Passive Rotary Optical Encoder Shrugs Off Harsh Environments

Oct. 18, 2004

No integral electronics can be found within the encoder housing of a novel rotary incremental optical encoder. Micronor's entirely passive MR312 ZapFree encoder has an all-optical design. Thanks to wave-division-multiplexing (WDM) technology, just a single 62.5/125-µm multimode optical fiber connection is required. With WDM, each optical signal path is assigned a specific wavelength over the same single fiber.

The encoder offers immunity to lightning and atmospheric static that would "zap" conventional encoders. It also outdistances copper cabling by allowing link lengths up to 1000 m (3280 ft). Its inert nature suits it for hazardous and explosive environments, and its intrinsic EMI/RFI resistance enables safe and reliable operation in medical equipment and noisy industrial sites.

Two versions are available, one with 100 parts per revolution and the other with 256. The standard operating-temperature range is 40°C to 80°C. An extended temperature-range option covers 60°C to 150°C. The housing is a standard-size 58 package (58-mm outside diameter).

For a turnkey solution, the MR310 remote optical interface is available for standard interfaces. The MR310's outputs are a standard A/B open-collector and a single line-driver quadrature signal.

The MR312 encoder is priced at $635 and the MR310 interface costs $1600, both in 100-unit quantities. For a complete system, users would have to add a 100-ft long commercial-grade optical fiber cable that runs about $100 for installation.

Micronor Inc.www.micronor-inc.com
(805) 499-0114

About the Author

Roger Allan

Roger Allan is an electronics journalism veteran, and served as Electronic Design's Executive Editor for 15 of those years. He has covered just about every technology beat from semiconductors, components, packaging and power devices, to communications, test and measurement, automotive electronics, robotics, medical electronics, military electronics, robotics, and industrial electronics. His specialties include MEMS and nanoelectronics technologies. He is a contributor to the McGraw Hill Annual Encyclopedia of Science and Technology. He is also a Life Senior Member of the IEEE and holds a BSEE from New York University's School of Engineering and Science. Roger has worked for major electronics magazines besides Electronic Design, including the IEEE Spectrum, Electronics, EDN, Electronic Products, and the British New Scientist. He also has working experience in the electronics industry as a design engineer in filters, power supplies and control systems.

After his retirement from Electronic Design Magazine, He has been extensively contributing articles for Penton’s Electronic Design, Power Electronics Technology, Energy Efficiency and Technology (EE&T) and Microwaves RF Magazine, covering all of the aforementioned electronics segments as well as energy efficiency, harvesting and related technologies. He has also contributed articles to other electronics technology magazines worldwide.

He is a “jack of all trades and a master in leading-edge technologies” like MEMS, nanolectronics, autonomous vehicles, artificial intelligence, military electronics, biometrics, implantable medical devices, and energy harvesting and related technologies.