Manual
KVCG202/EN M/H
7.5 Setting control
Control functions via a KVGC202 relay can be performed over the serial communication
link. They include change of relay settings, change of setting groups, remote control of
the operating modes.
Remote control is restricted to those functions that have been selected in the relays menu
table and the selection cannot be changed without entering the password.
CRC and message length checks are used on each message received. No response is
given for received messages with a detected error. The Master Station can be set to
resend a command a set number of times if it does not receive a reply or receives a reply
with a detected error.
Note: Control commands are generally performed by changing the value
of a cell and are actioned by the setting change procedure, as
described in Chapter 7.3.1, and have the same inherent security.
No replies are permitted for global commands as this would cause
contention on the bus; instead a double send is used for
verification of the message by the relay for this type of command.
Confirmation that a control command, or setting change, has been
accepted is issued by the relay and an error message is returned
when it is rejected.
The command to change setting group does not give an error
message when the group 2 settings are disabled unless link
SD3=0 to inhibit response to a remote setting group change
commands.
7.5.1 Remote setting change
The relay will only respond to setting change commands via the serial port if link SD1=1.
Setting SD1=0 inhibits all remote setting changes with the exception of the SD software
links and the password entry. Thus, with link SD1=0, remote setting changes are
password protected.
To change them, the password must be remotely entered and the function link SD
function link SD1 set to “1” to enable remote setting changes. When all setting changes
have been made set link SD1=0 to restore password protection to remote setting
changes.
7.5.2 Remote control of setting group
The setting group selection is fully described in chapter 5, Chapter 5.2 including the
remote control of this function. Group 2 must be activated before it can be selected by
setting software link SD4=1. Set link SD3=1 to enable the relay to respond change
setting group commands, via the serial port to select group 2 and set SD4=1 to inhibit this
function.
If the remote setting changes have been selected to have password protection, as
described in Chapter 7.5.1, then it can also be applied to the remote setting group
selection as follows. Set link SD3=0 to inhibit remote setting changes, then set link
SD1=1 to enable remote setting changes and set link CTL2=1. The group 2 settings will
then be in operation and setting link SD1=0 will restore the password protection.
If conventional SCADA has an output relay assigned to select the alternative setting
group then it may be used to energise a logic input assigned in the input mask [070A
STG GRP 2]. In this case set link SD3=0.
7.6 Loadshedding/boosting control
7.6.1 Remote control of loadshedding/boosting
The KVGC202 relay responds to the loadshedding/boosting by level Courier commands.
These commands are used to control the level of loadshedding/boosting of the KVGC202
relay. The relay retains the selected level until new command is received or an opto input
is energised, which overrides the command over the serial port. The settings are stored
by the relay when the relay is powered-down and restored again on power-up.
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