GPS-piloted tractors save farmers thousands of dollars with the operational efficiencies they create. Unaffected by fatigue and poor visibility, they reduce distances traveled by each vehicle, are accurate within inches, and save on fuel costs while improving crop yields.

They also create new challenges. For example: with no human around, how do you tell when a machine is approaching a breakdown so you can shut it down before significant damage occurs? The answer is Timken off-axis magnetic encoders.

They are highly resistant to the dirt, condensation and vibration found in agricultural applications. An optical encoder could succumb to these environmental issues. Magnetic encoders are unaffected and continue to operate through it all.

To discuss Timken off-axis magnetic encoders and other applications where they could be your solution, reach me at 603.355.4502 or send me at email at [email protected].

Photo Credit:  Shutterstock © Denton Rumsey

In industrial automation and motion control applications, selecting the proper encoder technology is key to maximizing performance. Optical or magnetic, which to choose?

Optical encoders perform well in clean environments, but what about those that are dirty, hot, humid or subject to high levels of vibration? Are magnetic encoders a better option in those cases? Let’s take a closer look at each.

Optical Encoder Technology

• Optical encoders pass a beam of light through a series of windows in a rotating disk. Any contamination that impedes the light source will cause encoder failure. This includes condensation from fluctuating humidity and temperature.
• Optical encoders require a precise, small air gap, often less than 0.25 mm (0.010 in.). As a result, they not only require very small shaft end play but they are vulnerable to shock and vibration.
• Because of their need for a clean, protected environment, they often are protected by an expensive, bulky package to help isolate them from the elements.

Magnetic Encoder Technology

• Magnetic sensing does not need a clean, transparent gap. Dirt, dust, oil, condensation and other non-ferrous contaminants do not affect their reliability.
• Magnetic encoders also are inherently shock- and vibration-resistant. The sensor-to-target gap is large compared to that of an optical encoder, and can be as large as 4 mm (0.157 in.). They can handle shaft end play as high as 2.5 mm (0.98 in.) total.
• Modular magnet encoders do not require an expensive, ruggedized package because the magnetic technology can handle dirty and harsh environments up to 135° C (275° F). Digital quadrature output signals are the same as in an optical encoder and their accuracy is sufficient for most applications where optical encoders are typically used.

The Most Attractive Choice

Magnetic encoders offer a number of clear advantages over optical encoders including:

• Greater durability
• Higher reliability
• Compact packaging
• Much larger gap tolerances
• Higher temperature range
• Harsh environment operation
• Higher vibration and shock tolerance

When selecting the proper encoder technology for an application, engineers should consider environmental, packaging, resolution and cost requirements. In cases where performance requirements can’t be compromised and the operating environment could be challenging, magnetic encoder technology can meet a customer’s needs at a relatively low cost.

Learn more:

Read our white paper, “The Advantages of Magnetic Encoder Technology in Harsh Operating Environments.”

Ask me about our success in harsh duty automotive, off highway and industrial applications.  Reach me at 603.358.4760 or send me an email at [email protected].