Hello, all, Last week I was having an anomaly where something would "trip" and cause a burst of following errors, real time overflows and loss of coordinate alignment. I was thinking it was an occasional IEEE-1284 timeout, but I was seeing a consistant side effect, that after this trip I couldn't raise the quill more than a quarter inch. Well, the Z home position is about 1/4 inch below the upper limit of travel, so it seemed that the Z encoder counter was getting zeroed. A reset signal on the IEEE-1284 does clear the encoder counters, among other things. I have had problems with this happening on other units, so I checked the actual voltage on the reset-not signal, and it was 3.7 V, even with the 100 Ohm pullup to +5 V on the PPMC motherboard. Hmm, that is a bit close to the threshold. So, I upped the filter cap on that line from 1000 pF to 10000 pF. I have run the machine for one evening and most of today, both from cold starts, and have had no more of these events. That is not a complete validation that this is the problem, but it looks like it may have solved it.
On the other hand, pumping 13 mA into the parallel port might not be such a great thing, although it ought to be 5 V tolerant. I probably need to put a small series resistor in there. Well, every time you think something is just totally working, another funny thing happens. I hope that is the last "funny thing". Jon ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
