[time-nuts] Lucent KS-24361 GPSDO arrived today several questions
kb8tq at n1k.org
Fri Nov 7 18:04:10 EST 2014
Ok, If you have a solid ground and a good scope:
The data should go between 1.5 and 3.5V on each of the two outputs. The transitions are nice and fast. No noise, nice clean square waves.
The input lines on the interface idle at 2.5V.
The idle voltages on the pins can be checked with a simple DVM, no scope involved. Check them before you attach anything to the port. One output pin should be at 3.5 the other at 1.5V. Both inputs should be at 2.5V.
Once you connect up your RS-422 converter, the outputs should still be close to 1.5 and 3.5V on the DVM. The inputs should also go to at least 3V and 2V. Ideally they would go to 3.5 and 1.5V. Exactly where they go depends on your RS-422 converter.
What voltages do you see on the J-8 Diag port pins with nothing connected to them?
What voltages do you see on the pins with the USB to RS-422 converter attached to the J-8 Diag port?
If things get weird when you connect the USB to 422 converter, check the voltages on it’s pins when nothing is connected to them. They should follow the same pattern as the J-8 pins.
Most likely gotcha’s:
1) RX is connected to RX and TX is connected to TX (should be RX to TX and TX to RX).
2) The USB to RS-422 is putting out something odd (like 1.3V centered levels).
3) The software up the line from the interface is not really working right
To check the software:
Connect the RS-422 converter in loopback (RX out wired back to TX in). Bring up a terminal program, type in anything, see if it echoes back.
> On Nov 7, 2014, at 11:34 AM, Anthony Roby <aroby at antamy.com> wrote:
> My frustration with getting anything out of the Diag port onto a PC continues. I received an RS422 to USB cable and also an RS422 to RS232 convertor but neither of them has given me any success, on either box. I can see data coming out of the port on my scope, on top of a noisy 1.2V line, but cannot get a terminal program, SatStat or Z38XX to display anything. It's crazy.
> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Bob Camp
> Sent: Friday, November 07, 2014 6:42 AM
> To: GandalfG8 at aol.com; Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Lucent KS-24361 GPSDO arrived today several questions
> Well, it took me a *long* time to get around to the command line on these boxes. For what ever reason (yes one could guess ? ) I stayed focused on finding a 3810/11/12 manual rather than dropping back to the 3801 manual.
> Now the question becomes that magic 10 pin header on the board. If it ??s jumpers (might not be) one of them could enable bi-directional communication.
> Thanks for checking this to see that it works on at least one other box.
>> On Nov 7, 2014, at 4:03 AM, GandalfG8--- via time-nuts <time-nuts at febo.com> wrote:
>> Hi Bob
>> Very many thanks for the prod re the Diagnostic port.
>> Considering the other GPS kit I talk to using Hyperterminal and the
>> like, often because there's no other option, I don't know why it's
>> never occurred to me to do the same with the Z3801As and now these......
>> and any rude suggestions as to why will just be politely ignored:-)
>> It's not that I don't have access to the command set, but I suspect
>> that twelve years or so ago, totally green when it came to GPSDOs and
>> with my first Z3801A to play with, I was just grateful to find
>> SatStat, and eventually some nice commercial options, and never gave
>> it a thought after that, silly me.
>> Anyway, I've just switched my Z3811A comms over to Hyperterminal and
>> tried the :SYST:STAT? command for starters.
>> That's obviously what SatStat uses to generate it's front page,
>> although it is continuously updated with SatStat, and we do have
>> contact, and something else to play with:-)
>> In a message dated 07/11/2014 00:07:56 GMT Standard Time,
>> kb8tq at n1k.org
>> Ok, I got to spend a little quality time with my pair today. I mostly
>> poked at the Diag port with a terminal program.
>> Both of the units seem talk over the Diag port regardless of the mode
>> they are in (master / slave / fault ). Both respond to a sub-set of
>> the Z3801 SCPI commands (= not all commands work). There are a few
>> enhancements where a query to a ??node ?? gives a reply (which it should not if it ??s ??node only ??
>> ). All of it works ok at 9600 baud 8N1. All of it comes back with an
>> error message (E-xxx) after a valid command response. It may not like
>> the terminal program sending cr/lf or something like that.
>> By far the most useful thing to type is :SYST:STAT?
>> That executes the system:status request and gives you a nice full
>> screen of information. It shows you about 95% of the useful
>> information all on one page. About the only major thing missing is
>> the DAC value. That ??s available with another command out of the
>> Z3801 list. It does take a while to compose and transmit the screen,
>> so it ??s not the best way to to this forever and ever.
>> The data from the request is the same on both boxes. Same everything
>> except one shows as standby etc. The interesting details are things
>> like elevation mask and cable delay. Why interesting? You can set them
>> with discrete commands. You can also query the data with the same
>> commands to make sure the box ??took ?? what you sent.
>> This allows experimentation with changing the elevation mask on each
>> box (or just simply doing a discrete query for the mask on each box).
>> The Ref-0 / slave will happily change things around with discrete
>> commands. None of them are reflected in the :SYST:STAT? listing on
>> the Ref-0 or Ref-1. When you look at the Ref-1 / gps box, it ??s
>> discrete query information matches the :SYST:STAT? screen on both
>> boxes. When you change things on the Ref-1 box both screens follow that data.
>> ?? ?? ?? ?? ??
>> When you pull the antenna on the gps box, it immediately (almost)
>> goes into gps fault led flashing mode. The slave box happily sits
>> there for a while (say a minute) with it ??s gps led saying all is
>> well. When you plug the antenna back in, the process is reversed. The
>> gps box goes out of flash mode right away. The led goes out in a bit.
>> The led on the slave box does not follow for a minute or so.
>> ?? ?? ?? ?? ??
>> All of this suggests to me that the Ref-0 / slave does not talk back
>> to the other box via serial. It also suggests to me that all it
>> ??sees ?? from the Ref-1/gps box are the duplicates of the serial
>> string out of the Motorola gps module. The Ref-0 just figures out
>> what ??s happening by watching those strings as they roll by.
>> Hope that makes sense ? .
>> ?? ?? ?? ?? ?? ??
>> If that ??s all true, it should be ??easy ?? to put dummy gps
>> sentences into the Ref-0 interface port and a pps from something
>> else. Once it sees stuff that it likes, it will start locking up to
>> that pps. Cheap micro and just about any modern gps = fancy new
>> GPSDO. Quick / easy / not much work. A little more complex if you
>> decide to translate sawtooth data. That of course assumes these boxes do anything with sawtooth ...
>>> On Nov 6, 2014, at 7:52 AM, GandalfG8--- via time-nuts
>> <time-nuts at febo.com> wrote:
>>> Hi Bob
>>> I view the master/slave situation the same way you do, but only
>>> 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
>>> 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
>>> spare slots, now I've got a couple of lovely Magma 13 way PCI
>>> 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
>>> 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
>> 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
>>> All good fun, and certainly never a dull moment:-)
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