ABB Relion REC670, Applications Manual

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The binary input controlling the function is defined in ACT or SMT. The CHNGLCK
function is configured using ACT.
LOCK Binary input signal that will activate/deactivate the function, defined in ACT or SMT.
GUID-8C333BC0-AA7A-4ED1-A772-18C22E8EEE62 v5
When CHNGLCK has a logical one on its input, then all attempts to
modify the IED configuration and setting will be denied and the
message "Error: Changes blocked" will be displayed on the local HMI;
in PCM600 the message will be "Operation denied by active
ChangeLock". The CHNGLCK function should be configured so that it
is controlled by a signal from a binary input card. This guarantees that
by setting that signal to a logical zero, CHNGLCK is deactivated. If
any logic is included in the signal path to the CHNGLCK input, that
logic must be designed so that it cannot permanently issue a logical one
to the CHNGLCK input. If such a situation would occur in spite of
these precautions, then please contact the local ABB representative for
remedial action.
22.4 Denial of service SCHLCCH/RCHLCCH
22.4.1 Application
GUID-64F4D905-9F73-4073-B8F6-8D373155316A v5
The denial of service functionality is designed to limit the CPU load that can be
produced by Ethernet network traffic on the IED. The communication facilities must
not be allowed to compromise the primary functionality of the device. All inbound
network traffic will be quota controlled so that too heavy network loads can be
controlled. Heavy network load might for instance be the result of malfunctioning
equipment connected to the network.
The functions Access point diagnostics function block measure the IED load from
communication and, if necessary, limit it for not jeopardizing the IEDs control and
protection functionality due to high CPU load. The function has the following denial of
service related outputs:
1MRK 511 401-UUS A
Section 22
Security
Bay control REC670 2.2 ANSI 605
Application manual