time sycnhronisation in 800xA with GPS
As I understand that 800xA System can be synced with GPS using SNTP server. I understadn that we can use windows SNTP server and whole 800xA system can be synced with this SNTP as indictaed in 800xA Manuals.
My question is what is protocol used between SNTP server and GPS clock. Do we need to run some utlity in computer to convert time from GPS to time in SNTP.
PLease see the attachment.
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This depends on your GPS hardware.
But the AC800M controllers can handle different protocols, like CNCP (default), SNTP, MMS and MB300.
This can be set through the "CS protocol type".
In this case, if the GPS clock "talks" one of these time sync protocols, it can be directly connected to the control network of the controller(s)
See also attached document as of page 28, 29 en 30.
I believe that most modern GPS time receivers have two ports:
- Coax to GPS antenna on the roof of the building
- RJ45 ethernet.
In the above case, the protocol you asked for is not known. The GPS can be integrated in a mini computer embedded with a with Ethernet port and SNTP server.
In the past most GPS units supported the serial NMEA (https://en.wikipedia.org/wiki/NMEA_0183) protocol.
Then a computer with a serial port could ask the GPS to periodically send NMEA sentences containing GPS time and adjust the computer clock accordingly.
I can recommend first to synchronize your 800xA server to GPS time, usually the GPS receivers have own tool for that - like if you connect this GPS to normal PC with windows.
You may be need to adjust Windows Time service for that. As usual, it is set to Internet time provider - please change to your GPS.
For Windows standard automatic update time from external source is 1 week !!!
You can adjust it in registry:
DWord entry "SpecialPollInterval" = seconds as decimal value
Then you can distibute the time from the Server to all nodes by means of 800xA protocols - how you prefere.
It is very easy. Of course you can do it in many other different ways.