Miniscule Absolute Encoder Cuts Assembly Time In Half

July 21, 2003

This high-speed plug-and-play device, which comes in five resolution options, shaves industrial-automation system costs by 40%.

Roger Allan

A novel absolute encoder module that comes in 12- and 16-bit versions uses a modular approach to reduce the number of assembly steps from as many as eight down to just four (see the figure). Agilent Technologies says that its AEAS-7000 is the world's smallest encoder module, measuring 21.4 mm high by 55 mm in diameter. The module also reduces the number of needed components from approximately 80 down to four.

"We use a combination of precision machining and an ASIC chip that contains the signal-conditioning electronics to realize this plug-and-play capability in a small form factor," says Colin Choo of Agilent. "Just four steps are needed to make the absolute encoder: secure the codewheel, slide the module in, secure the module, and remove the alignment clips."

The encoder consists of 13 signal photodiode channels and a single monitor photodiode channel. It features a synchronous 16-MHz true differential pair of sine/cosine outputs over a four-wire serial interface with 1024 periods for unit alignment, as well as a 1-µs cycle time. It has on-chip interpolation and Gray-code correction within ±1 LSB for mounting-tolerance compensation and is accurate to within 16 bits for motions up to 1000 rpm (12 bits up to 12,000 rpm). Plug-and-play eliminates alignment tweaking and manual searching for the LSB and MSB signals. Five encoder resolution options are possible, between 12 and 16 bits.

The unit targets industrial-automation applications, including servo motors, robotics, machine tools, and wafer handlers. Available in August, pricing is under $28 each in 5000-unit lots.

Agilent Technologieswww.agilent.com

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.