[time-nuts] PRS10 not locking to 1PPS

Thu Jan 7 17:11:21 UTC 2021

Erik,

When I was working at my last (pre-retirement) job, I encountered an old
PRS-10
gathering dust.  It worked well free-running, but when I tried to lock it
to 1PPS,
it would do nothing for a while, then would begin deviating further and
further
from a correct lock.  Over a period of a few hours it would basically run
amok.

Dana

On Thu, Jan 7, 2021 at 10:10 AM <e.j.kroon at vathorstnet.nl> wrote:

> Hi All,
>
> I have done an experiment using the PSR10.
> I have set the Magnetic offset to mid-range MO2950
> Than set the Set frequency to 0 SF0. To have 0 frequency offset.
> Measured the output frequency and calculate the average deviation.
> By using the Frequency Synthesizer Table from Appendix A I have selected
> the
> smallest frequency deviation by changing via the Frequency Synthesizer
> Control command SP.
> Than measured the frequency deviation again and use the Set frequency
> command for
> the correction of the deviation (by SF). By monitoring the Magnetic read
> you
> are able to see
> the Magnetic C field effect from the SF setting. Than enter the Magnetic
> offset to the value of
> magnetic read via MO. Finally set the SF to 0.
> By this procedure the frequency deviation is < than a few parts to -12.
> And within the Magnetic offset range.
> However still the 1pps control is not working and stops the internal time
> interval.
> Maybe by corrupted eprom TO setting.
> But the unit is good for un-steered operation.
>
> Thanks for your help
>
> Erik (PE1RQF)
>
>
>
> -----Original Message-----
> From: time-nuts <time-nuts-bounces at lists.febo.com> On Behalf Of Dana
> Whitlow
> Sent: maandag 4 januari 2021 21:02
> To: Discussion of precise time and frequency measurement
> <time-nuts at lists.febo.com>
> Subject: Re: [time-nuts] PRS10 not locking to 1PPS
>
> Erik, the PRS-10 does have provisions for changing the internal
> synthesizer's "ratio",  which could provide a way of getting an essentially
> fresh start on aging.
> There's a
> big table of values somewhere in the documentation (but not necessarily in
> any convenient order).
>
> My old PRS-10 is getting towards one end of its magnetic tuning range and
> will probably "die" in another couple of years use, but I have high
> expectations of winning it back via this mechanism.
>
> Have you looked into this?
>
> Dana
>
>
> On Mon, Jan 4, 2021 at 1:36 PM <e.j.kroon at vathorstnet.nl> wrote:
>
> > Hi all,
> >
> > The PSR10 is working now for 15 years at my place (total >25 years).
> > For the 1pps a Trimble Resolution T is used and has a good 1pps signal.
> > The Magnetic Offset MO is on the limit value of 2300 when using the
> > 1pps correction.
> > Therefore I think the unit is on end of life. I tried a factory reset
> > to see what will happen.
> > However due to the change of the TO to 1814 the unit stopped measuring
> > the 1pps time pulses after 256 measurements and no 1pps measurement
> > are possible when PL=1.
> > The other values are responsive. Only after a RS1 it will measure
> > again the pps.
> > My thought was due to the strange TO of 1814 (before factory reset is
> > was
> > -1814)
> > the internal calculation is messed up.
> > When PL=0 the pps measurements continues but the MO is not controlled
> > to GPS.
> > I am not sure how to update the firmware.
> > While the unit is still stable, it has now an frequency offset of
> > -2.7E-10 Hz/Hz stability still is
> > 2.4E-12 for 20k seconds.
> > Probably I need another rubidium frequency standard.
> >
> > ST5 when PL=0
> > 3 = PPL disabled,  < 256 good 1pps inputs Provide stable 1pps inputs
> >
> > ST5 when PL=1 and when 1pps hangs
> > 4 = Excessive time interval (while 1pps is still good of the GPS)
> >
> > Regards,
> > Erik (PE1RQF)
> >
> >
> >
> >
> > -----Original Message-----
> > From: Miikka Raninen <miikka.raninen at gmail.com>
> > Sent: zondag 3 januari 2021 21:44
> > To: time-nuts at lists.febo.com
> > Cc: e.j.kroon at vathorstnet.nl
> > Subject: PRS10 not locking to 1PPS
> >
> > > Hello Time-Nuts,
> > >
> > > I am an user of a PRS10 Rubidium standard.
> > > The unit has firmware revision 3.15.
> > > After reset to factory settings the Time Offset (TO) was set to 1814.
> > > Normally it was -1814. Now de PRS10 is not locking to the 1PPS anymore.
> > > It will freeze when PL = 1. It will freeze after 256 seconds.
> > > Is there a known way to set the TO back to -1814 for the firmware
> > revision?
> > > As it is a factory setting for this firmware revision.
> > >
> > > Regards,
> > > Erik pe1RQF (former time keeper for the Netherlands at VSL)
> >
> > Ref manual for PRS10 :
> > https://www.thinksrs.com/downloads/pdfs/manuals/PRS10m.pdf
> >
> > Check the quality of the input 1PPS. When the unit fails to lock on to
> > 1PSS input after 256 seconds it is usually due to the 1PPS being too
> > unstable in phase
> >
> > What do you mean by freezing? Can you check the status bytes with ST?
> > command? They might indicate the reason for the fault :
> >
> > ST5: Frequency Lock to External 1pps
> > ST5 bit Condition which sets bit Corrective Action
> >
> > 0 PLL disabled Send PL 1 to enable
> > 1 < 256 good 1pps inputs Provide stable 1pps inputs
> > 2 PLL active
> > 3 > 256 bad 1pps inputs Provide stable 1pps inputs
> > 4 Excessive time interval Provide accurate 1pps
> > 5 PLL restarted Provide stable 1pps inputs
> > 6 f control saturated Wait, check 1pps inputs
> > 7 No 1pps input Provide 1pps input
> >
> > You might also want to consider updating the firmware as "(Note:
> > Firmware revisions prior to Rev 3.23 do not allow user TO! commands.
> > Check the firmware revision with the ID? command)"
> >
> > - Miikka Raninen OH3GPJ
> >
> >
> > --
> > This email has been checked for viruses by AVG.
> > https://www.avg.com
> >
> >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at lists.febo.com To unsubscribe, go
> > to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
> >
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
>
> --
> This email has been checked for viruses by AVG.
> https://www.avg.com
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>