Control Engineering Motors, Drives, & Motion Control Newsletter for March 2001

By Frank Bartos June 4, 2002

In this issue:

  • 1,000,000-th chip for SERCOS
  • Low-cost capacitive position sensing
  • New ergonomic assist devices have intelligence
  • Cheer the young ‘Roboteers’
  • Two motor starters introduced at NMW
  • Online servo selection tool
  • Linear motors market survey is optimistic
  • Conferences, seminars
  • Info free for the asking
  • Control Engineering in March

1,000,000-th chip installed for SERCOS

A ceremony on March 21, 2001 at RA Jones & Co. (Covington, Ky.)-a leading manufacturer of packaging machinery for consumer products companies-marked a notable milestone for SERCOS communication interface when the one millionth SERCOS ASIC was installed on one of RA Jones’ packaging machines.

SERCOS (SErial Realtime COmmunication System) is a fiber-optic-based network expressly designed for motion control applications. SERCOS, defined in IEC 61491 standard, claims more than 100 suppliers of products worldwide that comply with the interface. Applying the SERCOS interface was part of upgrading of the packaging machinery controls ‘to make full use of servos’ says RA Jones.

In a related item, the SERCOS alliance has launched an initiative to bring SERCOS technology down to smaller servo systems (1 kW and under continuous output power), where it has not been cost-effective in the past. Yet, servo drives and motors below 1kW dominate the market with around 70% of the unit volume, according to data supplied by Sanyo Denki of Japan, a major supplier of ac servo systems. Smaller servo drives from SERCOS association members, for example Sanyo Denki and Pacific Scientific, have already been announced with others expected to follow.

George Kaufman, president of SERCOS North America and president of Automation Intelligence (Duluth, Ga.)-a wholly owned company of Sanyo Denki-thinks the new crop smaller SERCOS-compliant drives will add more fuel to the growth of SERCOS technology. He urges ‘machine builders that looked at SERCOS before, but couldn’t justify the larger drive packages or higher cost, to look again.’

SERCOS interface’s benefits are seen in enhanced performance due to its 32-bit commands, availability of more status and diagnostics information, and noise-free fiber-optic wiring.

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Low-cost capacitive position sensing

Do you need low-cost position sensing with up to 18-bit angular resolution or 10s available in linear as well as rotary models.

In the linear encoder version, Netzer Precison’s design applies circuit board production methods to print conductive patterns on the scale and scan head, reducing the encoder’s cost. The scale (transmitter) and the scan head (receiver) interact electrically to produce ‘pure’ sine and cosine dc signals. A combination of coarse/fine output determines absolute position. An incremental version of the device uses only the fine-mode output mode. Reportedly, submicron resolution can be derived from the signals.

Benefits of Electric Encoder include low power consumption, magnetic/EMI immunity, and ‘large’ areas of the transmitter and receiver being active in the sensing at a given time. For more information, contact Netzer Precision at e-mail: ; Tel: +972 4 999 0420. In North America, contact Botec Corp. (Smithtown, N.Y.), Tel: 631/979-7751. e-mail:

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New ergonomic assist devices have intelligence

Cobotics Inc. (Evanston, Ill.) recently announced what it calls a new class of ergonomic devices that can improve productivity and safety in your material handling applications. So-called Intelligent Assist devices (IADs) amplify human ability to guide, lift, and position heavy or difficult-to-move objects with the aid of microcontrollers, servo motors, and an advanced ‘sense/process/actuate’ control concept.

However, IADs are neither robots nor earlier generation power assist or load-balancing devices. IADs from Cobotics (formerly CoMoCo) use patent-pending ‘intent sensors’ to quantify an operator’s intended speed and direction of movement, then process the information virtually immediately, from which proprietary algorithms direct the IAD’s movements, according to the company. ‘This concept relies on closed-loop force feedback to let a person work with a machine in a natural and intuitive manner,’ says Cobotics.

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Cheer the young ‘Roboteers’

One of North America’s largest robotics automation contests for students is just around the corner. On April 7-8, 2001, ‘ The Student Robotic Engineering Challenge ‘ (SREC) takes place at Robert Morris College in Moon Township (Pittsburgh), Pa. Robotics International of the Society of Manufacturing Engineers (Dearborn, Mich.) sponsors the Olympic-style competition for middle school through university-level students.

SREC allows contestants to demonstrate their understanding of manufacturing processes and controls via robotic and automation solutions. The young ‘roboteers’ can choose to compete in over a dozen SREC categories that range from Manufacturing Work Cells and Flexible Manufacturing, to Remote/Self-Controlled Robots and Pick & Place Programming, to Rapid Application Development and Lightweight-Heavyweight Robots-among others. Some 550 students (on 220 teams) from 55 schools in 10 states will participate in the event.

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Two motor starters introduced at NMW

Schneider Electric/Square D (Raleigh, N.C.) used the occasion of the recent National Manufacturing Week (NMW) exhibition to introduce a new generation of TeSys D Line (‘Telemecanique System’) motor starters to North America. D Line features smaller dc contactors, which need 75% less control power than traditional coils, and uses half the panel space. D Line handles motors up to 20 hp at 480 V.

