Peter C. Wallace wrote: > SNIP... >> I found a more disturbing problem - both versions seem to lose counts >> going in one direction (but not the other). I have a 2500 line encoder >> hooked up, so I should get 10000 counts per rev. Going forward thats >> exactly what I get. But turning it backwards, I get between 9700 and >> 9800 counts per rev. I have a 7i31 LED board connected, so I can >> carefully turn the encoder until I see the index LED light up, and I >> know I've done EXACTLY one turn. >> >> I suppose I should try other encoder channels, and/or another board, >> since I have two 5i20s, but its late - I'll look into it more tomorrow. >> >> I'm using the bitfile that is compiled into the driver. I don't think >> the corresponding VHDL source is in CVS anymore, the source we have >> matches some newer bitfiles. I'll try one of the newer ones tomorrow. >> Testing a bitfile when I can't examine the source is futile. The >> source that I did examine doesn't have any obvious issues. >> >> Regards, >> >> John Kasunich > > > > Counting correctly in one direction and not the other could be an electrical > problem, but is most likely caused by a funky encoder (Needing A-B phase > adjustment)
Yes, I considered that possibility. It was late and I didn't feel like pulling out the scope to look at the waveforms. I'll do that next. Roger also suggested swapping leads, and I'll try that too. I certainly hope this is something I can blame on my encoder rather than the board. Regards, John Kasunich ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
