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Absolute Single and Multiturn Encoders
Fully optical multiturn encoder eliminates use of gears and magnetic sensors
Al Presher, Contributing Editor -- Design News, September 10, 2009
A
new family of Sendix F36 singleturn and multiturn optical encoders from Kuebler
GmbH implements an OptoASIC and new scanning capabilities to boost absolute
encoder performance. Intelligent Scan TechnologyTM is key to what
the company says is the first fully optical, absolute multi-turn encoder that
doesn't utilize mechanical gears or magnetic sensors.
The ASIC used in the design is able to monitor position without using gears to mechanically drive the code disks, or magnetic sensors to count the rotations and calculate the position of the encoder. Eliminating the gears helped streamline the diameter of the encoder and reduce costs by as much as 15 percent.
The multi-turn version has a resolution of up to 41 bits, and can track up to 16 million revolutions. Precision optical sensors used in the single-turn absolute encoder offers a resolution of up to 17 bits.
Eliminating mechanical parts improves performance, reliability and has allowed Kuebler to make the encoder smaller than others currently on the market. Hollow shaft diameters are available up to 10 mm, even though the diameter of the flange housing is only 36 mm.
The sturdy bearing structure of the unit's Safety LockTM design accounts for two-thirds of the total depth of the encoder, and allows for use of larger bearings with longer life and better resilience. Two bearings are interlocked together with the housing and spaced apart to redistribute stresses created by shaft loading. The radial load capacity is 40N and the axial load is rated at 31N at the end of the shaft.
A key to the product is the number of available options, and the ability to specify either shafted or hollow shaft designs. The F36 absolute encoder is offered in both metric and English shaft sizes, and standard interface options including SSI/BiSS and CANopen. Additional incremental outputs, SinCos or RS 422, supply the system with high resolution feedback in real time.
From right to left: Doug Robertson, Design News; Tony Udelhoven, director, TURCK Sensor Div.; and Dave Lagerstrom, president & CEO TURCK U.S.
