Contemporary Control Systems AI-FR Redundant Fibre Hubs - Manual (Page 5)

TD675300-0ID
5
Connecting Cables
Each AI-FR hub provides fiber ring continuity with either a coaxial bus
(/CXB) or twisted-pair bus (/TB5) local drop.
Connecting the Fiber Optic Cable
Bayonet-locking-style ST connectors (mechanically similar to BNC coaxial
cable connectors) are provided for attaching fiber optic cable (typically
multimode) of 50/125, 62.5/125, or 100/140 in size.
Connecting Coaxial Cable Bus Networks (-CXB)
The AI-FR/CXB allows RG-62/u coaxial cabling to various nodes via BNC
“T” connectors at each device. Each end of a segment must be terminated
with 93 ohms of passive resistance using a BNC terminator (BNC-TER). If
the AI-FR occupies one end of the bus, it also must have the added
termination. Make sure that all devices are -CXB compliant.
Connecting Shielded Twisted-Pair Bus Networks (-TB5)
The AI-FR/TB5 has dual RJ-45 connectors for communication with various
nodes via shielded twisted-pair cable. Each end of a segment must be
terminated with 100 ohms of passive resistance using a TB5 terminator
(TB5-TER). If the AI-FR occupies one end of the bus, it also must have the
added termination.
Determining Maximum Ring Length for the AI-FR/TB5
11.9 µ s – (Number of Hubs
•
330 ns)
Formula: Max Ring Length =
5 ns
Table: Max Ring Length versus Hub Count
Number of Max Ring
Hubs Length
2 2248
3 2182
4 2116
5 2050
6 1984
7 1918
8 1852
9 1786
10 1720