Also introduced at NMW was Baldor Electric ‘s (Fort Smith. Ark.) Digital Soft Start controls for motors in the 3 hp to 700 hp range. Output ratings of the controls are 9 through 900 Amps. An ‘auto-setup’ function in Digital Soft Start’s control software sets the unit for pump/fan, compressor, and conveyor applications. Users enter only operating parameters in plain-English language into a keypad.

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Online servo selection tool

How can you make a fast, first-cut search for a motion control solution from the myriad of servo products offered by just one manufacturer? Product Selector , a web search engine from Kollmorgen (Radford, Va.), claims to do just that job for the company’s ‘vast array’ of servo products. Product Selector searches Kollmorgen’s large database of brushless dc servo motors, direct-drive rotary and linear brushless servo motors, and drive amplifiers.

The search engine only looks at ‘basic attributes’ of motors and amplifiers-for example, torque/force, speed, voltage, current rating, feedback, and dimensions. After an initial choice, Product Selector is used with Kollmorgen’s ‘Motioneering’ dynamic analysis sizing software to account for details of the specific machine’s or motion system’s dynamic requirements.

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Linear motors market survey is optimistic

‘Linear motor market to double in four years,’ says a market survey entitled ‘The European and North American Market for Linear Motors’ published in late-December 2000 by Intex Management Services Ltd. (IMS, Wellingborough, Northants, U.K.; Austin, Tex.).

IMS has sized the 1999 linear motors markets of Europe and North America at $82.6 million, and estimates an annual growth of over 20%, reaching $209.2 million in 2004. Higher acceleration/deceleration and running speeds plus lower cost of ownership, relative to traditional linear motion alternatives, are seen as the market drivers. In North America, contact IMS at Tel: 512/302-1977.

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Conferences, seminars

Seminars, conferences, workshops, etc., can help motion control professionals to keep up to date. Some upcoming events follow.

Galil Motion Control Inc. (Rocklin, Calif.) presents ‘Motion Control Made Easy’ (half day) on April 2 and ‘Advanced Motion Control’ (full day) on April 3 in Boston, Mass. Noted motion control authority and Galil president, Dr. Jacob Tal, will teach these seminars. Tel: 800/377-6329.

‘Working with Servos, plus Motor Basics’ seminars, presented by Bull’s Eye Marketing Inc., Industrial Controls Consulting Div. (Fond du Lac, Wis.), have four upcoming dates:

April 4-6, 2001 (Los Angeles, Calif. area)
April 23-25 (Cincinnati, O. area)
April 25-27 (Cleveland, O. area)
May 16-18 (Chicago, Ill. area)

A four-page brochure is available from Tom Bullock. Tel: 920/929-6544.

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Info free for the asking

Motors, drives, and motion control product suppliers offer another source of valuable information to users. Here is a recent sampling

A new 450-page ‘Linear Motion & Control Solution Guide’ from Thomson Industries Inc. (Port Washington, N.Y.) provides a full picture of the company’s linear guides, stages, slides, systems, and motion control products.

LinMot (Rogers, Minn; Zürich, Switzerland) offers a comprehensive guide to linear motor technology in its ‘2001 Edition Industrial Linear Motor CD.’ The disk contains LinMot’s entire technical library, including manuals, applications, and analysis software. Tel: 877/546-3270.

‘Fundamentals of Polyphase Electric Motors’ is a handy reference for user of these common industrial motors, including the ac induction motor. The 12-page brochure is published by Lincoln Motors (Cleveland, Ohio).

A new catalog on ‘Motor and Generator Protection’ from Meg Alert (Minacqua, Wis.) overviews such topics as plant safety improvement, motor/generator failure prevention, and how to incorporate test methods for these equipment in a preventive maintenance program. Meg Alert manufactures testing and protection systems for electric motors and engine-generator sets.

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Control Engineering in March

My article on ‘ Sensorless AC Drives ‘ updates developments in ac adjustable-speed drives that work without encoder feedback. These drives fill a gap between simple Volts/Hertz control and closed-loop flux vector control of electric motors. An Online Extra article adds further coverage to the topic.

In the News section, our preview of Hannover Fair (April 23-28) includes newsworthy items on drives and motion control. Lynn Electronics Corp’s (Charlotte, N.C.) Quadrater Encoder Tester product has a complete run on pp. 30, 32.

Don’t to miss five ‘best products of 2000′ in motors, drives & motion control -among 35 others in Control Engineering’s overall coverage. It’s part of our annual Editors’ Choice Awards article and presentation ceremony held on the eve of the NMW exhibition.

In the Products & Software section, see magnetic synchronous torque-limiting clutches that transmit torque through a barrier from Rimtec Corp. (Addison, Ill) and Pittman’s (Harleysville, Pa.) line of brushless dc motors with commutation electronics housed inside the motor structure.

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