User's Manual

Siemens PLT 130
.
1994
4/13
Bus coupler
Description
Fig. 4/18 Bus coupler (BK--FF), subrack configuration
Application
Bus couplers are used for data transfer between participants on
independent remote buses (BK-FF). They enable decoupling of
the data transfer on the buses as well as distances between two
participantsupto3x4km.
The bus line can be single or redundant. Bus couplers can also
be used in parallel to increase the transmission performance. A
maximum of two bus couplers may be connected in series be-
tween two participants which exchange information.
Parallel bus
couplers
If the coupling capacity of a bus coupler is not sufficient, the
transmission performance can be increased by approx. 100%
by using a second bus coupler . This parallel connection of bus
couplers leads to limitations in performance if one of them fails
(this is not a redundant connection).
Redundant bus
couplers
If the coupling capacity of a bus coupler is sufficient, a redun-
dant system can be produced using a second bus coupler. In
this case, the second bus coupler automatically takes over the
coupling function if the first bus coupler fails.
Design
The bus coupler consists of
-- 2 interface modules for bus coupler (N-BK),
-- power supply module and
-- 2 or 4 bus converters UI for remote bus coupling (BK-FF)
depending on whether the remote buses are of single or
redundant design.
All these modules are fitted in a double-height subrack. This is
completely wired and equipped with all necessary plugs and
guide rails.
Mode of operation
A bus coupler acts like any other participant on the bus. It has
an address on every bus. A participant on bus 1 sends a mes-
sage to a participant on bus 2 by first addressing the bus cou-
pler. This stores the message briefly independent of the current
message transfer on bus 2 and acknowledges receipt to the
transmitting participant.
The bus coupler transmits the message on bus 2 if it becomes
the master on this bus. The participant to which the message is
addressed accepts the message and acknowledges receipt to
the bus coupler.
e. g.
Busaddress1
Participant address 5
e. g.
Busaddress1
Participant address 5
e. g.
Busaddress1
Participant address 6
e. g.
Busaddress2
Participant address 12
Redundant r emote bus 1
Redundant r emote bus 2
BK Bus coupler
UI Bus converter
Fig. 4/19 Parallel bus couplers, e. g. between redundant remote buses
Created with "Chameleon CMYK PDF Creator" for Wolfgang Strozyk at Siemens AG
This catalog is out of date, see note on page 2