Siemens PLT130
.
1994

4/13

Bus coupler
Description
Fig.4/18 Bus coup ler (BK--FF),subrack configuration
Application
Bus couplers are used for data trans fer between participants on
independent remote buses (BK-FF). They enabl e decoupling of
the data transfer on the buses as well as distances between t wo
participantsupto3x4km.
The bus line can be single or redundant. Bus coupl ers can also
be used in parallel to increase the t ransmission perform ance. A
maximum of two bus couplers may be connected in series be-
tween two participants which ex change information.
Parallelbus couplers
If the coupling capacity of a bus coupler is not sufficient, t he
transmission perf ormance can be increased by approx. 100%
by using a second bus coupler. This parallel connection of bus
couplers leads to limitat ions in performance if one of t hem fails
(this is not a redundant connection).
Redundant bus couplers
If the coupling capacity of a bus coupl er is sufficient, a redun-
dantsystem can be produced using a second bus coupler. In
this case, the second bus coupler automatically takes ov er the
coupling function if the firs t 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 f or remote bus coupling (BK-FF)
depending on whether the remote buses are of singl e or
redundant design.
All these modules are fitted in a d ouble-height subrack. This is
completely wired and equipped with all necess ary plugs and
guiderails.
Mode of operation
A bus coupler acts like any ot her participant on the bus. It has
an address on every bus. A par ticipant on bus 1 sends a mes-
sage to a participant on bus 2 by f irst addressing the bus cou-
pler. This stores the message briefl y independent of the current
message transfer on bus 2 and acknowl edges receipt to the
transmittingparticipant.
The bus coupler transmits the m essage on bus 2 if it becomes
the master on this bus. The par ticipant 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 remoteb us 1
Redundant remoteb us 2
BK Bus coupler
UI Bus converter
Fig.4/19 Par allelbus coup lers, 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This catalog is out of date, see note on page 2