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2 redundant media transmission, The tiway i network ports – Siemens SIMATIC TIWAY 1 User Manual

Page 82

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THE TIWAY I NETWORK PORTS

UNILINK HOST ADAPTER

4-8

USER MANUAL

4.2

REDUNDANT MEDIA TRANSMISSION

Most TIWAY I conformant devices support a redundant media scheme which
provides active access to a device over one of two independent media channels.
Should access to a device fail on one channel, communications can be
automatically or manually switched to the alternate channel. This type of a
circuit is illustrated in Figure 4–5. Examples of the software commands are
given in Chapter 2.

UNILINK

Drop Cables

Up to 254
Secondaries

Secondary Bus
(alternate trunk)

Bus

(main trunk)

Figure 4–5

Redundant Media Circuit

NOTE

Redundant media is provided to improve a network’s
mission reliability. However, the adapter cannot use
the dual media ports to access two independent
networks.