Festo FB13 - Page 180

Formula for calculating cable lengths:
L ≤
(
V
O
− V
TERMINAL min
) ⋅ A ⋅ κ
Cu
2 ⋅
I
2
+ I
1
This means:
• 21.6 V: V
TERMINAL
= 24 V ± 10%,
minimal:
V
TERMINALmin
≥ 21.6 V
• V
Omin
= Minimum operating voltage
supply (at power unit)
• Current I
1
= Current for electronic
components and inputs
• Current I
2
= Current for outputs/valves
• A = Cable cross section
(uniform e.g. 1.5 mm
2
)
• κ = Conductance value of cables
(uniform e.g.
κ
Cu
= 56
m
mm
2
⋅ Ω
)
Example
I
1
=1 A;
I
2
= 5 A;
V
B
= 24 V;
V
TERMINALmin
= 21.6 V ;
κ
Cu
= 56
m
mm
2
⋅ Ω
;
Result
L ≤ 18 m for A = 1.5 mm
2
L ≤ 30 m for A = 2.5 mm
2
VIFB13 - 03/05 Appendix A
9701 NH A-11