Jon Elson wrote: > One possibility that might be causing the problem is digital > filtering of the encoder signals. If the width of the index > pulse is VERY short, like a couple us, it may be missed by the > hardware that resets the encoder count on index, but will always > be seen by the D FF that senses the rising edge of index.
This is EXACTLY the kind of thing that would explain the results that Stuart is seeing. You may recall I suggested that he try using halscope to monitor the encoder feedback and trigger on the falling edge of index-enable. When index-enable falls, the position feedback should be zero - easy to see with halscope. If either one of you can make the problem occur reliably, please do that test. Its 4am here, and I'm going to bed, but if you need step-by-step instructions, just ask and I'll post them tomorrow. If the hardware/driver combination clears index-enable without resetting counts and position, that is definitely a bug in either the hardware or the driver. I'm very surprised that you have two separate hardware paths, one for resetting the counter and a different one for reporting the index pulse to the software. That is a race condition just waiting to happen. > But, I don't think this scenario would be triggered by whether > the home switch was tripped or not when you initiated the home > sequence. So, I think maybe something else is happening, > causing the homing state machine to work in a different manner. Your message says it misbehaved once when you started homing while on the switch, and never during several tries when you you started from off the switch. You don't say if: A) you tried it on the switch several times, and it repeatedly failed, or B) you only tried it on the switch once. If B, it could be a random failure that just happened to occur that one time when you were on the switch - no cause and effect relationship between the failure and where you start. If A, then there is probably some connection... maybe the axis is running at a different speed in the two cases. In any case, if its A, then the problem is repeatable and you can halscope it. Regards, John Kasunich ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
