FS22DI
OPERATION
18
Ethernet
Switch
NTP
NTP
NTP
NTP Server
Fig. 3.11
Synchronizing interrogators with conventional technology
Synchronization is again of extreme importance in such systems. When an NTP server is
running the Interrogator will start synching as soon as a first communication from the
server is received.
For details on the other equipment please refer to their respective user manuals.
Synchronization process
Each interrogator synchronizes its internal clock with the NTP server. Upon starting, all
devices and the NTP server need some settling time to achieve the best synchronism
possible.
The following features for NTP synchronization are available:
Number of devices to be
synchronized
Unlimited
Synchronization accuracy
100 μs to 10 ms
Synchronization settling
time
Up to 30 min during first start, up to 2 min during restart
Synchronization master
External SyncMaster, e.g. PC
For a good synchronization, the dedicated NTP server should run continuously. The accu
racy is described by the two values:
S
Offset: average deviation from time server
S
Jitter: typical variation range of the offset value
The clock synchronization is classified using the following offset intervals:
S
<500 μs: excellent
S
<1 ms: very good
