Fundamentals of PROFIBUS-PA
A-6
DP/PA Link and Y Link Bus Couplings
A5E00193841-011
Bus terminating element for PROFIBUS-PA
To ensure trouble-free operation, the end of a PROFIBUS-PA line must have a bus
terminating element.
Use an RC element in series connection for the bus terminating element
(R = 100 $ 2 %; C = 1 µF $ 20 %). For components, see Appendix D.
Spur line
The maximum permissible spur line lengths are listed in Table A-1. Note also the
maximum length of the aggregate line (see above).
Table A-1 Spur line length for the DP/PA coupler
Number of spur lines Maximum length of a spur line
DP/PA coupler DP/PA coupler Ex [i]
1 to 12 Max. 120 m Max. 30 m
13 to 14 Max. 90 m Max. 30 m
15 to 18 Max. 60 m Max. 30 m
19 to 24 Max. 30 m Max. 30 m