Siemens SIMATIC NET PROFIBUS manual Between two DTEs 10 m

Configuring Networks

Table 3-5 Examples Illustrating the Configuration Rules

No special conditions if the length of the LAN cable	LAN cable > 10 m
between two DTEs > 10 m
		> 10 m

	S7-400	S7-300
No special conditions if the length of the LAN ca-	Bus cable, e.g.		5 m
bles between two DTEs is greater than the sum of	V = 1.5 + 1.0 + 0.1 = 2.6
values of both DTEs.
	5 m > 2.6 m (sum of the values in
If a bus terminal or a bus connector has a PG inter-		meters)
face, a connected PG connecting cable must be	S7-400
taken into account when calculating the values.			V = 1.0
	5 m		V = 0.1
	V = 1.5
		S7-300
Take the values of a group into account if the sum	LAN cable e.g. 0.5 m group
of the values is greater than the LAN cable bet-	V = 1.5 + 1.5
ween the DTEs.
	0.5 m < 3 m	⇒	group formed
Elements can be close to each other providing the
	⇒ sum of the values ≤ 5
total value of a group does not exceed 5.
	S7-400	S7-400
	0.5 m
	V = 1.5		V = 1.5

PROFIBUS Networks SIMATIC NET	3-7
6GK1970-5CA20-0AA1 Release 2 05/2000