The SFD-M high-resolution encoder offers multi-turn absolute feedback. | Source: Kollmorgen
Kollmorgen Corp., a developer of motion control and automation systems, this week introduced the Smart Feedback Device, Multi-Turn, or SFD-M, encoder. It said the SFD-M allows machine builders to achieve high-resolution, multi-turn feedback with absolute positioning information available at system startup.
“Our new SFD-M encoder provides multi-turn absolute functionality with exceptional position accuracy and resolution at zero additional cost over Kollmorgen motors with single-turn encoders,” said Chris Cooper, senior director of global product management at Kollmorgen.
“That’s a huge benefit for precision and productivity at a savings of hundreds of dollars per motor and potentially several thousand dollars in a complex, multi-axis machine,” he added. “Single motor-to-drive cable technology with auto drive setup further lowers total costs. We are very proud to offer all of these benefits to our customers as an integral part of Kollmorgen’s industry-leading servo systems.”
Designed to work with AKD and AKD2G drives, the SFD-M absolute multi-turn encoder can be integrated into Kollmorgen-housed servo motors. This comes at no additional charge in comparison with the SFD-3 single-turn absolute encoder. This enables it to provide multi-turn performance, four times greater positioning accuracy, and 50 times lower EMF noise.
Kollmorgen has more than 100 years of motion experience. Its extensive product portfolio includes motors, drives, linear actuators, automated guided vehicle (AGV) control systems, and automation control platforms. The Radford, Va.-based company said its technology combines performance, reliability, and ease of use to give machine builders a marketplace advantage.
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SFD-M provides absolute multi-turn positioning
Kollmorgen said the SFD-M is equivalent to other third-party encoders that come with a premium price. With the SFD-M, customers can achieve substantial savings in machine designs that perform at high levels of precision, efficiency, and effectiveness, it asserted.
The SFD-M measures the position of the rotor shaft throughout each 360º rotation without requiring reference to a home position. In addition, it registers the total number of rotations the shaft has made in either direction.
This absolute multi-turn positioning capability is important when precise tracking of position is required over large rotational distances, such as in machine tool positioning, packaging machines, material handling, satellite tracking, and many other applications, said Kollmorgen.
The SFD-M also maintains absolute positioning information in real time, even when the system is powered down, eliminating the need for time-consuming homing sequences upon startup, the company said.
Kollmorgen shares key specifications
Absolute multi-turn encoders from other providers often require a battery to retain positioning information when the system is powered down or during a power failure, noted Kollmorgen. These external batteries require replacement and can be subject to failure. Other alternatives use mechanical gear trains, which are noisy, backlash-prone, and add size to the motor.
The new Kollmorgen SFD-M eliminates these issues, instead using energy-harvesting technology to reliably maintain positioning information with no need for batteries or gear trains. Battery-free operation eliminates maintenance issues while also supporting efforts to reduce the consumption of natural resources and minimize waste.
Kollmorgen said the SFD-M is highly accurate and listed more specifications:
Resolution of 24 bits per revolution
16,777,216 counts per revolution
0.0772 arc-sec per count
Multi-turn absolute range of 16 bits = 65,536 motor revolutions
Accurcy of < +/– 1 arc-min typical at 25ºC an < +/– 3 arc-min worst case
See Kollmorgen at the Robotics Summit & Expo
To learn more about Kollmorgen’s latest products, see it at the 2025 Robotics Summit & Expowhich takes place April 30 to May 1 at the Boston Convention and Exhibition Center. The company will be exhibiting at Booth 644.
In addition, on Thursday at 2:30 PM, Stephen Funk, an electromagnetics design engineer expert at Kollmorgen, will be speak about “How to Select the Right Motor to Reduce Cost and Time to Market.”
His presentation will explore the balance between configuration and customization. Funk will look at the continuum from standard and configurable products, which offer quick solutions, to customization, which provides the flexibility needed for precise optimization. This is particularly important in tailoring motor properties to meet stringent requirements, offering a distinct advantage in robotic applications, according to Funk.
The Robotics Summit also offers numerous networking opportunities, a Career Faira robotics development challengethe RBR50 Robotics Innovation Awards Galaand more.
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