Contemporary Control Systems PCI20U Adapters - Manual (Page 6)

TD030700-0I
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Active hubs provide overall better performance than passive hubs since
greater distances can be achieved along with a degree of isolation.
Connect
each NIM to a port on the hub using RG-62/u coaxial cable. This length of
cable cannot exceed 2000 feet nor can the length of cable between two
cascaded hubs exceed 2000 feet.
However, up to ten hubs can be cascaded
thereby providing an overall cable length of 22,000 feet. Unused ports on
active hubs need not be terminated.
PORT 1
PORT 2
PORT 3 PORT 3
Figure 3 — Point-to-point connections are required
between -CXS NIMs and hubs
-TB5
Twisted-Pair Bus
The -CXB transceiver can be modified to drive a balanced cable system with
the addition of some parts.
This configuration is called -TB5 and it supports
shielded or unshielded twisted-pair cable such as Category 5. Dual RJ-45
connectors replace the single BNC connector in order to support the popular
modular plug connectors.
Follow the connector pin assignments in Table 2
when using this connector or when mixing cable types. Wiring between NIMs
is accomplished in a daisy-chain fashion with point-to-point cables
connecting the various NIMs to create a bus segment.
The end NIMs will
have one vacant RJ-45 socket which is to hold the RJ-45 style 100-ohm
terminator required to terminate the end points of the bus segment.
Use
twisted-pair cable and observe polarity. Modular plugs must be installed on
this cable such that they do not invert the signals.
Most satin cable does not
twist the pairs nor maintain signal polarity. Do not use this cable. To test the
proper cable connections, hold both ends of the cable side by side with the
retaining clips facing the same direction.
The color of the wire in the right-most
position of each plug must be the same if there is no inversion of the cable. If
this is not the case, the cable is inverted. Up to eight -TB5 NIMs can be
connected to one segment which cannot exceed 400 feet in length.
The overall distance of a twisted-pair network can be expanded beyond 400
feet if hubs are used.
Use a hub port that supports the same -TB5 interface.