ABB REM 610 Technical Reference Manual page 70

REM 610 Motor Protection Relay 1MRS 755537
Technical Reference Manual
If a UDR is linked to a non-existent holding register, reading from the register will
fail and an "Illegal address exception" response will be sent. Giving the link address
the value 0 will disable the UDR. If the master reads from a disabled UDR, the value
0 will be returned.
The UDRs are mirrored in HR385...400.
Fault records
The data recorded during a fault sequence is called a fault record (FR). The slave
stores the five latest fault records. When a sixth record is stored, the oldest record
will be deleted. To read a fault record:
1. Write a preset single register command (function 06) to HR601 using a selection
code as data value.
2. Read the selected fault record (function 04) from HR601, register count 33.
Alternatively, a fault record can be read using one command (function 17H) only.
Selection code 1: The master reads the oldest unread record
Status register 3 (HR403) informs whether there are unread fault records (see Fig.
4.1.14.2.-2). If there is one or several unread fault records, the master can read the
contents using selection code 1.
The fault record contains a sequence number which makes it possible for the master
to determine whether one or several unread fault records have been deleted due to
overflow by comparing it to the sequence number of the previously read fault record.
The slave keeps track of which fault record is currently the oldest unread. The master
can continue reading fault records for as long as Status register 3 indicates that there
are unread records.
Special case 1: If there are no unread fault records, the contents of the last read
record will be returned. If the buffer is empty, however, the registers will contain
only zeros. This is the only time when sequence number zero will appear.
Special case 2: If the master tries to read the next unread fault record without
entering selection code 1 again, the contents of the last read record will be returned.
Selection code 2: The master reads the oldest stored record
By resetting the read pointer using selection code 2, the master can read the oldest
stored fault record. After this, the master can continue reading the following records
using selection code 1, irrespective of whether they have been read before.
Note!
Resetting the read pointer will not affect the sequence number of the fault record.
Note!
A master reset, i.e. clearing of targets and memorized values and unlatching of
output contacts, will clear the fault records, after which the sequence number will
start from 1 again.
Event records
Modbus events are derived from SPA events. With a few exceptions, SPA events
update binary points in the DI and the packed HR area. Simultaneously, a
corresponding Modbus event record will be generated. The event record contains the
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