Remote range, bus components, Bus components

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Design

Remote range, bus components

The following therefore applies:

In the case of electrically isolated local bus interface modules, the ground potential of the bus interface is decoupled from the ground potential of the subrack system. In addition, the 0-V level of the interface logic is matched to the potential of the cou- pling partner via the local bus cable. This prevents equalizing currents from flowing via the local bus cable in the event of volt- age differences > 0.2 V between the grounds of the coupling partners. These currents would interfere with the bus traffic.

In this manner, it is possible e. g. to extend a local bus island (0-V island) consisting of basic and extension cabinets by means of external, electrically isolated local bus participants (N-AS/N-AT). Any local bus interface modules can be linked together within this local bus island since they are powered from the same power distribution subrack. The following conditions apply: max. length 20 m, max. 9 participants, where each bus converter UI also counts as one participant.

It is not permissible to mix non-floating participants with differ- ent earthing concepts, e. g. SIMATIC S5 or SICOMP M with OS 265-3 systems or interface module N-V.24 in the same local bus island.

The interface modules for the local bus have a redundant local bus interface. They are each connected to one another by only one cable which contains the redundant local bus.

The cables are fitted at one end with a front plug for connection to the local bus interface modules, the other cable end is pre- pared for the connection and is soldered to the front plug of the cable of the next interface module. A single front plug is re- quired for the n-th local bus participant. This is not necessary for standard connections, e. g. to the bus converter UI for the remote bus, since prefabricated cables are available with looped-through wiring to up to 5 plugs.

The total length of the cables must not exceed 20 m.

Remote range

Transmission takes place via a coaxial cable up to distances of 4 km. The signals are self-timing bipolar square-wave pulses. The coupling to the remote bus is reaction-free.

Up to 100 bus participants can communicate with one another via the remote bus. The remote bus and local bus are connected together via inductive bus converters UI. The complete bus system therefore has the same information.

Two autonomous bus systems are connected together via a bus coupler so that only the information intended for the other bus is transferred. The bus coupler is counted in each of the two au- tonomous bus systems as one bus participant.

Bus components

Local bus interface modules

Interface		floating	floatingnon-
module for
20-m local bus	Required to connect the following systems and
Type	devices to the CS 275 bus system

N-AS	AS 215, AS 235 and AS 235 K	x
(-8AC)	automation system

N-AS	AS 235 H automation system	x
(-8AA)

N-BK	Bus coupler	x

N-AT	OS 520 operation and monitoring system,	x
	AT-compatible personal computers,
	SICOMP industrial PCs and
	PG 770 programmer

N16-M	OS 265-3 operation and monitoring systems		x
	SICOMP M minicomputers

N-V.24	SICOMP industrial PCs and non-Siemens com-		x
	puters via V.24 or 20-mA current loop interface

N-S5	SIMATIC S5-155U programmable controllers		x

Cable connectors for local bus

To connect the interface modules for 20-m local bus to one another and to the bus converter UI. A front plug is required for the last participant on the local bus.

Front plug for local bus

Metal front plug with 2 cable inlets and contact points. The contact points must be used to connect the plug with a low inductance to the subrack.

Connection distributor

The connection distributor has a vacant plug connection to the redundant 20-m local bus for the connection of configuring aids (SICOMP industrial PC with PROGRAF program package) and bus diagnostic aids. It must be connected to the local bus via a separate cable connector for this purpose.

Inductive bus converter (bus converter unit UI)

A bus converter is required to connect individual participants or a local bus with several participants to a remote bus. It per- forms continuous signal conversion between the local bus and the remote bus or vice versa without intermediate storage. The coupling is inductive and non-reactive.

Standard locations:

Basic cabinet of the AS 235 and AS 235 H automation system

Basic system of the AS 235 K automation system

OS 265-3 system cabinet Remote bus connection unit

Bus coupler subrack

Remote bus connection subrack FAZ-S5.

Siemens PLT 130 . 1994

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