Technical data

Fundamentals
2.4 Time synchronization in distributed PCS 7 plants
Time synchronization (V7.1)
Function Manual, 03/2009, A5E01216578-01
15
Rules for configuring distributed PCS 7 plants
Since PCS 7 plants generally operate on the basis of UTC internally, their specific
components can be distributed on a global scale. In order to safeguard the interplay of
components - even across different time zones - please observe the following:
● Use UTC as the common time base in all PCS 7 plants. All plant components running
with UTC will display the same time after time synchronization.
● Set up a PC station as a PCS 7 Web server in all PCS 7 plants, using the PCS 7 OS web
option. This will allow you to access the PCS 7 Web servers of the PCS 7 plants via
multiple Web clients (in PCS 7: WebNavigator client or WebNavigator diagnostic client) at
the company's headquarters. You can convert the time display on the Web client to the
local system time. Please note the resulting time difference.
● If monitoring a PCS 7 plant in a different time zone on an OS, you can convert the time
displayed from UTC to the local system time using the OS control panel. Please note the
resulting time difference.
Note the following to prevent external synchronization:
NOTICE
Time message frames from external networks
Time message frames from external networks must be prevented from infiltrating
process control systems that are distributed across several networks or connected to
the Intranet or Internet.
Always connect the company network and the plants using network components that
enable separation of time signals, e.g. a router. Configure those network components so
that forwarding of time message frames is blocked.
Further information
● Section "Setting the time displayed (Page 51)"
● WinCC online help