[ntp:questions] Assistance with PPS on Windows

Ken Link klink at numberzero.org
Fri May 6 14:51:24 UTC 2011

Hi Martin,

We had considered using the time adjustment service from the driver
package at one point, but it seemed to conflict with NTP's
configuration at the time. If I disable NTP entirely and only use
MbgMon and it's time adjustment service, things look great and the
clock is synced to +/- 0.003s from the IRIG signal. However I can't do
that for two reasons:

1) I would like to share this highly accurate time as an NTP stratum 1
peer (as well as verify it's accuracy by running NTP with multiple
peers configured), but when I run NTP and the MbgMon time adjustment
service at the same time, NTP tries adjusting the clock and causes a
drift of a few hundred msec and high jitter because the two services
are fighting over the clock.

2) In the case where the IRIG signal fails or is inaccurate (e.g.
Arbiter clock becomes unlocked from GPS signal) there is no
redundancy, validation of correct time/clock discipline, or other time
server to connect to unless I am running NTP, which goes back to point

In a perfect world I could run MbgMon's time adjustment service and
NTP together (with multiple peers), NTP won't touch the clock until
the IRIG signal is determined to be bad (loss of IRIG signal, loss of
GPS signal at the clock, or local clock is rejected when compared to
other peers), and other peers can rely on this computer for accurate
and stable time via NTP.

Because we couldn't figure that out, we decided to give PPS a try. Is
there a way to configure NTP to play nice with MbgMon?


On Fri, May 6, 2011 at 8:20 AM, Martin Burnicki
<martin.burnicki at meinberg.de> wrote:
> Ken,
> Ken Link wrote:
>> Hello,
>> We have two 32 bit Windows XP SP3 machines here for testing an Arbiter
>> 1093C GPS clock and a Meinberg TCR511PCI IRIG card. Both systems are
>> running NTP 4.2.6p3 stable. System A is synced via serial port to the
>> Arbiter clock and is a stable Stratum 1 server. System B has the
>> Meinberg IRIG card and is currently having issues.
> Would you let me know *which* issues you are having with the card, or with
> the time adjustment service from the driver package?
> The advantage of PCI card is that programs can read the accurate time
> directly from the card at any time, there are no interrupt latencies. So
> the time adjustment service should keep the time as accurate as possible
> under Windows. If that does not work then it may be due to a configuration
> problem and it should not be too hard to solve this.
> Take care, I'm biased ;-)
> Martin
> --
> Martin Burnicki
> Meinberg Funkuhren
> Bad Pyrmont
> Germany
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