent through the wire creating a circular magnetic field. A magnet is built into the float which magnetizes the wire at the float position. On the location of the superposition of the two magnetic fields a torsion wave is generated which spreads along the wire to the sensor head.  The propagation time is registered and processed by the electronics.



The highly accurate filling level sensor TORRIX is basically produced at the standard stainless steel version. But it could also be made of other special materials such as Hastelloy C or B. The sensor can be delivered with screw-in unit or flange. The screw-in unit dimensions 1/2" or 1 1/2" are also available for a 12 mm probe tube diameter.


Mrs. Sofia Heidecker,


Bahrenfelder Str. 19

22765 Hamburg, Germany

Tel: +49 / 40 / 39 82 07-52

E-mail: info@fafnir.de

Filling Level Sensor TORRIX





100 mV/g Triaxial Industrial Accelerometer

Model 629M06 Triaxial Industrial Accelerometer from IMI Sensors, a division of PCB Piezotronics, Inc., provides the convenience of triaxial vibration measurements for monitoring the health of rotating machinery. The small, 1-1/8 inch cube is handy for portable, data collection yet durable to withstand tough, permanent installations. A stainless steel housing, with four-pin military style connector and 250 °F operating temperature range, stands up to the rigors of harsh industrial environments. Additional features include 100 mV/g sensitivity, 48 to 720k cpm frequency range, electrical case isolation, 560 ug resolution, and NIST traceable calibration. The sensor is ideal for predictive maintenance and condition based monitoring of bearings, gears, motors, pumps, and compressors.


Eric G. Yax

IMI Sensors,

Sales Manager

IMI Sensors Division

Fax: (716)684-3823

E-mail: eyax@pcb.com

629M06 Triaxial Industrial Accelerometer



Compact Torque Transducer Transmits Signals via Digital Telemetry

The Force/Torque Division of PCB Piezotronics, Inc., announces the release of a new series to the Torkdisc®, family of low profile, high-stiffness, rotary torque transducers. Series 5302 offers the same advantages as all other Torkdisc® models, which utilize rugged, strain-gage sensing technology and wireless, digital, signal telemetry to transmit measurement signals to an adjacent receiver. Additional features include compact design, low weight, low rotating inertia, RF interference immunity, and low sensitivity to axial thrust and bending moments. The thin, low profile configuration requires minimal space for mounting, a plus for cramped installation situations. The Series 5302 sensor is offered in a 7 inch diameter flange and a choice of capacities from 1000 in-lb to 6200 in-lb FS and represents an ideal, state-of-the-art solution for demanding dynamometer applications.

Peter Munschauer,

Division Manager

Force/Torque Divison

Tel: (888) 684-0004

Fax: (716)684-8877

E-mail: pmunschauer@pcb.com

Rotary torque transducer 5302 Torkdisk



Digital Readout Wood Moisture Meter

Delmhorst Instrument J-2000 Wood Moisture Meter

Delmhorst Instrument J-2000 6-40% Digital Readout Wood Moisture Meter is used by quality control inspectors, lumber buyers, hardwood flooring installers and manufacturers, pest control services, painting and general contractors, furniture and cabinetmakers and woodworkers. Analyze wood surface and core moisture content in all mill and woodworking applications. Features a newly designed functional case with a built-in handle that puts controls at your finger tips. It makes one-hand operation fast and easy. Calibrated for Douglas Fir at 70 degrees F., correction charts and/or built-in correction is supplied for other species. Temperature correction charts and/or built-in correction and slide rule are also supplied. Includes batteries, carrying case, and extra set of pins.

Fig. 1 J-2000


"I have found this tool to be very accurate. The ability to specify the wood (I.E.-ash, redoak, etc.) makes this tool more accurate. Because you have to enter the code for a particular type of wood you must have the manual handy, unless you limit yourself to a few types and just memorize what you need. It fits the hand or pocket for portability when you go out to buy wood ", said a customer.


The main features of digital readout wood moisture meter J-2000 are the following: microcontroller circuit and LCD display; corrects for 48 individual species and temperature (F and C); measures moisture content over the range of 6-40% averages up to 100 accumulated readings; one-year warranty. This model is popular among woodworkers, small shops, and furniture manufacturers. If you prefer a popular analog or LED readout, the J-4 and J-LITE models are available. Both have 6-30 % moisture content range and reduced prices.


Delmhorst Instrument 26-ES Wood Moisture Meter Remote Electrode is the very useful accessory for J-2000, J-lite, and J-4  moisture meters. The standard steel contact pins, #496, have insulated shanks so that moisture content is measured only at the points, which are not insulated. The uninsulated tip area for measurement is approximately 3/16 in. Use the sliding hammer action to quickly measure moisture at various levels of penetration. This is a sure way to identify a moisture gradient without cutting the wood. Maximum penetration of the #496 pins is 1-1/8 in. They can be used on softwoods and on hardwoods from 1/8 in. to 5 in.. thick or 6 in. diameter. The main performances are: measurement of a moisture gradient; test dry lumber; 10 inch solid steel shaft.


