[time-nuts] Lucent KS-24361 GPSDO arrived today several questions
GandalfG8 at aol.com
GandalfG8 at aol.com
Thu Nov 6 12:52:51 UTC 2014
Hi Bob
I view the master/slave situation the same way you do, but only commented
because Lucent effectively sets things up the other way round so just
wanted to be sure which way Paul was considering it.
As regards, the "faking", yes, a single 15 way plug containing just a link
and a resistor is exactly what I use now.
I realise the RS422 fudge isn't ideal but certainly very handy for some
quick tests.
I've got two or three RS422 PCI interfaces but hadn't previously had any
spare slots, now I've got a couple of lovely Magma 13 way PCI expansion units
but need to hack them about so the ports are at the front.
Whoever decided rack mount PC kit should be built with all the connections
at the rear must have been really nuts, and it was too long ago to use
"corridors" of racks as a viable excuse, someone somewhere just fitted ears to
desk top style cases and left the rest of us to get on with it..
One of the best things I ever did was to buy a pair of "back to front"
rackmount PC cases with all ports and cards available at the front, trouble is
now I want everything else to match, and most test gear has just the same
issues!
All good fun, and certainly never a dull moment:-)
Regards
Nigel
GM8PZR
In a message dated 06/11/2014 12:04:47 GMT Standard Time, kb8tq at n1k.org
writes:
Hi
> On Nov 6, 2014, at 3:44 AM, GandalfG8--- via time-nuts
<time-nuts at febo.com> wrote:
>
> Hi Paul
>
> Prime question is what are you calling the "slave" unit?
1) Slave in the sense that it’s slaved to the GPS in the other box. Unless
we find a serial link from the Ref-0 back into the Ref-1, that’s all it’s
doing.
2) It fires up and the Ref-1 box gets all organized and locked up. It goes
“ok” first, then the Ref-0 goes “ok” (locks to GPS). In that sense, the
Ref-1 is the master.
My guess is that they default to output from the Ref-0 rather than Ref-1
because it’s the one more likely to fail (more single points to go wrong).
> 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
Yes it is confusing - sorry about that
> 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.
So a single 15 pin connector with one jumper and one resistor (or jumper)
plugged into the interface socket.
>
> 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.
Works, but if you have an old style +/- 12 V RS-232 signal, things might
or might not work forever. A lot depends on how they have protected the
chips. They expect a 1.5 to 3.5V signal on the input, so even +/-5 is a bit
exciting. Full blown RS-422 interfaces are sub $15 gizmos.
Bob
>
> Regards
>
> Nigel
> GM8PZR
>
>
>
> In a message dated 06/11/2014 01:24:33 GMT Standard Time,
> paulswedb at 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
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