I am trying to get SNTP to work on a pm573-eht.
I get it to sync against my IT department's SNTP server but only in GMT. I live in sweden (GMT+1) and we have daylight sving so the result is that my PLC is 2 h late.
I am new to this SNTP and NTP but can i suggest that my IT department edit (or add) server to sync swedish time or do i have to do a special program in the PLC to compensate.
Then the question is how do i build a reliable program to fix the time, remember we have daylight saving so it is a bit complex.
I have about 25 AC500 installations that need to be able to timestamp events..
i have got the timestamp thing to work, now i just need the correct time..
Voted best answer
Your PLC is behaving as expected.
SNTP always synchronizes to UTC (Universal Time Corordinate) which is basically the same as GMT. So No, You cannot get your IT department to make an SNTP time source in a different time zone. There is no such thing.
Even though in your project all your PLC's are in the same timezone you should never assume this to be true. For this reason, standard practice is for timestamps to always be in UTC. Your AC500 Real Time Clock also tracks UTC.
AFAIK the AC500 does not have in built TimeZone settings to enable a Local Date/Time inside the PLC. So the Local Date Time needs to be displayed on the HMI by converting from the System Date/Time using the HMI's local time zone. (Again, because your HMI could be in a different Timezone from your PLC, then it actually makes sense to do it this way)
In the CoDeSys visualization this is done by using a Text display with the format %t ( for time ), %x (local date), %X (local time), %z or %Z for Timezone . See the CoDeSys help file for details.
In Panel View 600 there is a setting for the Panel's Local Time Zone in system settings, which should be supported by the Date Time Widget. Again, see the help files.