Hello everyone,

I have a problem with the system time on a S7-1200 using TIA Portal V16.0

When I use the 'Read System Time' (RD_SYS_T) block which returns the time in the DTL format, for some reason the 'hour' value is one hour less than what it should be.

For example when it is 08:00 on the PLC system time, the 'Read System Time' block will read  07:00 for some reason.

I have tried setting the PLC system time with the PC/PG interface which works correctly but it still leaves the hour value not right.

Anybody any suggestions?

Hi DS_7,

Try to use RD_LOC_T

Hello,

Maybe in hardware configuration selected summer adn winter time? then you got  + - 1 hour. Or you use set_timezone block to correct time.

DS_7

for some reason the 'hour' value is one hour less than what it should be.

The reason is that the system time is meant to be UTC. To get things right, you should set correct time zone in the PLC, align PLC time with your local time and use local time in a PLC as it was already mentioned.

Thanks for the replies everyone.

Ok so I am now using the 'read Local Time' block (RD_LOC_T) and have set the time zone in the device configuration under time of day to '(UTC) Dublin, Edinburgh, Lisbon, London'.

I am in the UK so this should be the correct time, but still the hour value is one hour behind when I read it?

How about Daylight Saving Time settings in properties of the CPU? Are they all OK?

And finally, is time zone and daylight saving time settings on your PC also correct?

Because what TIA is doing, it is checking local time and zone settings on your PC, then calculating UTC, setting PLC to UTC and finally PLC is calculating its own local time. So all blocks must match.

Hello DS_7,

after downloading the hardware configuration (with updated timezone) you may need to set the time on the PLC to current time. You can do this by going online to the PLC, open "Online & diagnostics" and go to Functions > Set time.

Regards,

Frink

New question published by Lev K. is split to a separate thread with the subject S7-1500 CPU Read System Time.

Best regards
Moderator_Lan