Absolute Rotary Encoders

"Mark Harriss" schreef in bericht news: snipped-for-privacy@westnet.com.au...

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

petrus bitbyter

"Mark Harrarse Craphead "

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

Wot an idiot.

.... Phil

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

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.

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

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.

Who's the idiot now, Phil?

David

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.

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.

Yeah, but will it brown evenly on both sides?

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

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

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.

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

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

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.

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.

Kneeling perhaps?

Subserviant or bottom would be normal

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.