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Where are the inexpensive magnetic linear encoders?

In an article in Control Engineering, Steve Feketa of Rockwell claims that magnetic linear encoders are available for $200 for a 1 meter encoder, while optical linear encoders can cost up to $2000 for a 1 meter encoder.

If you’re paying $2000 for an optical linear encoder, you’re either getting a very high resolution encoder, a very rugged encoder, or some golf at the country club for the encoder manufacturer’s sales team.  I can buy a nice optical linear encoder with a 1 meter scale for substantially less than $1000.

But I can’t find any information on inexpensive magnetic (or magnetorestrictive) linear encoders.  I do know of inexpensive optical linear encoders from US Digital and Avago that are under $200 for 34″, but they are hard to mount and the resolution is only 12.7µm.  I found that Heidenhain, Renishaw, Netzer, and Temposonics (magnetorestrictive) all make magnetic linear encoders.   I couldn’t find any pricing, and I’m not going to spend a lot of time trying to get quotations when I’m not ready to buy one.  I suspect that Netzer is the only one that might be close to $200 for a 1 meter length.  OK, New Scale Technology’s Tracker is probably under $200, but its length is only 8mm.

Why am I interested in low cost linear encoders?  Because the current cost of linear restricts their use to when I really need them (I’ve used linear encoders twice in > 10 years of machine building).  Even a low resolution linear encoder is helpful to minimize problems from backlash, and to provide feedback for linear motors.

For the hobbyist, eBay is one solution.  I recently bought two MicroE M2000 linear encoder read heads + electronics on eBay for a very reasonable price.  True, I don’t have the scales, but I’m not sure where I’ll use them, so that’s OK.

1 comment

1 Henry Menke { 08.08.11 at 11:56 am }

Hello Tony, I am a Product Manager at Balluff, Inc. We have some cost-effective magnetic incremental linear encoders in the BML product family, and some economical absolute magnetostrictive linear position transducers in the BTL family (the Micropulse AT). Let me know if we can help you out. – Henry

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