I've tried a few variations on EOI/EOS behavior. It's definitely not sending either EOS characters or asserting EOI in the cases where the timeout occurs... it's just not sending anything at all in those cases. ibcntl=0, indicating no traffic arrived at all.
It seems that the DTS just doesn't like asynchronous queries. I eventually ran across an app note that indicates the need to serial-poll the instrument, waiting for a message-available flag before addressing it to talk. That will most likely take care of the issue, I'm hoping... -- john, KE5FX > -----Original Message----- > From: [email protected] [mailto:[email protected]]on > Behalf Of Ulrich Bangert > Sent: Tuesday, November 23, 2010 9:49 AM > To: 'Discussion of precise time and frequency measurement' > Subject: Re: [time-nuts] Wavecrest DTS 2070 GPIB access > > > John, > > I do not have any experience with the Wavecrest but my experience with > devices that do not seem to answer on bus requests is that they often DO > ANSWER the request but after the answer they do not serve the > bus's EOI line > correct. Checking the EOI line is the standard way that the controller > checks the presence of an answer with. For me this was the case at least > with a HP3457 multimeter as well as a R&S URV 5 rf power meter. > > If you use a NI compatible plugin card with the accompanying DLL > you should > make yourself a debugging aid that enables you to display the contents of > the input buffer (the one you give the pointer to the dll for a read call) > in case of timeout. For me usually the correct answer was to be found in > the input buffer despite the timeout. That was the reason why I > switched my > EZGPIB communication completely from EOI to EOS. Even the instruments that > do not serve the EOI line correct seem to send a correct string > termination > as <CR> or <LF>. > > 73s de Ulrich, DF6JB > > > -----Ursprungliche Nachricht----- > > Von: [email protected] > > [mailto:[email protected]] Im Auftrag von John Miles > > Gesendet: Dienstag, 23. November 2010 11:27 > > An: [email protected] > > Betreff: [time-nuts] Wavecrest DTS 2070 GPIB access > > > > > > I'm looking at writing some code to drive the DTS 2070, but > > have been running into timeout errors performing any GPIB > > query (even *IDN?) while the instrument is taking > > measurements, even in sizes/sets of 1/1 at a 1-pps rate. Has > > anyone else run into this before? > > > > This happens equally with either a Prologix GPIB-USB adapter, > > or an NI PCI-GPIB board, both of which are otherwise reliable. > > > > -- john, KE5FX > > > > > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
