As encoders are used outside of the classic factory automation and machinery building industries, the market has had an uptick in demand and expectations.
Medical equipment and handling machines are among the many industries seeking low cost absolute systems with reduced performance – resolution up to 13-bit, accuracy of only 10-bit.
According to Christian Fell, general manager of FRABA, low cost encoders are often based on magnetic technology and come in smaller packages than the classical optical encoders.
Heavy duty encoders, such as those used in the burgeoning wind power industry or the mobile equipment and truck industry, are in demand for use in harsh environments (water, dust, shaft load).
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“Depending on the required application resolution and accuracy, special designs based on magnetic as well as optical sensing can be used [in harsh environments],” says Fell.
Incremental Shift
Encoders in general will never be obsolete since positioning tasks will always be a main part of the automation and machine building industry.
“Over the last few years, there has been a shift from incremental to absolute encoders,” says Fell. “Since the price difference is becoming smaller and smaller, engineers prefer to implement the advantages of absolute technology. There has also been some shift from standalone encoders towards built-in, motor feedback encoders.”
Overall, the market for stand-alone absolute systems will continue to grow due to greater encoder exposure in new industries.
The Engineer’s Top 3
What to consider when you spec an encoder.
How can I utilize the advantages of absolute encoder technology? Using an absolute encoder can significantly lower overall system costs. No additional reference point sensors are needed, positioning and motor-control can be done using one sensor, bus systems reduce wiring costs and multi-turn technology can replace expensive mechanical gearing and transmission solutions.
What resolution/accuracy does the application really demand? Encoders are often over spec’ed, which may lead to higher costs than necessary.
Which interface is suitable? For replacing a potentiometer, a simple analog interface may do, but for larger scale applications a Fieldbus (DeviceNet, CAN, etc.) may be more suitable and cost efficient. For many applications, a fast serial transmission is a good choice.