Where to source magnetic encoder and ring?

I would like to evaluate the magnetic encoder suggest by oskar => Project HoverArm

namely the AMS as5311 (AS5047P breakout board) => https://ams.com/AS5047P
and its 128 magnet ring.
=> http://ams.com/eng/Products/Magnetic-Position-Sensors/Magnets/AS5000-MR10-128

problem is

  1. for the breakout board
    digitey offers next dispatch in late july
    and mouser in late august

  2. and for the ring, i have no clue since neither digikey nor mouser even know the reference.
    While browsing on ams.com directly, the ring reference links is broken and the breakout board is greyed out (looks like they have nothing left in stock and must produce them again)

Where can i source them in a reasonnable delay (say 1 o 2 weeks)?
or an alternative sourcing for a different yet comparable product?
breakout board on aliexpress requires me to solder things which is likely to end up being a mess + they might be counterfeit anyway :’(

i’m lost :’(

Don’t order single AS5311 from Ali Express. I did, and it was fake (I tested 3). The only other option to order the encoder was the development board, again from Ali Express since they were out of stock everywhere else. This time I received working product. Also the marking on the chip was a little different, making me sure the first was fake.
I got the rings from AMS directly as free samples, but I can see that the link is broken now. Unfortunately it might be difficult to obtain the rings at the moment.
The rings are fragile. I broke one. So I treated the two last ones very carefully for installation.

I can’t seem to find this 128-pole magnet ring anywhere. The AMS 128-pole magnet ring page no longer exists, and it seems as though none of the typical stockists (e.g. RS, Digi-key, Mouser, Farnell) have it. There are a few other sites that seem to have it but they seem like niche magnetics suppliers that want you to request a quote for what should be a $30 item.

Any idea where to find one Oskar?

I have exactly the same problem => Where to source magnetic encoder and ring?

please let me know if you find a decent supplier (preferably in eu :p)

Hm sorry I got mine from AMS’ website. Maybe reach out to AMS directly and ask them what’s going on, if they plan on supporting this or if it’s just temporary problem in their supply chain? If they can recommend a supplier?

Some search results:

http://www.hs-magnets.com/Sensor-Ceramic-Magnetic-Multipole-Ring-1-0mm-pole-length-128-poles-mag891.html

https://www.ec21.com/product-details/CRD42.5-38.5-1.5mm-Sensor-Ring--10471110.html

https://www.sensitec.com/products-solutions/angle-and-length-measurement/pole-rings (model MWx0128FAB)

I will call them on Monday. Unfortunately it seems they don’t have any email address listed on their website, only an Austrian phone number. I’ll let you know how it goes.

Edit: Just filled out the enquiry form instead.

Hi cbrunschen,

I also found this company: http://www.spmagnet.com/m_article/41-128-poles-magnets.html

… through one of the links you posted. The model number is the same as that used by AMS. I’m not sure about the authenticity of the product, but Super Magnet claim to be the manufacturer. Perhaps Super Magnet are AMS’s supplier?

I will see if I can track down another reseller that sells low volume.

IIRC the supplier for the ring magnet to AMS was Bogen: http://www.bogen-electronic.com/en/magnetic-measurement-solutions/magnetic-scales/incremental.html

AMS replied back to me.

The supplier for the magnet ring was Bomatec, who apparently still stock it.

https://www.bomatec.com/en/

It looks like element 14 may be getting more stock towards the end of the month. http://www.newark.com/ams/as5000-mr10-128/magnetic-position-sensors/dp/18AC8311

image

That’s exciting news… I’ll definitely order some if that’s the case.

Hi,

I managed to source 20 magnet rings from SP-magnet for 100usd with shipping. They accepted paypal and I had the magnets on my desk within 3 days, so far relay good. But I have not been able to test them as I don’t have any encoder, I have placed an order at Mouser but now they moved delivery date to January… seems to be some problem with manufacturing if someone has more information please share.

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I’m also looking for rings and encoders now. May theres an alternative from rls.

I am also looking for a similar combo (encoder + ring) but could not find anything in stock.
Where are you currently getting yours?

Thank you for the good information.^^

Does anyone has any updates?

I found a few taobao sellers that carry encoder magnet rings. For example:
https://item.taobao.com/item.htm?id=39312517351
https://item.taobao.com/item.htm?id=556340734658
https://item.taobao.com/item.htm?id=562468321611

I am tempted to order a few via Bhiner (taobao shopping service) but I am not sure how to mount them. They seem to be of the sintered type which is quite fragile. They are also magnetized radially as opposed to axially and that limits the locations of the read head.

In contrast you can get thin axial magnet ring made with “vulcanised elastoferrite” on a steel hub for $60-100 (https://www.rls.si/eng/products/rotary-magnetic-encoders/incremental-encoders/axial-magnetic-rings).

Why a ring as opposed to the bipolar disc that comes with the evaluation module? e.g. as5047p-ts_ek_ab

Rings tend to be multipolar, so are no good as absolute encoders, only good for incremental so the motor needs to be calibrated on boot

Ring encoder is the only option when on-axis encoder cannot be mounted at the end of the rotating shaft due to space constraints. Double shaft hub motor is one such example. Ring encoder can also provide much higher precision. They are commonly used on main spindles on CNC lathes.

You are right they can’t provide single turn absolute position compared to on-axis encoder. But for multi-turn applications you would need to track the turn count anyway.

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