Internal Time Synchronization Via Rtc - Siemens SICAM MMU 7KG9663 Device Manual

8 Time Synchronization

8.4 Internal Time Synchronization via RTC

In these cases, SICAM MMU is not synchronized anymore. The device uses the internal clock (on milliseconds
time basis) and the last valid drift. After the programmable delay time, the device reports "Clock Error", see
chapter 14.
Switching Back from the Secondary to the Primary NTP Server
While the device is synchronized by the secondary NTP server, it continues to cyclically poll the primary NTP
server. The device will only switch back to the primary NTP server if it receives correct time information and if
none of the criteria for Redundant NTP Servers are fulfilled anymore.
NOTE
The chapter 7.3.4.1 gives a detailed description of how to parameterize the time. chapter 9.2.6.2 and
chapter 9.2.7.2 provide information on the data format.
8.4 Internal Time Synchronization via RTC
Besides external time synchronization, the internal time synchronization is also possible using the battery-buff-
ered RTC (Real Time Clock). SICAM MMU features a quartz oscillator for this purpose.
The time offset of internal time synchronization is 86 ms/day maximum. Due to the reduced accuracy, RTC
should only be used in case of failure or unavailability of the external time synchronization.
NOTE
The chapter 7.3.4.1 gives a detailed description of how to parameterize the time. chapter 9.2.6.2 and
chapter 9.2.7.2 provide information on the data format.
144 SICAM MMU 7KG9663, Device Manual
E50417-H1040-C514-A3, Edition 01.2016