Specifications

7SR242 Duobias Data Communications
©2010 Siemens Protection Devices Limited Chapter 4 Page 11 of 43
Section 3: IEC 60870-5-103 Definitions
3.1 Introduction
This section describes the IEC 60870-5-103 protocol implementation in the relays. This protocol is used for the
communication with REYDISP software and can also be used for communication with a suitable control system.
The control system or local PC acts as the master in the system with the relay operating as a slave responding to
the master’s commands. The implementation provides event information, time synchronising, commands and
measurands and also supports the transfer of disturbance records.
This protocol can be set to use any or all of the relays hardware interfaces (USB, Fibre Optic and RS485) and is
the standard protocol used by the USB port. The relay can communicate simultaneously on all ports regardless
of protocol used.
Each relay must be given an address to enable communication and can be set by the Communication
Interface:Relay Address. Valid settings are within the range 1 – 254, a relay with the default address of 0 will not
be able to communicate.
Cause of Transmission
T
he cause
of transmission (COT) column of the ‘Information Number and Function’ table lists possible causes of
transmission for these frames. The following abbreviations are used:
Abbreviation Description
SE spontaneous event
T test mode
GI general interrogation
Loc local operation
Rem remote operation
Ack command acknowledge
Nak Negative command acknowledge
Note: Events listing a GI cause of transmission can be raised and cleared; other events are raised only.
Function Type
Abbreviatio
n Description
1 Time tagged message (monitor direction)
2 Time tagged message (relative time) (monitor direction)
3.1 Measurands I
4 Time-tagged measurands with relative time
5 Identification message
6 Time synchronisation
7 General Interrogation Initialization
9 Measurands II
20 General command
Information Number and Function
The following table lists information number and function definitions together with a description of the message
and function type and cause of transmission that can result in that message. Definitions with shaded area are not
available on all relay models.