ABB AC 800M, User Manual

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Section 3 Fieldbus Topologies Bus spur lines
3BDS009029R5001 B 83
Bus spur lines
PROFIBUS PA allows spur lines. The length of each spur line is determined by the
number of PROFIBUS PA bus elements and by the area of application. The table
below is specified for spur length using the MBP transmission technology with
31,25 kbit/s transmission rate:
Table 9. Recommended length of the spurs
Number of spur cables
Length of one spur cable
(intrinsically safe)
Length of one spur cable
(non intrinsically safe)
1 to 12 30 m 120 m
13 to 14 30 m 90 m
15 to 18 30 m 60 m
19 to 24 30 m 30 m
25 to 32 - -
Please note that the permissible total line length (the total of the main line and all
spur lines) must not be exceeded.