Hi > On Nov 6, 2014, at 3:44 AM, GandalfG8--- via time-nuts <time-nuts@febo.com> > wrote: > > Hi Paul > > Prime question is what are you calling the "slave" unit? > In normal use Lucent treats the Ref-0 unit as the master and Ref-1 as the > slave, but it's Ref-1 that contains the GPS module. Bit confusing but if > you've got Ref-1 with the GPS module then you're in business:-) > > It's turned out the transistor delay circuit isn't needed after all and the > wiring can be simplified too. > > All that's necessary to run the Ref-1 stand alone is to ground pins 2 and 3 > on the J5 interface connector and there's a couple of convenient ground > pins already on that connector, 8 and 13. > In normal use pin3 is tied hard to ground, presumably via direct link from > the other module, so that can just be a wire link to either pin 8 or 13. > Pin 2 is normally held at a logic low level so although a direct ground > seems to work ok for that too, and no damage noted so far, I prefer to play > it safe and ground that one to the other ground pin via a 470ohm resistor, > which also works fine. > That's it. > > The LEDS should flash at start up, followed by "No GPS" and "Fault" on > solid whilst the unit goes through acquisition and lock, this can take an > hour > or so, and then those LEDs should go off and the "On" light should be > solid. > At this point the 15MHz and 1PPS outputs are enabled. > > The J8 diagnostics connector is enabled from start up and SatStat can be > used to monitor progress. > The RS422 3 wire fudge suggested by Stu Cobb works fine for me, J8 pin 7 to > PC 9 way comm port pin 5, J8 pin 8 to comm port pin 3, J8 pin 9 to comm > port pin 2.
The interface chips are DS75176’s. They will accept a +/- 7V “ground offset” or a -7 to +12 signal and run forever. Absolute max on the inputs is rated as +12 to -10 V. A +/- 5V output RS-232 will work ok. A +/-10 or greater might be a bit much. A fairly common voltage doubler RS-232 chip running on +5.2 would be questionable. Add in a ground offset and things could get a bit more exciting. The expected logic swing is 2.5 +/- 1.5. That should work fine with a +/- 5V RS-232. If you have a real oddball that puts out +/- 3 V (get a new one …) it could be a problem I suspect that if you have a +/-3V RS-232 port you already know that there’s a lot of stuff out there that does not work with it. There’s not much margin in this case. Add noise or a ground offset and things get messy. Bob > > Regards > > Nigel > GM8PZR > > > > In a message dated 06/11/2014 01:24:33 GMT Standard Time, > paulsw...@gmail.com writes: > > I have been following the threads on the KS-24361 some of the longest I > have ever seen on time nuts. > So I have a very basic question. > There was a 2 transistor delay circuit by Arthur way back. I believe this > is needed. > But then the pin numbers seem to get a bit mixed up and there are some > jumpers with several comments. > Is there a clear guidance on what to do? I do not have the slave unit. > Power is not an issue. > Thanks in advance for your help. > Must say the units very nice. > > Regards > Paul > WB8TSL > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
