[time-nuts] PRS10 not locking to 1PPS

[Dana Whitlow]

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
>
>
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