Siemens SIMATIC TI500 Manual do Utilizador descarregar pdf (Página 21)

Network Installation

2-5

TIWAY I Gateway User Manual

The

TIW

Y I network cable consists of a main cable or spine with droplines

or taps for each secondary

. The maximum main line cable length, cable type,

tap length, tap spacing, number of secondaries, and maximum baud rates

are interrelated network variables and have a direct influence upon

network performance.

Figure 2-2 shows the relationship of cable distance to the number of

secondaries for different baud rates for two types of twisted-pair cable. The

cable distance (in thousands of feet) is shown vertically; the maximum

number of units that may be attached is shown horizontally

10 50 100 250

Cable

Unit Loading (Number of Stations)

19.2

kbps

38.4 kbps

57.6 kbps

15.2 kbps

15.2 kbps or lower

Belden 9860

Belden 9271

Cable Distance (1000’s of feet)

205

I000000

Figure 2-2 Number

of Local Line Secondaries vs. Cable Distance

As shown in Figure 2-2, when you use Belden 9860 cable (or its equivalent),

up to 75 stations can be attached to a network operating at 38.4 kbps and

having a spine length of 20,000 feet. At 1

15.2 kbps, the maximum length of

a Local Line network having 248 stations is 10,000 feet.

TIWA

Y I Network

Characteristics

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