Harmony sought in software for motion-control systems
Leading manufacturers of motion-control and drive products are trying to agree on a common system of digital communications for their products. Meanwhile, many designers and users of robotics are unsure which system to follow. The National Institute of Standards and Technology (NIST) called both camps together for two days in mid-December to thrash out the matter. Most discussion centered on two communications choices: SERCOS and MACRO. SERCOS is the original fiber-optic control network that uses a digital interface between the controller and drives. Developed in 1987 in Germany, SERCOS got a big boost in 1995 when General Motors Powertrain Division decided to deploy it throughout its Pontiac, MI, plant. Chief drawback of SERCOS could be that its current ring speed is only 4 Mbit/- sec. On the other hand, MACRO, a new system that builds on cutting-edge office networking, boasts a data rate of 120 Mbit/sec, fast enough to close servo loops across the ring. Dimitri S. Dimitri, president of Delta Tau Data Systems, Inc., of Northridge, CA, champions MACRO. However, he told Design News he will pursue an idea presented at the meeting for creating software drivers so MACRO can work with SERCOS systems. NIST officials agreed to hold another such workshop in a few months. Until then, the market may help point the way to a de facto communications standard.
Workshop to explore standards for health, safety management
First came the ISO 9000 standards for quality management. Arriving this year will be ISO 14000 standards for environmental management. Should there also be international guidelines for management of health and safety? The question will be tackled at a workshop called by the American National Standards Institute (ANSI) May 7-8 in Rosemont, IL. A task group will use information and opinions gathered at the sessions to help form a U.S. position on the subject. The task group will represent industry, labor, government, insurers, and standards-developing organiza- tions. ANSI will present its viewpoint at a workshop of the International Organization for Standardization (ISO) scheduled for September in Geneva.
Guide highlights EU activities in setting of standards
A new government publication is crammed with facts about harmonization activities in the European Union. It should be useful to designers, manufacturers, and exporters aiming at European markets. Included are lists of EU New Approach Directives, NIST standards-related publications, sources for standards in the United States and Europe, and information contacts. You can get NIST Special Publication 891, "Standards Setting in the European Union--Standards Organizations and Officials in EU Standards Activities," from the U.S. Government Printing Office, Washington, DC 20402. The price is $5 prepaid. Order stock no. 003-003- 03369-3.
Machine measures distances only five atoms long
NIST engineers are developing a machine to help meet the demand for standards in high-tech industries that build products requiring ever tinier precision. Called the molecular measuring machine, or M-cubed, the device has a range 250,000 times wider than that of most scanning tunneling microscopes. The range of a typical STM is about 0.1 mm. M-cubed is expected to measure an area slightly smaller than a dollar bill folded in half to within 1 nm--or the equivalent of a string of about four or five silicon atoms. That's akin to being able to locate two widely separated grains of sand in a 960-square mile patch of desert and then measure the distance between them to within 1 mm, NIST officials say. Still being refined, M-cubed already has made some impressive measurements. NIST plans to use it to calibrate a variety of references manufacturers can use to check the accuracy of their own measurement tools.
EMC regulations now mandatory throughout European Union
Almost all electrical equipment entering the 15-member European Union (EU) must now meet EMC Directive 89/336/EEC. The regulations became mand- atory on January 1. The directive forbids products to generate harmful emissions. Further, they must be immune to electromagnetic disturbances from sources such as telecommunications, radios, and nearby equipment that might malfunction. Manufacturers or importers who fail to comply are subject to fines and imprisonment. EU officials published the EMC directive in 1989. A transition period spread from Jan. 1, 1992, to Dec. 31, 1995. They figured that was enough time for designers to adapt products to meet the directive and avoid costly shielding and retrofitting. The EMC regulations join an EU directive on telecommunications terminal equipment in force since January '92, and directives on machinery, medical equipment, and satellites which have required CE marking since January '95. Later this year EU probably will begin enforcing a directive on automobiles. On Jan. 1, 1997, a low-voltage directive takes effect.