On 23 November 2010 05:17, John Kasunich <jmkasun...@fastmail.fm> wrote: > > Do you have internet access at the site? > > If you are running an PC for EMC, you can use NTP to keep > the PC's clock synced to the rest of the world
Doesn't it need to be synched to mains frequency rather than absolute time? How accurate is NTP (or even GPS time) in this context? ... <google> http://gpsinformation.net/main/gpstime.htm seems to think that is it close enough. However, what is really needed is to keep synch with the local mains during outages, and that might be better done by a local clock. You could potentially use siggen with a PID to correct phase, then lock the PID when mains voltage is lost. PID dosn't have a "lock" pin, so you would probably need to use a sample_hold. When the mains comes back you could use the PID to bring the generator back in to phase before switching back over. (and it probably wouldn't drift that much anyway) -- atp ------------------------------------------------------------------------------ Increase Visibility of Your 3D Game App & Earn a Chance To Win $500! Tap into the largest installed PC base & get more eyes on your game by optimizing for Intel(R) Graphics Technology. Get started today with the Intel(R) Software Partner Program. Five $500 cash prizes are up for grabs. http://p.sf.net/sfu/intelisp-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
