1MAC052634-MB D
Section 3
Vendor-specific implementation
615/620 series ANSI
39
Communication Protocol Manual
Table 29:
Header part of the record structure
Fault record application data part
The data in the application section are IED type dependent. The description of the data is
found in the Modbus fault record section of the Modbus memory map.
Fault record reading
As long as there are unread fault records available for the Modbus client in question, bit 1
of the Modbus SSR3 register remains “1”.
The fault record reading is done in two steps. First, the client writes a selection code to the
Fault record selection register. The selection code defines the type of read operation that
the client wants to do. The selected fault record is loaded by the IED into the following N
registers (4xxxx-NNNN). See Modbus ANSI point list manual for specific fault record
structure mapping. Second, the client reads out these registers in one multiple register read
operation.
Fault record structure length
Since the application data part is IED type dependent, the length of the fault record
structures vary in different types of IEDs. A client can read out more Modbus registers
than are actually coded in one structure when reading out the data structures. The
maximum read amount is 80 Modbus registers. The additional trailing registers contain the
Address
1
1. See Modbus ANSI point list manual for specific event record structure mapping.
Register
Values
Comment
4xxxx
Fault record selection
1...4 and -1...-99
Write register
4xxxx + 1
Sequence Number
0...65535
4xxxx + 2
Unread records left
0...99
4xxxx + 3
TimeStamp (Year,Month)
High byte:year, low byte:month
4xxxx + 4
TimeStamp (Day, Hour)
High byte:day, low byte:hour
4xxxx + 5
TimeStamp (Min, Sec)
High byte:min, low byte:second
4xxxx + 6
TimeStamp (Milliseconds)
Word: milliseconds (0...999)
4xxxx + 7
Time quality
4xxxx + 8
From this location onwards starts the Fault record application data.
The fault records can be read by using two commands, the function 5 for
the write operation and the function 6 for the read operation, or by using
the function 23 that includes write and read operations in the same
transaction.
If the fault records are read by using two commands, the positive
confirmation to the write select operation tells the client that a fault record
has been loaded for reading. Another way to detect the positive
confirmation is by monitoring the state of SSR3 bit 9.
Summary of Contents for 620 Series ANSI
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