AS5311 encoder 2 µ for VERY little money
Have you ever of AS5311 from Austriamicrosystems ?
It's an encoder incremental in quadrature (A B Ix) AND absolute with Index incremental step 1.995µ 2mm/1024
Since I drive my mill directly with my linear encoder 5µ(200 steps mm) its definitely possible to drive it with 500 steps/mm
I presume that the division of the step is programmable (like the CUI encoder)
http://www.austriamicrosystems.com/c...heet_v1_05.pdf
It use Magnetic multi-pole strip, 1.0mm pole length, w=10mm, h=1.3 mm ,strontium ferrite bonded, length up to 50 meters!!!, precision 40 µ 20 µ or 10 µ per meter !!!
It cost approximately 6$ (for 1000) but the price per unit on the net is about 10$
I am waiting for the cost of the magnet with 10µ accuracy per meter but austriamicrosystems sale a piece of 30cm for 6$ so 20$ per meter
http://www.austriamicrosystems.com/c...6/644528/62494
a small test board is sold but for 70$ i prefer use my mill to make the board !
I will order it as soon as i get info for the price of the stripe and tell you about!
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After reading carefully it does not seems that we can program the resolution so the parameter that should be given in number of step per mm in linuxcnc(emc2) should be 512 !
"http://www.youtube.com/watch?v=gK14SaaYMoc"]CNC laser galvo scanner head test - YouTube
A video with the AS5311 used to give the angle position . The device is clearly use off limit (in this case the magnet should be an arc !!! ) but the result is still pretty good.
This show the ease of use of such encoder !
Last edited by rokag3; 03-22-2012 at 08:23 AM.
Interesting chip.
Available at Digikey for $10.38CAD
Now where to get magnets...
they sale also at digikey but only linear of 30 cmOriginally Posted by vegipete
by the way i get the price per meter in 40µ/meter equivalent C5 it's about 40euros/metre and with 10µ/meter equivalent C0/C1 it's 70 euros/meter at bogen
Buy Magnets Online / Magnets / Magnetic Encoders / Products / Home - austriamicrosystems AG
here is bogen link Bogen Electronic - Home
you may find other supplier maybe
the 10µ/meter cannot be rolled they have adhesive and if you want to use it on harsh environment you can have the magnets with a protection!
I wait for my samples !!!
Last edited by rokag3; 03-23-2012 at 10:56 PM.
I am so dumb !!!
I contact Austriamicrosystem and they offer me a sample of the AS5311
guess what ?
I give a wrong postal code!!!
In fact i use paypal and i was not too sure about my postal code. Since i receive all my mail no the PC i just forgot it
I am making a test board to be machinate and i will post the Gcode !
Do you have a Digikey part number?
Digi-Key - AS5311-ASST-ND (Manufacturer - AS5311-ASST )
I found the chip, but not the magnetic strip. Is there a part number for the 30cm magnetic strip?
I receive my sample , since i have not yet the magnet i am going to test the as5311 as a rotary encoder
This chip is so small !!! in fact when you get it you think it' a mistake and there is nothing in the package !!!
We make a test with our mill to make the "printed circuit" we have made a tool with a carbide broken mill after finding the correct height we manage to get a cut of 0.25 mm pretty clean (in fact we use the "cutter" strategy
I am redesigning the board to make it more easy to carve
Thanks.
I also found makerbot sells the low resolution variety, 15um at $3/foot - Magentic Adhesive Strip - MakerBot Industries
They also sell a complete kit, using the AS5306 - MakerBot Magnetic Linear Encoder v1.2 Kit - MakerBot Industries
This will interest a lot of guy in robotic but 15µ is far too much to drive a servo. 5µ is already a bit lousy . the mistake of gecko is 256 steps if you have 5µ step this make 1.28mm with 15µ it make 3.84 mm with 2µ make 0.512 mm
but continue to look this at least is a good catch !
if he work off axis it's also interesting for a magnet ring encoder for the spindle since 2µ mean a very small ring or very low speed
Last edited by rokag3; 03-28-2012 at 11:05 PM. Reason: remark on the spindle encoder
Ok I have done the circuit I will engrave it with our mill and just a carbure cutter, our test was positive let's see the real thing
We are going to make a special tool it's easy to cut a line of 0.5 mm and keep a copper line of 0.5 mm
to make it 2 time smalle implied a rotative needle cut un half to the tips (we have a diamond tools to dress our own tools it will help) this tool should ideally rotate at 30000 rpm
the maximum we can make is 4200 rpm so we are going to cut at 20% of the speed
The AS5311 has a maximum speed of ~650mm/s which may not be enough for some machines (Pick and place ?) - Therefore I'd suggest the AS5306.
The AS5306 has a maximum speed of 12m/s (Unfortunatly there isn't an in-between model) and an accuracy of 15um but also has some nice features such as limit-switch-less homing. (By allowing it to go off the track and using the index pulse.)
Here are some boards I designed for them, along with the Eagle part library:
http://yngndrw.hostilezone.net/uploa...%20yngndrw.zip
Please note that these have not been tested / produced. There are also the Gerbers included using the Fusion PCB Service CAM files:
Fusion PCB Service [PCB08511P] - $9.90 : Seeed Studio Bazaar, Boost ideas, extend the reach
Thank you very very much for your links.
650mm/s may not be enough for positioning machines but always enough for huge majority of machines tools 39m/min the few that goes faster work very often in clean places and optical encoder make the job.
Also you rarely if never need 488 nanometre on a >39meters/minute
But to drive a servo, 2µ step is ok and a DRO of 488 nano is a good indication to check your wear and how it evolute.
the as5311 as an index every 2mm or if you use it with a single magnet positioned on the end of the axe in rotary 1 every 360°
it's pretty easy to make a small circuit that will stand by with a battery and memorize the index counter (16 bits 131 meters!!! )
We have mill a prototype of our AS5311 circuit I test various width they all york fine but the 0.27 is the fastest to mill the others need many passage also it will be better to put some ground between the piste and it is very impressive to see a so big machine so accurate !
At least i will make all my electronic prototype with that !cheaper cn't be made (specially since we grind the tool ourself)
2*10 pins 0.27mm space and 0.36 mm coper
the tools is a home made 10 mm carbide vith an angle of 10 degres with one tooth
the pictures are taken with the microscope X30
I train my skill in soldering on this i use fr that old memories of pc , unfortunately the pins of the memory chips are larger than the AS5311 but after welding the height circuits i will have a good skill
I remind you that our table is driven in X Y with our linear encoder
the 4th picture is taken in transparency
in fact out tool should be 9 degrees not 10 but i prefer have a bigger space in between the line in fact i weld it pretty easily !
after milling i have put some varnish and i put grease on the part to be welded.
You can see the eccentricity of the tool on the small dents that appear on the edge of the piste the tools rotate at 3500rpm and the advance was 500mm/min it take 4 minutes to make it
definitely a higher speed of rotation will be better but this machine is not buils to make so small milling
The linear magnets are much too expensive for mée now, i am going to conduct my test with rotary encoder.
Also since we have a very reliable control of speed and distance i plan to make a recording head and put it in our mill with a reverse polarity every mm!
should I use a mask in mumeta ?l
I am goinfg to conduct some test with fridge magnets,
Since the magnets provider are so non cooperative i will try to make an alternative technique to record this type of magnets and put it in public domain !
If someone get some info it's welcome
It' not the first time that we make supposed to be impossible things !
I find a link Refrigerator Magnet Encoder
Last edited by rokag3; 04-03-2012 at 10:40 AM.
this is with the as5311 in position it fit perfectly !
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