ABB NPCT-01C Inverter Pulse Counting/Timer Unit Assembly
With this concept the RTU560 fulfills the highest
availability requirements.
Technical features
• Redundant communication lines or links;
communication via 2 communication lines in
a parallel mode (multi host with all available
protocols) or in an active/standby switchover
mode (redundant line/network with IEC 60870-
5-101/104)
• Redundant CMU performance;2 sets of CMU
boards in an active/standby switchover mode
• Redundant power supply 2 redundant power
supply;boards for the supply of the communica tion subrack
Due to modular architecture of the RTU560 it is
possible to use parts or combination of the redun dancy elements.
Time Synchronization
The accuracy and resolution of the time stamp for
a process event is important for analysing a process
disturbance,especially when it is necessary to ana lyse events from and between different stations.
The RTU560 meets this requirement.The internal
time management is controlled by the CMU com munication boards.
The time resolution of the RTU560 is 1 ms for
events,scanned by the directly connected I/O
boards.Synchronization with absolute time can b

achieved by one of the following four methods:
• Time synchronization by the network control
center (NCC) via a periodically transmitted syn chronization instruction with a communication
protocol supporting this function
• Time synchronization using a real-time clock that
receives the date and time from the GPS system
• Time synchronization using a real-time clock that
receives date and time information from the
DCF 77 time standard
• Time synchronization using SNTP V4 (RFC2030)
on a LAN/WAN network
The RTU560 time management system synchro nizes the RTU with the supplied absolute time
with a high degree of accuracy.The absolute
accuracy is mainly provided by the source for
synchronization used,whereby GPS and DCF 77
allow an accuracy of 5 ms and better.The accuracy
of time synchronization by the NCC depends on
transmission speed,and the method used within
the NCC
A time synchronized RTU560 can synchronize sub ordinate RTUs and IEDs via:
• a periodically transmitted synchronization
instruction with a communication protocol
supporting this function
• Time synchronization using SNTP V4 (RFC2030)
on a LAN/WAN network
Special hardware and software logic with a high
control quality has been incorporated on each of
the CMU communication boards to manage real
time within the RTU560.Once the RTU560 is syn chronized,the
RTU560 can maintain a time accu racy of about 2 PPM,even if the time synchroni zation source is lost for a certain period.