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TC2200R/S Bus
User's Manual
Rev. 2.2
Figure 3. Single Master Located at the End of a Bus
Figure 4. Single Master Located in the Middle of a Bus
Figure 5. Dual Masters Located at Each End of a Bus
Application Topologies
The optic signal transmitted to the right (or East) side of the unit is designated as the “A” direction, while
the optic signal transmitted to the left (or West) side of the unit is designated as the “B” direction.
Therefore, the optic transmitter A (labeled “TxA”) is always connected to the next unit’s optic receiver A
(labeled “RxA”). The same applies to the left (or "B") direction. Because the TC2200/2201 can transmit
to and receive from two directions, it allows for three different topology arrangements, as illustrated below:
Note: The Dual Master (optional) topology enables fault tolerance (similar to a self-healing function) in
many applications. If a fiber link becomes degraded or broken in this topology, the Host controller can
detect that the RTU is not responding to its broadcast message. When the controller's software is
configured for this type of fault detection, it will then re-route the broadcast message to the secondary
Master (through a secondary port), thereby reaching the lost Slave unit and RTU(s).
