Phoenix Contact PSR-CT Series, Руководство по эксплуатации, Страница: 34 / 69

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4.2 Fuse protection for the power supply
Protect the power supply externally.
Design the external fuse depending on the number of switches and the required power for
the outputs. Also observe the connecting cable used.
Observe the following rules:
Maximum current consumption of a single switch
Maximum current consumption of a switch chain
4.3 Requirements on connecting cables
I
max
= I
UB
+ I
FO1A+FO1B
I
UB
= Current consumption of the switch (see technical data)
I
FO1A+FO1B
= Switching current of safety outputs
(2 x maxiumum switching current, see technical data)

I
max
= n x I
UB
+ I
FO1A+FO1B
n = Number of connected switches
If you protect the safety switch and evaluation device with a common fuse, also observe
the requirements of the evaluation device when designing the fuse.
CAUTION: Damage to equipment or malfunction due to inappropriate connecting
cables
Observe the requirements on the connecting cables in the following table.
Table 4-1 Requirements on connecting cables
Parameter Value
Conductor cross-section, minimum 0.34 mm²
R, maximum 80

/km
C, maximum 120 nF/km
L, maximum 0.65 mH/km
Recommended cable type LIYY 8 x 0.34 mm²
Note that too high cable capacities at very low load currents may falsify the test pulses of
the safety outputs.
If you are planning a cable design that differs (cross section, material, etc.), please contact
Phoenix Contact: