Siemens SIPROTEC 6MD665, Руководство пользователя

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2.8 Inter relay communication
69
6MD665 Manual
C53000-G1876-C103-3
2.8 Inter relay communication
Inter relay communication, abbreviated IRC, allows the exchange of information
between SIPROTEC
®
4 devices without a SICAM SAS control centre. For this pur-
pose, the devices are connected to each other via an RS485 connection or via an
external converter and fibre optic cable. Process information such as indications and
measured values (RMS values) are transferred via this bus.
Configuration of the Inter relay communication is performed with the DIGSI
®
operating
program.
Communication works cyclically on the basis of an image protocol. The cycle time is
constant in fault-free operation and dependent on the baud rate, the amount of
process information and the number of connected devices. All SIPROTEC
®
4 devices
which communication which each other are called users of an IRC combination. An
IRC combination can handle a maximum of sixteen users.
Usecases An Inter relay communication setup always makes sense if the same process infor-
mation needs to made available to several SIPROTEC
®
4 devices. Instead of
sending the same process information to several SIPROTEC
®
4 devices per single
line wiring, it is only sent to a single SIPROTEC
®
4 device. The other SIPROTEC
®
4 devices receive the required process information via the serial IRC bus.
An application for the Inter relay communication could be the interlocking conditions
within a bay with a 1
1
/
2
–circuit breaker method operated with three bay controllers.
The OLM (Optical Link Module) interface modules required for an optical connec-
tion of the IRC user can be found in the accessory list in the Appendix.
Requirements Certain requirements must be fulfilled to build an IRC combination
The participating SIPROTEC
®
4 devices must be suited toward Inter relay communi-
cation.
A corresponding communications module must be installed in the SIPROTEC
®
4
devices.
The DIGSI
®
operating program must be installed on the PC.
The project must contain at least two SIPROTEC
®
4 devices which fulfill the require-
ments for Inter relay communication and an IRC combination (can be created via con-
figuration).
2.8.1 Description
Function principle The IRC is based on the Master-Slave principle. One SIPROTEC
®
4 device of the
IRC combination operates as the master. All other users are slaves. The master sends
queries to all the slaves one after the other. On receiving this query, each slave trans-
mits its particular process information meant for the IRC combination. The master col-
lects all the process information it receives and collates it, together with its own infor-
mation, into a single message. It then sends this message to all the slaves. From this
message, each slave then extracts the process information which is relevant to the
particular slave.