On Thu, Feb 19, 2015 at 12:48:46PM +0000, Rob wrote: > I am still finding out what sensor is best to use, we do have a room > temperature sensor that has .1C resolution and is readable via snmp, > and there are the usual sensors for board- and inlet air temperature. > (and of course CPU temperature) > > It does not matter if it is only a course indication, the room temperature > varies over a -10 .. 50C range (don't ask...) and a 1C resolution is not > bad relative to that.
In my tests using a sensor with 1C resolution it was barely useful with NTP sources and 1024s polling interval. If the sensitivity is around 0.1 ppm per degree, 1C resolution means the compensation jumping the frequency in 0.1ppm steps. That's a lot, especially if you compare it to the tracking skew with a refclock. I'd probably try a shorter polling interval first and maybe get a PPS with higher rate if possible to minimize the swings due to temperature changes. -- Miroslav Lichvar _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
