Siemens SIPROTEC 7SJ62 Manual page 23

Serial Interfaces
The Front PC Interface is provided for local communications with a personal computer using the DIGSI soft-
ware. This facilitates a comfortable handling of all device functions.
The Rear Service Interface can also be used to communicate with the relay from a PC running the DIGSI soft-
ware. This interface is especially well suited for a permanent connection of the devices to the PC or for oper-
ation via a modem. The service interface can also be used to connect an RTD box (= resistance temperature
detector) for obtaining external temperatures (e.g. for overload protection).
The Additional Interface (only 7SJ64) is designed exclusively for connection of a RTD-Box (= resistance tem-
perature detector) for obtaining external temperatures.
All data can be transferred to a central control center or monitoring system via the serial System Interface.
This interface may be provided with various protocols and physical transmission schemes to suit the particular
application.
A further interface is provided for the time synchronization of the internal clock via external synchronization
sources.
A range of communication protocols are available from a variety of additional interface modules.
The operator or service interface allows you to operate the device from a remote location or on site using a
standard browser. This is possible during commissioning, checking and also during operation of the devices.
The SIPROTEC 4 Standard „WEBMonitor" is available for this task.
Power Supply
A power supply unit (Vaux or PS) delivers power to the functional units on the different voltage levels. Voltage
dips may occur if the voltage supply system (substation battery) becomes short-circuited. Usually, they are
bridged by a capacitor (see also Technical Data).
SIPROTEC, 7SJ62/64, Manual
C53000-G1140-C207-2, Release date 01.2008
Introduction
1.1 Overall Operation
23