Festo DLP-VSE Series, Manual

Page: 43 / 112

3. Installation
3-19
Festo P.BE-DLP-VSE-... en 0206a
The maximum permitted length of a branch line depends on
the cable type and on the baud rate.
Baud rate
(in kBaud) Field bus length
(max.) Maximum per-
mitted branch
line length
9.6 1200 m 500 m
19.2 1200 m 500 m
93.75 1200 m 100 m
187.5 1000 m 33.3 m
500 400 m 20 m
1500 200 m 6.6 m
3000-12000 100 m —
Fig. 3/23: Maximum permitted field bus and branch line
lengths for PROFIBUS-DP depending on the baud
rate
Recommendation:
Use a cable with a capacitance per unit length of < 30 nF/km
as specified below.
Otherwise the permitted cable length will have to be reduced.
Cable specification as per EN 50170 (cable type A):
Surge impedance
135-165 Ohm (3-20 MHz)
Capacitance per unit length < 30 nF/km
Loop impedance
< 110 Ohm/km
Core diameter > 0.64 mm
Core cross sectional area > 0.34 mm
2