Does Anybody Really Know What Time It Is?

I don't use have any experience using time in manufacturing but I did rely on time heavily in the NAVY.

I currently rely on N.I.S.T. for dimensional standards and information and recently discovered that N.I.S.T. and U.S.N.O. work together on time. COOL

Check out the NIST-F1 Cesium Fountain Atomic Clock.

http://www.boulder.nist.gov/timefreq/

http://tycho.usno.navy.mil/

And to the 2nd part of the phrase, "Does anybody really even care?"

If you can log on on internet, and go for NIST site, your machine can be in sync with NIST. I do it for Astronomical obesrvations.

If you need a relatively stable time signal, you can snag it from many GPS units.

There are some 'external time synchronizatoin devices' that are really GPS recievers that you can plug into your network. If a milisecond or so is good enough, using NTP over any kind of an internet link will work. Theoretically it is better than that. But GPS gives a more stable link.

The good thing about NTP is you can run your own time servers (at least 3 suggested by me) and have them sync to the NIST second level time servers. (first level servers should only sync second level, but lots of people ignore that, thinking it will help them get a 'better time'. From what I can tell, it does not.)

http://www.meinberg.de/english/products/lantime-m300-gps.htm -- I found this with a quick internet search. An NTP server appliance that also has a GPS receiver built in. No endorcement other than it superficially looks good. I am not affiliated in any way with this vendor or device.

I hope this was of some help.

We synchronize the clocks in the PLCs and HMI in our plant. This is not because we synchronize our processes or machines but it does help us in analyzing problems.

When we have an incident, we sometimes need to see the time relationship of the sequences of events. It helps us in determining root causes and in formulating solutions.

So far, we haven't had the need to keep the clocks synchronized to within three seconds which is about the limit to which we can keep them in sync.

Employees are much more demanding in requiring us to keep the clocks accurate. Everyone wants to clock-out at 5pm sharp!