SICK Flexi Loop, Руководство по эксплуатации

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4 Design
The safe sensor cascade makes it possible to cover a large distance. On the other hand
a large number of switches, sensors, actuators and LEDs can be connected.
Due to the cable lengths and the power consumption, it is imperative you pay attention
to two things:
• The total current in the safe sensor cascade must not exceed 4 A at any point! 3)
• The voltage VDC must be present at each input on a Flexi Loop node in the range
from 16.8 … 30 V DC!
4.1 Total current
DANGER
The total current within a section of the safe sensor cascade must be limited to 4 A!
The safe sensor cascade permits a maximum total current of 4 A. Use a suitable protec‐
tion device or current limiters so that the input current does not exceed 4 A.
The magnitude of the total current is dependent on the following factors:
• number of nodes
• current consumption of the sensors and actuators connected
4.1.1 Permissible total current of a section
The permissible total current within a section is dependent upon the ambient tempera‐
ture (
see "Division into sections", page 30 ).
Ambient temperature Permissible total current
1)
40 °C 4.0 A
55 °C 3.19 A
Table 3: Permissible total current within a section
1) At UL/CSA applications only 3.2 A.
4.1.2 Permissible inrush current
Limit the inrush current flowing through the PWRI connection of the PWRI power supply
accessory to less than 40 A. Failure to do this may cause the short-circuit limiter associ‐
ated with the power supply accessory to trip.
Possible solutions:
•
Use a suitable current-limited power supply unit.
•
Increase the electrical resistance between the power supply unit and the first Flexi
Loop node downstream of the PWRI power supply accessory to 0.75
Ω (e.g., by
reducing the wire cross-section or increasing the length of the cable).
Tip: Minimum length of the cable between power supply unit and Flexi Loop node
= wire cross-section × 25 m/mm
2 (e.g., 8.5 m for 0.34 mm 2 ).
4.1.3 Other limits
It is possible to connect sensors with a maximum current consumption of 3.9 A to the
OSSD device connection on the FLN-OSSD1000105 Flexi Loop node.
A maximum current of 2 A is allowed to flow through the 8-pin M12 female connectors
on the Flexi Loop nodes (A VDC).
4)
3) At an ambient temperature of 40 °C.
DESIGN
4
8015836/YT10/2016-05-24 | SICK O P E R A T I N G I N S T R U C T I O N S | Flexi Loop 27
Subject to change without notice