Stuart Stevenson wrote: > Gentlemen, > I tried a different cable. A 3 ft cable. I saw the same results. > The table moves .200 per motor revolution. I took the side plate > off the drive mount and counted the revolutions per inch. I moved the > table 1.0 inches with a g91g01x1.0f100.0 command. I saw exactly 5 > index pulses per 1 inch move in both positive and negative moves. I > expected to see five unless the start of my motion was exactly on the > index pulse and then I would have seen 6 pulses in a 1 inch move. A > not very likely event. > Jon Elson's approximate .020 grid estimate seems to me to be very > close to what I see. I haven't tried homing in the positive direction. > I will do so tomorrow morning. I will let you know what happens. > Is there anything else anyone would like to see from me? Well, what I was seeing with halscope showing the 3 pins ppmc.0.encoder.00.position, ppmc.0.encoder.00.index-enable and ppmc.0.encoder.00.index
When it was misbehaving, I saw it recognize an index pulse, and then make the move to the offset index position. If it saw an phony index pulse early, due to noise, then I'd see the REAL index pulse show up during the move to the offset index position. > I hope I get emails tomorrow. We are having our ISP change our > email host this evening. Regardless, I will test the positive > direction and report it. Well, I don't think that's the problem. Did you set the encoder board's jumpers for differential? (I assume you are using a differential encoder.) I'm quite convinced this is noise on the encoder's index pulse. The way I set this up, there is no filtering on the index pulse input, so even a 10 ns wide pulse of noise will trip the index logic. One way to check this might be to put a 100 pF capacitor on both of the differential index signals to ground. If that even changes the frequency of the symptoms, it is pretty clear proof it is a noise problem. Jon ------------------------------------------------------------------------- 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
