Siemens SIMATIC NET PROFIBUS User Manual
Page 117
Passive Components for RS-485 Networks
4-19
PROFIBUS Networks SIMATIC NET
6GK1970-5CA20-0AA1 Release 2 05/2000
Properties
The festoon cable has the following properties:
S
The outer sheath contains halogens (PVC)
S
Conditionally resistant to mineral oil and greases
S
Resistant to UV radiation
S
Small bending radii both during installation and operation
S
Due to the smaller Cu cross-section of the inner conductors, the d.c. loop
resistance and the HF attenuation are somewhat higher which means reduced
segment lengths.
S
The sheath material is flame-retardant complying with VDE 0472 T804
test type B.
Uses
The LAN cable for festoons is designed for at least 5 million bending cycles at the
specified bending radius and at a maximum acceleration of 4 m/s
2
.
Note
During installation and operation, all the mechanical restrictions involving the cable
such as bending radii, tensile load etc. must be adhered to.
Stopper
Clip
Runner
Lead runner
Example of installation:
Kink protection
Pulling cord
to provide strain relief for the cable
Figure 4-10
Installation of the PROFIBUS Festoon Cable (Schematic)
Segment Lengths
Due to the increased loop resistance, somewhat shorter segment lengths are
permitted at low transmission rates (see Table 3.1). At transmission rates
≥
500
Kbps, the trailing cable has the same values as the standard LAN cable.