For more information and prices please see e-Shop.



New Kit Reads and Writes TEDS Information to Sensors


PCB Piezotronics, Inc. and The Modal Shop, Inc. (A PCB Group Co.) have jointly released Model 400A76 TEDS Sensor Interface Kit. This kit provides the hardware and software required to interface with more TEDS sensors than any previously-available software interface. Operating on a Windows PC via an RS-232 port. Model 400A76 kit enables the user to read and write TEDS data in 16 IEEE TEDS templates and three templates established by LMS International.


Types of transducers supported include accelerometers, microphones, charge amplifiers, and microphone preamplifiers. Model 400A76 kit consists of a 100-7158-20 RS-232 Hardware Interface Dongle, TEDS Read/Write software, and a cable assembly.


This kit represents one of the most advanced implementations yet of IEEE P 1451.4, a developing standard for mixed-mode TEDS sensors. This new software is powered by The Modal Shop's latest TEDS encoding/decoding engine, enabling read/write access to sensors with 256 bits of memory.


Bill Andrews,

Division Manager

PCB Electronics Division

Tel: (800) 828-8840

Fax: (716)684-0987

E-mail: bandrews@pcb.com



Fast Response Digital Motor Load Controls


A new series of fast motor load controls designed specifically to monitor and protect valuable industrial machinery and equipment has been released by sensing specialist Vydas International Marketing. The New Fast Response Digital Motor Load Control manufactured by Load Controls Inc (USA) monitors true motor power and detects common machinery problems such overloads, jams, obstructions, loss of load, sudden load changes, missing tools or misplaced parts.


The PFR-1550 single set point control, with high or low trip, detects overload or loss of load while PFR-1750 two set point control can trip an alarm and stop the machine with independent relay outputs. The ROC-50 rate of change control is ideal for use with conveyers and material handling equipment and detects sudden changes in load. This sensor has a rate of change set point plus gross overload. The model CR-150 single point current sensor is also available for special circumstances where it is required to measure current gross overload only. All models have a 4-20mA output to send load information to instrumentation, computers, chart recorders or data logger's etc. In order to avoid the possibility of nuisance trips during use or at motor start up, all models also have adjustable digital start up and trip timers. These sensors are housed in a compact rugged polycarbonate waterproof enclosure, with large digital display (HP or KW) plus keypad and can be mounted on a door, inside a control cabinet or surface panel mounted with included bezel kit. Settings can easily be seen on the digital display at the touch of a button. Electrical connections are made via convenient plug and socket terminal strips on the rear of the unit. A unique range finder toroid is included to allowing fast easy set up of motors up to 50HP connected directly. Larger motors require optional current transformers to be used in conjunction with the range finder toroid.


This product range is designed to cope with the most difficult of motor load sensing tasks when other power sensors and motor load controls are unable to function reliably. The control and reliability of many process machines such as grinders, mills, mixers, rollers, pumps, compressors, conveyers etc may be improved dramatically by sensing true power instead of only current thus saving down time and loss of production. In practice, it doesn't matter however sophisticated the control computer system, its overall system performance is very much dependant on the sensors at the front end.


Measuring power on the output of variable frequency drives is a special case, as voltage and current transformers do not work at low or high frequencies. In this case, waveforms on both the input and output of a  drive, are distorted and will cause gross errors in the measurement of power. Where variable frequency or inverter drives are fitted the "V" Series Fast Response Motor Load Controls should be used in conjunction with the unique Universal Power Cell designed for this purpose. The UPC is fitted with "Hall Effect" sensors that are not affected by odd wave shapes or frequencies.


Cliff Wyatt,

Vydas International Marketing,

Telephone: 44 (0)1428 751822 

Fax: 44 (0)1428 751833

E-mail: info@vydas.co.uk





Modeling MEMS and NEMS

by John A. Pelesko, David H. Bernstein


In this new book devoted to MEMS and NEMS modeling published at the end of 2002 authors bring you up to speed on the latest advances in MEMS. "This is among the finest books for modeling MEMS. Most other books give a mish-mash of fabrication and modeling, but you never figure out how to model!! This one is different. This is the gold standard for MEMS books to come.. I picked it up along with many other MEMS books from the library, never thought I would use it, but this is the ONLY book I use. Good even for the the advanced MEMS designer as a quick reference. But great for a new reader who wants to grasp the fundamental of modeling", said a reader.


The book has well structured contents including numerical methods for continuum mechanics, thermally driven systems, elastic structures, thermal- and electrostatic-elastic systems, magnetic actuation, microfluidic devices and much more. Every chapters are supplemented by exercises and contains related reading and notes sections.


For more information and book order please click <here>.

ISBN: 1584883065

Title: Modeling MEMS and NEMS

Authors: John A. Pelesko, David H. Bernstein

Publisher: CRC Press

Pubdate: November 26, 2002

BindingHardcover, 376 pages

Price $US 69.96

Modeling MEMS and NEMS book cover




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