|Another option I have considered, is to use Hall sensors which would |work okay without an enclosure, but I seem to recall that Hall sensors |are not very fast, though engine crankshaft sensors seem to work well |enough.
Here is a new encoder option on the market that looks very attractive, the: AS5040 10Bit 360° Programmable Magnetic Rotary Encoder These are chips with hall sensing of a single magnet positioned over the chip. this one gives 10 bit resolution and in the quadrature mode has this to say about speed: The incremental outputs are not affected by rotational speed restrictions due to the implemented interpolator. The incremental output signals may be used for high-speed applications with rotational speeds of up to 30,000 rpm without missing pulses. There is a delay from the actual position change to the time it is reported, but it looks like it could follow a 1500 RPM motor without interpolating, and if used with a spindle at constant speed, since you're looking for the index pulse to line up at the same spot every time for threading, it might work for that application too, as long as you didn't have to sync up the thread start with some feature cut at low speeds. Some of the chips in this series are available from component distributors for around $10 each in onesies, and I remember seeing the magnet specific to this application for sale also. There is a company that has put out an encoder using the AS5040 at this link: http://nubotics.com/products/me110/index.html ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
