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Siemens TX-I/O Engineering and installation guide CM110562en_13
Building Technologies Principles of electrical design 2019-05-15
10.5.2.3 Examples with 4 remote supplies
~0 A
~0 A
~0 A
< 1.2 A< 1.2 A
< 1.2 A< 1.2 A
< 1.2 A
< 1.2 A
< 1.2 A
< 1.2 A
< Lmax
< 1/2 Lmax
< 1/2 Lmax < 1/2 Lmax
< 1/2 Lmax
<1/4 Lmax <1/4 Lmax
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M
~0 A
~0 A
< 1.2 A< 1.2 A < 1.2 A< 1.2 A < 1.2 A< 1.2 A
< 1/2 Lmax < 1/2 Lmax < 1/2 Lmax
<1/4 Lmax <1/4 Lmax
10562z143a
~0 A
< 1.2 A< 1.2 A
< 1/2 Lmax
<1/4 Lmax
L1 + L2 + L3 < Lmax
L1
L3
L2
N
< 1/2 Lmax
• The sum of all island bus cable segments must not exceed Lmax (see 10.5.1).
• None of the sub-islands must draw current from another sub-island (at maximum
load of the connected I/O modules).
• Each sub-island is limited to 1.2 A (capacity of the supply / the bus interface module;
no multiple supplies are admitted, as the island already includes the maximum of 4
supplies).
• Both examples have the maximum number of 4 supplies and 12 I/O rows.
• Example N shows that the topology is free (line or star, but NOT ring).
Notes