Carlton Solid State Logic SL 9000 J Series, Руководство по установке

Страница: 33 / 58

Network (continued)
The network uses two different types of connection. ‘Drop’ connections between the
various rack-mounted units use 10base2 (BNC) cables, T-Pieces, and Terminators.
‘Point-to-point’ connections between two units use 10baseT twisted-pair cables,
which may also carry other signals, such as power lines. The rules and limitations
which must be considered when installing BNC network cabling are outlined below;
those for 10baseT cabling are described on the next page.
10base2 (BNC) Network Connections
For reliable operation, the following rules must be observed (see diagrams opposite):
• The network must be terminated using 50
Ω
T-Pieces and Terminators, as described
on the previous page. Each network device, or ‘drop’, must connect directly to a T-
Piece: cabling between the T-Piece and the device is not permitted.
• The number of network devices (‘drops’) that may be connected to a single
network cable ‘run’ (i.e. between two network terminators) must not exceed 30.
• The length of the network cable from terminator to terminator must not exceed
185m.
• If it is necessary to exceed either of the above restrictions, a network repeater may
be substituted for one of the terminators and an additional cable ‘run’ connected to
the other side of the repeater. Additional network devices (and repeaters) may
now be connected to this cable run, or it may be used simply to extend the
network length (not more than two consecutive repeaters are permitted). The ‘free’
end of the final cable run must be fitted with a terminator. Note, however, that each
repeater counts as a ‘drop’, and so the number of ‘drops’ that may be connected
between a terminator and a repeater must not exceed 29. The total length of the
constituent cable runs in such a network must not exceed 555m.
• The minimum length of the network cable between ‘drops’ is 0.5m.
• If the distance from rack to console exceeds 15m, SSL can supply longer cable
lengths (subject to the above restrictions) at additional cost. This should be
specified at the time of ordering.
10base2 (BNC) Network Termination
• Each BNC network must be terminated at one end by a 50
Ω
Terminator (SSL Part
No. 32TKB5TC), and at the other end by a special 50
Ω
Earth Terminator (SSL Part
No. 32TKB5TK). For the processor BNC rack network (see Page 26), the Earth
Terminator should be fitted adjacent to the rack, and the earth lead connected to
the rack via one of the rear door screws. Most systems will only incorporate a
single BNC network (local to the processor rack). If it is also intended to connect
BNC network devices local to the console, the two extra terminators required
should be specified at the time of ordering.
25
4.9.98
System Setup