Hardware reference guide

Networking
35013379 11/2011 253
Bus Topology with Fiber Optic Repeater
This type of configuration is used when it is required to increase the length of the
fiber link and increase the distance between drops on the RIO network.
The following figure shows the bus topology:
NOTE: The distance between nodes on fiber is limited by the maximum allowable
power loss from end-to-end (3 km over 62.5 µm fiber). Power loss includes the fiber
optic cable attenuation, connector losses at the fiber optic receiver and transmitter
ports, and the system margin of 3 dB.
NOTE: At each end of the bus, looping back the unused optical ports with a short
fiber helps using the diagnostics. For more details on the diagnostics, refer to the
Modicon 140NRP95400 Fiber Optic Repeater Module User Guide.
CAUTION
EQUIPMENT FAILURE
The loss of a single fiber optic repeater in this configuration disables the rest of the
network. It is suggested that the Self-Healing Ring configuration be used to avoid
this problem.
Failure to follow these instructions can result in injury or equipment damage.