Steve Blackmore wrote: > Hi Jon - encoders here are only 90 and 120 ppr respectively as they are > connected via parallel port as I had problems with higher value encoders > being read reliably at anything more than a thousand revs or so. > > It almost seems that every time it gets an encoder pulse it gives the Z > axis a kick. The faster you go the less noticeable it is, but at slow > speeds it's poor and sounds like what Gene described. > OK, my Bridgeport encoder would be called an 81 PPR encoder, as there are 81 teeth on the gear. And, it works fine. I am using a hardware encoder counter with it, but if the signals are properly being read by the parallel port, it SHOULD work well. So, there is something wrong there, but I can't tell what at this distance.
Yes, software counting has severe limits on the count rate. Well, 120 PPR is 480 counts/rev in quadrature counting all transitions, and 1000 RPM is 16.67 revs/sec. So, that is 8000 counts/second. Depending on the BASE_PERIOD, this could already be a problem. Jon ------------------------------------------------------------------------------ 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
