Festo CPX-FB13 Electronic Manual page 32

1. Installation
1.3 Connecting the field bus
1.3.1 Field bus cable
Bus length
1-18
Please note
With incorrect installation and high baud rates, data trans-
mission errors may occur as a result of signal reflexions
and attenuations.
Causes of the transmission errors may be:
– missing or incorrect terminating resistor
– incorrect screening connection
– branches
– transmission over long distances
– unsuitable cables.
Observe the cable specifications. Refer to the manual for
your controller for information on the type of cable to be
used.
Use a twisted screened 2-core cable for the field bus in
accordance with PROFIBUS specification (EN 50170, cable
type A):
Surge impedance:
Capacity:
Loop resistance:
Core diameter:
Core cross-sectional area: > 0.34 mm
If the Festo IP65 plug is used, cables with a diameter of 5...8
or 7...10 mm are permitted.
Exact specifications on the bus length can be found in section
1.3.2 and in the manuals for your control system.
135...165 Ohm (3...20 MHz)
< 30 nF/km
< 110 Ohm/km
> 0.64 mm
2
Festo P.BE-CPX-FB13-EN en 0112NH