Time difference between Alarm and Trend in WinCC

Dear Expert,

We are facing a problem that there is a difference of 04 minutes between Alarm and Trend in WINCC.

Trend Time is similar with server time but Alarm pop up at the same time, but in Alarm list time difference occurred and Alarm time lag 4 minutes than trend time

PLC= PCS7 v8.2 with S7-400,Cemat Library

WinCC v8.2

Regards

Malix

Hello Malix,

the question is, to you use "Bit-Messages" or "chronological messaging".

see FAQ:
"How do you implement chronological messaging with S7-400 CPUs and WinCC?"

https://support.industry.siemens.com/cs/ww/en/view/23730697

With "Bit-Messages" the timestamp is generatet by WinCC, when it recognices
the edge of the messagebit.
With "chronological messaging" the timestamp is send by the PLC via telegram.

Similar is it with "normal" Taglogging and "process-driven archiving of process values"

see FAQ:
"How do you use SFB37 (AR_SEND) for process-driven archiving of process values
in WinCC Tag Logging archives?"

https://support.industry.siemens.com/cs/ww/en/view/23629327

Regards

Georg Berghof

Hello Malix

Georg is right.

The standard library in PCS7 uses program alarms (alarm_8p) so the alarms will be time stamped with the cpu time, so you will need to synchronize the cpu time and pc time.

Dear Micheal,

Please guide how we will do this in our running system??

Hi HAMEEE,

you can find a step for step introduction how to configure the time synchronization in the manual Time Synchronization at the chapter Configuring time synchronization on an AS and Configuring the time synchronization for PC stations with OS.

With regards
Heisenberg