Real Time Clock; Time Synchronisation - Data Communication Interface; Time Synchronisation - Binary Input; Settings Groups - Siemens 7SR157 Argus Manual

Energy management

6.6 Real Time Clock

Time and date can be set either via the relay fascia using appropriate commands in the System Config menu or

via the data comms channel(s). Time and date are maintained while the relay is de-energised by a back up

storage capacitor. The length of time for which this data will be maintained will depend on such things as

temperature, length of time in service, etc. However the data will be maintained for a minimum of 1.8 days.

In order to maintain synchronism within a substation, the relay can be synchronised to the nearest second or

minute using the communications interface, or a binary input.

The default date is set at 01/01/2000 to deliberately indicate that the date has not yet been set. When editing the

Time, only the hours and minutes can be edited. When the user presses ENTER after editing the seconds are

zeroed and the clock begins running.

6.6.1

Time Synchronisation – Data Communication Interface

Where the data comms channel(s) is connected the relay can be directly time synchronised using the global time

synchronisation. This can be from a dedicated substation automation system or from 'Reydisp Evolution'

communications support software.

6.6.2

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.

The relay provides four groups of settings – Group number (Gn) 1 to 4. At any one time only one group of settings

can be 'active' – SYSTEM CONFIG>Active Group setting. An output is provided to indicate which setting group

is active.

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).

Settings are stored in non-volatile memory.

Chapter 1 - 7SR157 Description of Operation

Chapter 1 - Page 37 of 38

Table of Contents