KROHNE Summit 8800 Vol 3 - Manual (Page 24)

24 www.krohne.com 08/2013 - MA SUMMIT 8800 Vol3 R02 en
SUMMIT 8800 DATE & TIME 04
4 .2 SNTP Time Synchronisation
The SNTP or Simple Network Time Protocol is available to synchronise the internal clock with a
network time server. While the internal clock’s accuracy is limited to about 3 ppm/°C, these time
servers are based on atomic clocks to guarantee the best accuracy. This function also ensures
that all flow computers in a network are using the same time.
The flow computer works with time servers using version 3 or 4 of the SNTP protocol, either
Unicast or Broadcast:
• Unicast is where the flow computer will request the time from a specified time server.
• Broadcast is when the flow computer waits for a broadcast packet from a time server, and
then confirms the results by using a unicast request.
The SNTP can be setup in the hardware section under the Ethernet SNTP:
Figure 7 SNTP Date & time general settings
Enable Click the box to enable SNTP
Operating mode Set the mode as unicast or multicast
Port The port used for SNTP standard specifies that this should be 123.
Min time adjustment Minimum amount of time the flow computer clock can be adjusted
Max time adjustment Maximum amount of time the flow computer clock can be adjusted
Max time without adjustment Maximum number of seconds that the flow computer can be expected
to operate without receiving a new time from the time server. If this time
is exceeded without receiving a new time then the flow computer will
give a warning.
Invalid time update limit Maximum number of bad updates that can be received before a warning
is given.
Ignore max adjust on startup Indicates if the maximum time adjustment value should be ignored for
the first valid time received by the flow computer after power up.
Offset from GMT The time zone of the local time as an offset from the atom clock +/-
GMT minutes