I solved my multiple-encoder problem for my linear motor. It turned out to be almost trivial. The encoder counter doesn't care where it is getting A and B signals from, just so each pulse represents a fixed amount of movement of the carriage. So I connect all my A&B outputs together with tri-state buffers and enable each pair in succession as the "valid" signal of a new encoder becomes active. I can now make my motor indefinitely long, with as many encoder modules as I want, at essentially arbitrary spacing (no calibration needed), and no special hal modules. Hal just thinks it is an ordinary brushless motor setup with a single encoder. My logic (as currently implemented) consists of two TTL logic chips per encoder head.
It is possible to have a tiny glitch at the transitions, but since these AS5311 encoder sensors have 2um resolution per count, I'm not very worried about a couple of counts every 75mm. -- Ralph ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
