Absolute Rotary Encoders

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I'm looking for absolute rotary encoders with at least 18 bit
resolution for a product currently in design, does anyone have
any brands or products they can recommend / not recommend?.

TIA
Mark


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Are you sure? What on earth do you need *that* resolution for?

petrus bitbyter



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Yes I'm sure, it's for an optical grinding application

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Erwin Sick Australia have the Stegmann range. The AFS60 range are 18 bit
absolute single turn resolution. They have up to 30 bit multiturn.

Have used them in the past, and they have an easy to use RS422/485 or
SSI output.

David

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Spoke to a Sick Stegman rep the other day, He said the AFS60 was so new
they didn't even have an Australian price for it let alone a unit in the
country and then emailed me a price.

The price goes up every time I phone or email them. Maybe there is a
wide price variation between variants in the family.

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Sorry, I actually meant I had used the Stegmann range before (not
specifically the AFS60), but they all seem to have similar interface,
and ease if use.  I have no idea on pricing, as I normally only do the
engineering / interface to them, and am not involved in the purchasing.
Some of there stuff does look expensive (but nice !!)

David

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  Thanks David, while I've got you here, do you have any experience with
Hengstler or IVO encoders?, they have some nice units that may do the
trick in their online catalogues but I've never personally used them
before or even know if they are available/affordable.

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Hi Mark,

No, I have have not used the Hengstler or IVO encoders. We seem to
mainly get stuff from Sick, and I have to make sure that it works with
our equipment correctly

David

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"Mark Harrarse Craphead "
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** ???????????

18 bit resolution is one part in 262,144   !!!!!!!

Wot an idiot.



....  Phil






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Why would that be Phil? Thats a resolution of a bit over .001 degrees,
there are plenty of apps needing that resolution. Such encoders do tend
to be big and expensive though.

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You really do need to expand beyond toasters Phil. Plenty of encoders
out there have 18 bit single turn resolution. Here is a link for you.

http://www.stegmann.com/pdf/AFS60_AFM60_Brochure.pdf


Who's the idiot now, Phil?

David


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This encoder can be used to accurately check the vertical position of a
slice of bread in a pop-up toaster.
This method of toasting is excellent. As the bread dries out it shrinks,
with the aid of servo motors the slice of bread/toast can then be adjusted
to the correct position to obtain the best possible toast.
Phil is therefore quite correct - 18 bit resolution is a bit of an overkill
for this application, probably a 16-17 bit would suffice.
Having said that, maybe Phil is busy designing a new range of toasters and
wants to keep it hush-hush. I'm sure he is going to surprise us with a
super-dooper model using 5 servos and two 22 bit absolute rotary encoders
with a latitudinal and vertical take-off with differential correction
adjustable via a slot in the second element, unless he deploys three or more
elements to control the browning more evenly.
I await his new offering with great excitement.
Rumour also has it that his new toaster will be compatible with Facebook and
Twitter plus a whole host of other goodies.
It is possible though, that his first versions will only be available for
use with Windows. The Linux models will probably follow when the Kernal gets
transferred to Timbucktoo.



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Yeah, but will it brown evenly on both sides?

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Nah, That would require a 24 bit optical brownness sensor. Then we would
have even, consistent toast, and the setting dial would need to have
16,777,216 settings. Would avoid burnt toast however.


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I'd even go so far as to have a modified laser printer/toaster to print
images on the toast with a 60W laser.

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I would think that 60W would not be sufficient power to ensure fully
cooked toast. Perhaps Phil could enlighten us on the engineering behind
toasters.



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I suspect Phil would pulse the laser to create more power.
This way he would be able to get a BIT of toast without the use of BROWNout
protection.
He might employ two laser printers, one for each side, unless he is thinking
of a ROTARY turntable fitted with absolute encoding to turn the toast
around.
nobody is certain on his POSITION in this matter.



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Kneeling perhaps?



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Subserviant or bottom would be normal

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Optical encoders at that resolution will fail after a period of time as
the graticule's are too fine, even given small mechanical disturbances.

Geared encoders at that resolution will not perform due to mechanical
backlash.

you need dual speed synchro resolvers and a resolver to digital converter.

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