Siemens SINUMERIK 840DE sl Commissioning Manual page 1344

Configuring the system
2.3 Configuration file "basesys.ini"
Synchronizing the time
You must distinguish between the following cases when synchronizing the time:
● If there is an external NTP server to act as a time server (entered in the basesys.ini file or
via DHCP), then the PLC clock is synchronized via the Linux clock.
● If there is no external time server, the PLC clock will be the master for the Linux clock:
With "memory reset" the time of the PLC clock remains intact and is not reset. If the PLC
is switched on in switch position 3 "MRES" then the time will be reset. In this case the valid
time is taken over from the Linux system and does not need to be reset.
You can obtain information about the NTP server using the following command: sc ntpdiag
(Page 50)
NOTICE
Restriction on time synchronization
Do not set the time synchronization on two different systems; this means:
Select the NTP server either in the PLC project via PROFINET IO (X150) or in the
"basesys.ini" on the NCU in section [LinuxBase], but not in both simultaneously, as an
additional time zone can be specified on the NCU - however, not in the PLC project.
Timezone
The time zone set here is used by the system to convert UTC time (Universal Time
Coordinated) to local time. The time zone is sent to all applications via the environment variable
"TZ", and is taken into account by the libc function localtime().
The time zone influences all time entries in the basic system, particularly for the command
"date", for "ls -l", and in the system log file /var/log/messages.
Value:
Default:
Examples:
If the control is to synchronize with one of the listed time zones, the examples in the table can
simply be copied.
Zones with daylight saving time/standard time:
Europe:
USA:
Zones without daylight saving time/standard time:
26
Time zone description (see syntax and examples)
UTC
WET0WEST,M3.5.0,M10.5.0/3
CET-1CEST,M3.5.0,M10.5.0/3
EET-2EEST,M3.5.0,M10.5.0/3
EST5EDT,M4.1.0,M10.5.0
CST6CDT,M4.1.0,M10.5.0
MST7MDT,M4.1.0,M10.5.0
PST8PDT,M4.1.0,M10.5.0
Commissioning Manual, 12/2017, 6FC5397-1DP40-6BA1
NCU operating system