7SR242 Duobias Description Of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 52 of 52
6.7.1 Time Synchronisation – Data Comms
Where the data comms channel(s) is connected to a dedicated substation automation system the relay can be
time synchronised using the relevant command within IEC 60870-5-103 or optional DNP3.0 protocols. The time
can also be synchronised from ‘Reydisp Evolution’ which utilises the communications support software.
6.7.2 Time Synchronisation – Binary Input
A binary input can be mapped Clock Sync from BI. The seconds or minutes will be rounded up or down to the
nearest value when the BI is energised. This input is leading edge triggered.
6.7.3 Time Synchronisation – IRIG-B (Optional)
A BNC connector on the relay rear provides an isolated IRIG-B time synchronisation port. The IRIG-B input
expects a modulated 3-6 Volt signal and provides time synchronisation to the nearest millisecond.
6.8 Settings Groups
The relay provides eight groups of settings – Group number (Gn) 1 to 8. At any one time only one group of
settings can be ‘active’ – SYSTEM CONFIG>Active Group setting.
It is possible to edit one group while the relay operates in accordance with settings from another ‘active’ group
using the View/Edit Group setting.
Some settings are independent of the active group setting i.e. they apply to all settings groups. This is indicated
on the top line of the relay LCD – where only the Active Group No. is identified. Where settings are group
dependent this is indicated on the top line of the LCD by both the Active Group No. and the View Group No.
being displayed.
A change of settings group can be achieved either locally at the relay fascia, remotely over the data comms
channel(s) or via a binary input. When using a binary input an alternative settings group is selected only whilst the
input is energised (Select Grp Mode: Level triggered) or latches into the selected group after energisation of the
input (Select Grp Mode: Edge triggered).
6.9 Password Feature
The relay incorporates two levels of password protection – one for settings, the other for control functions.
The programmable password feature enables the user to enter a 4 character alpha numeric code to secure
access to the relay functions. The relay is supplied with the passwords set to NONE, i.e. the password feature is
disabled. The password must be entered twice as a security measure against accidental changes. Once a
password has been entered then it will be required thereafter to change settings or initiate control commands.
Passwords can be de-activated by using the password to gain access and by entering the password NONE.
Again this must be entered twice to de-activate the security system.
As soon as the user attempts to change a setting or initiate control the password is requested before any changes
are allowed. Once the password has been validated, the user is ‘logged on’ and any further changes can be
made without re-entering the password. If no more changes are made within 1 hour then the user will
automatically be ‘logged off’, re-enabling the password feature.
The Settings Password prevents unauthorised changes to settings from the front fascia or over the data comms
channel(s). The Control Password prevents unauthorised operation of controls in the relay Control Menu from the
front fascia.
The password validation screen also displays a numerical code. If the password is lost or forgotten, this code
should be communicated to Siemens Protection Devices Ltd. and the password can be retrieved.
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