ABB 615 Series ANSI Manual page 47

1MAC052634-MB D
615/620 series ANSI
Communication Protocol Manual
Other fault record registers
Sequence number
Every fault record is given a sequence number. The sequence number runs from 1 to 65535
and then rolls over to one again. The client can check that the sequence numbers of the
recorded data are sequential. During the fault record buffer overflow the client can notice
a jump in the sequence numbers when some fault records are lost. The gap between the
new and the previous sequence number reveals exactly how many records have been lost.
Unread records Left
This register shows how many unread fault records still remain unread for the client in
question at a particular moment.
Time stamp registers
The time stamp registers usually hold two data values in the high and low byte of the
registers. High byte value = RegisterValue DIV 256, Low byte value = RegisterValue
MOD 256. An exception is the milliseconds register which contains the milliseconds
0...999 coded as such. Time stamp also contains a time quality register.
Time quality
Table 30: Information contained by the 16 bit (bits 15..0) register
Bit Meaning
15 Event time stamp format
14 Time stamp source
13 Clock not synchronized
12 Clock failure
11...0 Reserved
Event time stamp format bit 15
The time stamp format can be selected with a Modbus parameter via the LHMI or the
parameter setting tool.
Event time stamp source bit 14
The time stamp can be generated by the IED application, that is accurate time, or by
Modbus. If generated by Modbus, the change values are detected by the Modbus
background scan task. Since there is a latency time between the value change and the time
when Modbus detects the change, in this case the time stamp is not accurate.
Clock not synchronized bit 13
The quality information bit is set in the IED's real-time clock if the IED has not been
synchronized.
Vendor-specific implementation
Values
0 = Local time 1 = UTC time
0 = Internal 1 = Modbus stack
application
0 = Synchronized 1 = Time not
synchronized
0 = Clock OK 1 = Clock failure
0
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