Contemporary Control Systems AI-FR Redundant Fibre Hubs - Manual

AI-FR
Fixed Port Active Hubs for Redundant Fiber Ring Topology in
ARCNET
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Local Area Networks
INSTALLATION GUIDE
INTRODUCTION
Traditionally, ARCNET has been cabled as either a star or bus network, but
never as a ring. However, under certain conditions a ring topology is
possible. The ring has merit when the goal is to provide redundant cabling
so that continuity can be preserved in the event of cable failure. If one cable
becomes disabled for any reason, another is still available to pass messages.
It is for this purpose that the AI-FR has been developed and implemented to
achieve fiber optic redundancy in an otherwise un-redundant networking
technology.
The AI-FR utilizes the same robust hub timing electronics found in
Contemporary Controls’ MOD HUB series of modular active hubs. This
includes precision delay line timing, digitally controlled for dependable
operation and reduced bit jitter.
The AI-FR is an application specific active hub that provides integrity status
of the redundant fiber backbone. Redundant network topology — defined as
a fiber optic ring with a local drop — is ideally established with three-port
hubs, each incorporating the principle of fault monitoring.
A fiber backbone ring up to 2 km in size and employing up to four AI-FR
hubs is possible. By decreasing the total fiber ring size, additional AI-FR
hubs can be attached to the network allowing more devices to share the
redundant ring.
The AI-FR operates from either low voltage AC or DC power. For DC
operation, a voltage source in the range of 10 to 36 volts is required. For
AC operation, the source must be in the range of 8 to 24 volts. Redundant
power supplies can be attached for critical applications.
The hub is available in two versions. The AI-FR/CXB hub provides fiber
ring continuity with a coaxial bus local drop while the AI-FR/TB5
accommodates a drop established by twisted-pair bus.