ABB UniGear Series, Engineering Manual

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Figure 88: Example of an allocation of device IP addresses
3.5.7 Time synchronization
Accurate time synchronization with precision requirements of sub one microsecond is essen-
tial for a proper functionality of process bus. Sampled measured values need to be synchro-
nized between the sending and the receiving protection relays that perform protection or
control functions. The 615, 620 and 640 series support the IEEE 1588 (PTPv2) protocol and
Power Profile as defined in IEEE C37.238 to reach required timing accuracy over an Ethernet
network. Using the Ethernet network to propagate the timing signals eliminates extra ca-
bling requirements.
Figure 89: Example of IEEE 1588-time synchronization via the Ethernet network