Festo CPX - Formula for Maximum Cable Length

A. Technical appendix
A−10
Festo P.BE−CPX−SYS−EN en 0902e
Formula for maximum cable length:
L v
NJǒ
U
Bmin
* U
OUTńVALmin
Ǔ
@ A @ Ë
CU
Nj
{
2 @ l
2
) l
1
}
Meaning
· Without pneumatics: V
OUT/V A Lmin w
18 V
With Midi/Maxi pneumatics: V
OUT/V A Lmin w
21.6 V
With CPA pneumatics: V
OUT/V A Lmin w
20.4 V
· V
Bmin
= minimum operating voltage supply (on the power
supply unit)
· Current I
1
= current for electronics and sensors
· Current I
2
= current for valves and outputs
· 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:
I1 = 1 A;
I2 = 5 A;
V
Bmin
= 24 V;
CPA pneumatics: V
OUT/V A Lmin
= 20.4 V;
κ
CU
= 56
m
mm
2
@

Result:
L ≤ 27.49 m for A = 1.5 mm
2
L ≤ 45.81 m for A = 2.5 mm
2