Festo IFB05-03, Manual

Page: 137 / 154

A. Technical appendix
A−11
Festo P.BE−VIFB5−03−EN en 0503e
Formula for cable length:
L
v
(V
Bmin
− 21.6V)
· A ·
κ
CU
2 I
2
+ I
1
This means:
21.6 V V
VALVE TERMINAL
= 24 V ± 10%, minimum:
w
21.6 V
V
Bmin
= minimum supply voltage
(at the power unit)
l
1
= current for electronics and inputs
I
2
= current for outputs/valves
A = cable cross−sectional area (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
Bmin
= 24 V
V
VALVE TERMINALmin
= 21.6 V
κ
Cu
= 56
m
mm
2
· ≅ Ω
Result of example:
L
v
18 m for A = 1.5 mm
2
L
v
30 m for A = 2.5 mm
2