Quote Originally Posted by Chaz View Post
https://www.ebay.co.uk/itm/Hengstler...EAAOSwySlaJSLx
I was looking at that earlier - the listing isn't very helpful as it only quotes the P/N and not the code that gives the spec - zooming in on the photo it looks like it's a D/500 which from the datasheets I've seen give it a 500 counts per rev, which is well under the minimum spec. for the Acorn.

I checked the resolution a 2000 count encoder would give assuming a workpiece of 250mm diameter, and it's about 0.4mm, so having 2000 as a minimum spec. doesn't seem that unreasonable.