User Manual

C. Technical appendix
C−17
Festo P.BE−SPC200−EN en 0901d
Formula for maximum cable length:
L v
NJǒ
V
Bmin
* V
OUTńVALmin
Ǔ
@ A @ Ë
CU
Nj
{
2 @ I
2
) I
1
}
Meaning
· V
OUT/V A Lmin w
22.8 V
· V
Bmin
= minimum operating voltage supply
(on the power unit)
· Current I
1
= current for electronics etc. (24 V)
· Current I
2
= current for outputs, field devices and
proportional directional control valves etc.
(24 L)
· A = cross−sectional area (uniform e.g. 1.5 mm
2
)
· κ = conductance value of the cables
(uniform e.g.
κ
CU
= 56
m
mm
2
@
)

Example:
SPC200−CPU4 with basic components and field devices for
2axes:
I1 = 1 A
I2 = 2.3 A
V
Bmin
=24 V
V
OUT/V A Lmin
= 22.8 V
κ
CU
= 56
m
mm
2
@

Result:
L ≤ 18 m for A = 1.5 mm
2
L ≤ 9 m for A = 0.75 mm
2